- Posts
The http://sstran.com web site has been revised and now includes the new AMT5000 high effiiency AM transmitter kit in addition to the AMT3000 kit.
Orders can now be placed for the AMT5000.
The http://sstran.com web site has been revised and now includes the new AMT5000 high effiiency AM transmitter kit in addition to the AMT3000 kit.
Orders can now be placed for the AMT5000.
Thanks to everyone for your patience.
Carl Blare
Total posts : 0Congratulations PhilB on achieving a milestone in the Part 15 low power adventure with the bringing to market of your well crafted AMT5000 transmitter.
My order was placed moments ago and I expect many orders to follow as members of this website discover this good news.
mighty1650
Total posts : 0Glad to see a picture of the AMT 5000!
Looks big and cool!When I get enough Cash I’ll have to get one.
Carl Blare
Total posts : 0To move this notice to the top, I am pretending to add a comment.
RFB
Total posts : 0The toy box is already over flowing here. 😉
RFB
kc8gpd
Total posts : 0i got mine sitting here on my desk. it arrived thursday at moms i went and got it today.
here is a link to pic’s of the sstran kit i received from phill…
https://www.facebook.com/media/set/?set=a.103542016422103.6631.100002989142408&l=ba53b1b50f&type=1
this is a public link on FB and does not require a FB account to view.
RFB
Total posts : 0Ahhh…now I see what the deal is!
Pre-wound torroid and pre-soldered SMD chip eh!
No wonder all the excitement! (LOL)
@philb….do you have one that does not have the torroid pre-wound and the SMD chip not already on the board? 😉
Good looking little box. Enjoy the assembling!
RFB
Carl Blare
Total posts : 0On this website it’s been learned that AM antennas cannot share the same antenna location, the way FM & TV antennas can.
What has been mentioned is that FM and other VHF antennas can share the same tower by being separated by 1/4 wavelength, which is a short distance.
But AM wavelengths require totally separate real estate locations because 1/4 wavelength is a lengthy distance.
These thoughts are going through review as I anticipate placing the new AMT5000 into service when it arrives in the soon future.
Already I have two AMT3000s separated by about 100′ transmitting at 1550 and 1680kHz. There is also a dipole stretched from one of those locations to the other operating at 13.560mHz, and that signal gets into my 184.3mHz wireless mic receiver, and my 101.9mHz STL is catching an image of the station at 102.5mHz, which can be heard in the background on the 1550kHz audio. It’s o.k. if this description can’t be followed, it makes the point that locating transmitters becomes more and more complex as new ones are added.
It will only get worse when two more installations go into the mix: 970kHz AM carrier current, and 153kHz long wave.
Got to stop expanding.
Oh, almost forgot the revived CB transceiver that’s going in.
mighty1650
Total posts : 0Actually Carl your wrong on that one.
Several AM sites in the US share towers with other AM stations. It’s a practice called Diplexing.
This is a very common practice in Hawaii where tower sites are hard to come by.
Carl Blare
Total posts : 0I knew that FM antennas have been diplexed, but it is new news…… I guess all news is new news……… except old news, um, but I digress.
It is recent news to hear that AM antennas have been diplexed. So, what’s in it for us? I mean, can Part 15ers diplex?
mighty1650
Total posts : 0Us Part 15ers certainly could Diplex.
I’m not sure how its done, but it can be done.
considering all our antennas are 10M we don’t have to worry about the tuning aspect as much (as the big boys do). I’d imagine we’d need a filter of some kind to prevent the RF of the other transmitter from getting into the other AM TX.Heres an article explaining Diplexing, and includes a Diagram of how its done
http://radiomagonline.com/transmission/radio_diplexing_am_transmitters/
RFB
Total posts : 0“It is recent news to hear that AM antennas have been diplexed. So, what’s in it for us? I mean, can Part 15ers diplex?”
Remember our discussion in answering your question about taking two or more CC stations into a single coupling point?
The answer is through a diplexer. This is a device very common in all kinds of multiple transmitter/receiver installations where a “community” antenna or tower is used for everything.
Very old technique and not anything one could say is “new news”.
A Part 15 station can do the same thing. Grab a copy of any ARRL handbook publication and look at how a repeater station’s receiver and transmitter is combined to use a single antenna and feed line. Those use a duplexer unit, which is basically the same thing as a diplexer.
Just change the numbers for the frequency/s your working with
and you can make a diplexer or a duplexer for a Part 15 station.RFB
Carl Blare
Total posts : 0Upon first seeing this forum informing that the SSTran AMT5000 is now online and ready to go, I post-poned lunch so I could put my order right away. It went through without a hitch, and I have been here watching the window for the UPS.
Today a very promising message came through telling me that my order is being processed. That is very good news and the excitement is accelerating to the point where I may need health care services to come over here and keep me calm.
What I have just said is, to be honest, actually true. Yet, to be even more honest, has been dramatized as a method of promoting the AMT5000 to those who haven’t placed an order.
The pursuit of happiness is tiring. Stop wasting time, order your AMT5000, and actually experience happiness in its full splendor.
This endorsement is voluntary and Carl Blare has not been invited to spend Christmas on PhilB’s yacht.
wdcx
Total posts : 0A Part 15 station can do the same thing. Grab a copy of any ARRL handbook publication and look at how a repeater station’s receiver and transmitter is combined to use a single antenna and feed line. Those use a duplexer unit, which is basically the same thing as a diplexer.
Just change the numbers for the frequency/s your working with
and you can make a diplexer or a duplexer for a Part 15 station.If you don’t mind a duplexer the size of Kentucky. 🙂
kc8gpd
Total posts : 0don’t bother unless it’s a carrier current station. under part 15.219b the diplexer losses would eat up every bit of that 100mW
RFB
Total posts : 0“If you don’t mind a duplexer the size of Kentucky. :-)”
I was hoping for one the size of Alaska. :p
RFB
kc8gpd
Total posts : 0in reality i believe they are on average about the size of 3 Harris DX50 transmitters side by side. but then look at the power levels and wavelengths involved and the isolation needed.
Carl Blare
Total posts : 0Yesterday I found that the AMT3000 put a strong grade A signal in a straight line from the transmitter location out to where I was driving in the car for about 388′.
Today I had the AMT5000 peaked, connected, and still running at 113mW, because I hadn’t yet seen your advice of reducing power to 110mW or less, which I will do now.
Took another drive toward the west and the AMT5000 held steady out to 602′, clearly a more efficient signal than I had before.
Drove up the street the other way, east, and at the point where past signals have tended to fade out, the AMT5000 was still there and made it about twice as far as any other transmitter has in my experience.
My antenna is not the best antenna, yet the results are amazing. I wonder what these transmitters would do with a truly well installed antenna?
I hope my little trial run is of some interest.
RFB
Total posts : 0“I hope my little trial run is of some interest.”
It most certainly does….at least to those seeking real world application results vs the bench/lab/controlled results.
Your tests, regardless of the antenna, proves my whole point from the beginning..that comparing and testing with what is used under normal conditions CAN be done…thus HAS been done and you found a different result from one unit to another while using an antenna normally used for regular purposes…broadcasting and not bench testing.
Your results have been entered into the database for “Caged Emitter Squared” category.
Those operating with similar setups will no doubt find your data incredibly valuable.
I am certain that your data would not have been obtained by limiting the comparison to a lab bench and a piece of wire.
RFB
Carl Blare
Total posts : 0Thank you RFB for following the experience, and I again say the all important fact that my “antenna” is only an aluminum window with a base-board vertical wire feeding from the floor-up to the frame on the inside, and a wire attached outside to the top of the frame and run up the wall to the roof for a total of about 10-feet. It was only meant to serve the yard and house, but now it smears several blocks, in total radius.
Imagine how these outcomes would flare exponentially with a well designed antenna!
The AMT5000 is, no doubt, on a par with any other Part 15 transmitter in the world.
FURTHERMORE, my 1680kHz AMT3000, which also has a window-frame antenna but in a higher and better frontal location, reached DOUBLE the 1550kHz transmitter toward the west, but was slumpy going east. If I put an AMT5000 in that spot watch out! It would go Olympic.
Crazy thing is the 1550 back-yard transmitter was meant to be the weak, safe transmitter for paranide moments (paronoid). Now it’s too good.
The Part 15 life has its serious executive conflictions.
What I may do on 1550 is run at 1 mW.
radio8z
Total posts : 0Carl, your results as reported are interesting and encouraging but I am curious why you used 113 mW input.
Neil
Carl Blare
Total posts : 0Hello Neil Radio 8Z.
You caught me out on the power setting. I took a hasty “close enough” attitude as I did the test. Not defending my choice, but I am being forth coming about what actually happened. I could have stretched things by doing what a good politician would do, and say, “It was 100mW right on.”
A perverse way of being scientific is to be honest about being sloppy.
To save the day, here’s what I’ll do. I will reconstruct the test with a verified 100mW from the AMT5000.
I’m not sure if there’s any reason to repeat the AMT3000 first half of the experiment, although that would demonstrate whether two tests are consistent with each other. All right. I’ll re-do the whole test.
P.S. I just delved deeper into my psyche, and realize that I was subliminally pushing the AMT5000 by showing that one held sway over power output. It’s an advertising slip.
radio8z
Total posts : 0Carl,
Don’t fret about the power being slightly high. You did the correct thing by disclosing this. If you repeat the test with the power reduced to around 100 mW you probably won’t observe any difference so don’t go out of your way to do this.
As an aside, I have been on the air with my “high efficiency” transmitter for several months now and have yet to do a serious range check. Too many distractions around here. About the only thing I can say is that it covers my block with a solid signal where my previous tx. would become a little scratchy yet the signal was listenable..
Neil
Carl Blare
Total posts : 0Dear Neil Radio8Z:
Because of your casual observation that your new signal is less scratchy than the old one, we could in all fairness conclude that THEREFORE the new transmitter is in fact more efficient. All things being equal. That is, assuming you are using the same antenna in the same location.
And thank you for understanding my screwy honesty.
radio8z
Total posts : 0I knew this transmitter was more efficient than my other one because I bench tested it before using it on the air so it was not a surprise to me that the perceived improvement in the signal was observed since it was predicted by the bench test. The efficiency of the transmitter was not determined by the listening test.
Neil
RFB
Total posts : 0“The efficiency of the transmitter was not determined by the listening test.”
Measuring efficiency of single digit differences at the power levels involved is incredibly difficult to obtain by the ear alone, especially between levels of 100mW vs 113mW. A .013 difference wont even make the hump on the spec-an change enough to see it either.
But if a range increase is noted, and the power levels are within a reasonable range of each other…such as the .013 difference of 100mW and 113mW, the “quieting” at the outer rim of known acceptable listening range can also be taken as viable evidence of increased performance when the antenna normally used is not altered an any way with the exception of minor peak tuning from one transmitter to the other.
If Carl’s test were conducted at an unreasonable power setting..say 120mW or above, then the external antenna test and comparison of unit 1 vs unit 2 would be invalid simply because unit 1 cannot go beyond its designed power level versus unit 2 with a power adjustment pot. But I think Carl’s test at 113mW is very reasonable and within range of the established limits to conduct a real world test.
At the power levels involved, every fragment of efficiency and power transfer ratio (matching/coupling) counts. Those with the proper test gear obviously have an advantage to perform accurate measurements..depending upon if the test equipment itself is calibrated correctly for the frequencies involved.
But for the majority, even though I have lab grade test gear good enough to satisfy the field agent of my measurement and compliance logs, I speak for those majority who do not have the luxury of depending on an expensive piece of test gear to tell them if their setup is achieving that single digit efficiency advantage. The next best method for those folks is to take their new transmitter and connect it up to their existing antennas used to get the signal to the audience…be it a window pane antenna, or an outdoor 3 meter rod over a set of ground radials, or even a piece of wire strung up off a tree or flag stick off the side of a wall.
The whole point..in my opinion..is to achieve that single digit performance increase through the antenna system normally used for regular operations. The bench testing gives a good starting reference point, but it does not provide nor prove that the increased efficiency noted on the bench will also show itself through the regular antenna system. The only way to find that out is to run it through said antenna system and measure it with the test gear, or use the alternative method….taking a radio and noting if the outer rim range has improved or not.
There are going to be operators out there who are going to test their new transmitter into their external antenna systems and use basic methods of determining improvement or not simply because that is all they have to work with. In such cases, those who have done the testing in this manner should not be discouraged because it is not accurate. Who cares about the single digit accuracy! I want the improved efficiency to count where it really counts…out there in the real world where the audience is.
It stands to reason that if one notes an improvement, even if that improvement comes from better quieting of the carrier at the outer range limit..well in my book that makes the testing effort worthwhile and credible for others to base their testing.
I do not discourage accuracy or encourage setting aside the use of actual lab testing procedures. However every engineer knows that no matter what the test gear is telling you on the bench, it does NOT tell you what the results will be running through the external antenna system until specific tests are conducted with said external antenna system.
When I design and prototype, I rely on the test gear and bench to be the starting point, the reference maker. After that, its time for the real world testing and application. I never consider the bench/lab tests as the end all be all when the other half of the testing….using the outdoor antenna system….is left out of the loop.
Part 73 transmitter manufacturers have real world outdoor facilities equipped with antenna systems to conduct extended tests of that transmitter on a real antenna in real world settings. They do not just rely on dumping power into a dummy load and call it a day. Only after performing field tests do they slap their label onto the unit and crate it up to ship out. It is part of the overall quality control and quite frankly..if they did not do such extensive real world testing and provide a print out of those tests upon delivery of the transmitter, I would look elsewhere to a manufacturer that does conduct real world testing.
This is why I began to suggest comparing one unit vs another here with the new 5K unit. It is claiming things that result from the most basic setup…a piece of wire hung off the ceiling tiles in a controlled environment. That does not validate any sort of claim to improved performance or efficiency when no test data using real world situations are provided. It is almost a “either it will or it wont” grey area and that makes folks a bit nervous.
The economics these days makes anyone cautious. Although a good deal and fair price, the cost of the unit cannot be justified or meet with my approval to cut a check when there is missing data regarding real world performance.
Despite Carl’s “window pane” antenna setup, the testing he has conducted is credible and can be a reference for those who operate under similar conditions. His results are from real world application. If my station was relying on a window pane for an antenna, I would be far more comfortable cutting that check knowing that another user with similar setups did in fact get better results.
Now all we need is someone who has a 3 meter antenna system to submit their findings. I suggest that those who do submit their findings also include as much description about their antenna system as possible so as to give others an idea about what to expect from their own setup, perhaps even get new ideas to improve their antenna system..such as Carl noting about certain things with his antenna..and he got a suggestion to tune out the excess capacitance, and now that same window pane antenna is performing better on both the 3K unit and the 5K unit!
What better proof does anyone need that real world performance testing is worthwhile?!
RFB
Carl Blare
Total posts : 0Actually, the 20 pF coupling capacitor in my comparison test between AMT3000 & 5000 was only used on the 5000, based on the reasoning that:
Previously the 3000 had loaded into the antenna and could be peak tuned, whereas the 5000 could only be loaded into the antenna with the 20 pF cap and then peak tuned.
What I will try is a test in which both transmitters load via the 20 pF capacitor and the AMT5000 is set at 100 mW. Of course the power output of the AMT3000 is not adjustable, and is 100 mW according the Specifications, page 35, AMT3000 Manual.
Carl Blare
Total posts : 0Getting ready to re-test the AMT5000 with input to final adjusted closer to the target setting (100 mW).
It is windy today, and this must be affecting the capacitances of surrounding materials, because the reading is floating around at occasional times, of course with the audio silent, whereas the current normally finds itself and stays constant.
The AMT5000 Manual features a wonderful Equivalence Table on page39 showing a vast set of current/voltage settings that result in 100mW, and this got things going very quickly, combined with the fact things were already set at 113 mW. At first try I got 95 mW, next 110 mW, then settled on 102 mW, which I thought reasonable given the unstable atmosphere with regard to capacitance, which of course causes a changing milliWatt condition.
Shortly I will do the drive and observe the range with this setup.
radio8z
Total posts : 0Carl,
Continue field testing and reporting. Your results will be important. As discussed earlier, you need not be “laboratory perfect” with this, just describe your test conditions and observations.
Carl commented: “Your transmitter, as you certainly know, is a curiosity to the brethren. But it is personal intellectual property of yours. But we do naturally wonder if the design will later be made available for observation. Does it have output power control? That will be the new “cincher” for future adopters.”
Yes, it does have a power control. I do intend to share the schematic and test data on this when I can do a decent write up on the project. I can’t promise when but it could be soon I hope. I hate to tease like this but this is on my to do list.
Neil
Carl Blare
Total posts : 0Neil,
Your transmitter, as you certainly know, is a curiosity to the brethren. But it is personal intellectual property of yours.
But we do naturally wonder if the design will later be made available for observation.
Does it have output power control? That will be the new “cincher” for future adopters.
RiversideRadio
Total posts : 0Mine has shipped! Now I can watch for the delivery man too!
Keith
Carl Blare
Total posts : 0Riverside Radio is neck and neck with KDX, they both have shipment notices from SSTran.com.
An all-night vigil is planned in case Priority Mail happens to come in the middle of the night.
mighty1650
Total posts : 0I’m anxiously awaiting a special delivery of a transmitter myself, although on the other end of the spectrum, where moving pictures are formed and beamed into our brains.
Eventually I plan on nabbing one of these AMT 5000’s as soon as I get bored with my other works and have enough cash.
kc8gpd
Total posts : 0heres pic’s of the kit. arrived last week
https://www.facebook.com/media/set/?set=a.103542016422103.6631.100002989142408&l=ba53b1b50f&type=1
RiversideRadio
Total posts : 0(can you tell I’m trying to keep this one at the top of the active list?)
USPS claims mine was 50 miles from here 90 minutes ago and is scheduled for delivery tomorrow. Unfortunately, I’ll be at work and will miss the delivery but I have something exciting to be thinking about all day!
This is all new to me. Last broadcast was in 1982 and definitely not of the Part 15 persuasion. Marriage and family calmed me down, but the bug bite never healed and I’m looking forward to jumping back into the game. This time, all I want to cover is a campground and Part 15 should do it well.
I’m happy to be a part of this excellent online community and thank all of you for the great info I’ve found here.
Keith
mighty1650
Total posts : 0Same thing here, I’ll get my other end of the spectrum Transmitter tomorrow too, good thing I get home right after the mail arrives!
Carl Blare
Total posts : 0Either, RiversideRadio, you worked for a licensed station back in 1982,
OR
You did it some other way.The story must be interesting, either way.
One thing is being commonly shared:
We all have AMT500 Mania!
Carl Blare
Total posts : 0On a fine fall day at noon, the mail van pulled out front and I wondered if this would be the big day. Trying to remain calm I passed the suspenseful moments by remembering to breath, while reminding myself not to exhibit rapidly blinking eyes with head bobbing in all directions.
Up the steps he came, pyth helmet and official post office blue, and the mail box clanked. Acting falsely casual while suppressing the desire to kick the door open and rush out, I saw it…. just the size of the mail box, not an inch smaller, nor too big to fit. How did PhilB know the exact size of my mail box?
Once inside, I admired the package and labeling. Everything was perfectly straight and symmetrically placed with even the sealing tape applied precisely without wrinkles or bubbles.
Popping the box, the first thing on top was the manual, an exact match for its companion AT3000 younger sibling. Beneath this was a fully packed box with items that fit like the real design went into making certain that everything would fit perfectly in the box.
Paging the manual revealed a schematic that looked surprisingly simple, but a set of instructions that looked more detailed than any kit I’d ever built.
A whole new chapter in low power life is begun, and I wonder who will be first to get their kit built and on the air?
Carl Blare
Total posts : 0Part 15 dot US is so quiet because everyone is busy building their new AMT5000 transmitter from SSTran.com
RiversideRadio
Total posts : 0I can’t get past the beauty of it to start construction. I’ve been around a while and built a lot of kits, especially Heathkits back in the 80s, and this is one top-notch kit. I decided to purchase this due to the online reviews and it looks as though it’s going to live up to its reputation in every way. The quality of everything from the case, board, and parts to the well-designed packaging are of extreme high quality.
It arrived packaged so well and tightly that damage from shipment shouldn’t be a problem. Upon opening, the manual was placed just below the packing slip and is the first thing I grabbed. It’s extremely well-documented and comprehensible. I then reached deeper and pulled out the parts bags. Everything is grouped and labeled well, just as I’ve read in other reviews. So far, I consider this kit to be as high quality of any I’ve ever constructed, if not better.
If you aren’t familiar with SSTRAN and are planning to build an AM transmitter, I highly recommend this kit – it’s going to be a blast to build and use.
Keith
KD4PIPS I’d never heard of SSTRAN until a couple of weeks ago and have not been paid for this endorsement…etc…etc…
RFB
Total posts : 0Isn’t it neat how easy and quickly human beings can be steered in the modern age?!!
Careful now….too much excitement tends to lead to overlooked steps or outbursts of excitement causing sudden movement of limbs that might knock the table over or cause faulty solder connections.
Steady……steady now……easy……that’s it. Patience young padawans…all good things come in good time.
Once the honeymoon is over, it would be nice to read up on actual field tests and measurements to see if all the hub bub is warranted….that is what will make or break the decision here if one is to be added to the “X” box.
I look forward to the followups.
Happy assembling!
RFB
Carl Blare
Total posts : 0We should listen to RFB and not be too hasty trying to slap this kit together.
In fact PhilB speaks in the manual of the importance of being organized and arranging a neat work space.
On the other hand I don’t have time for all that. The circuit cards for the Big Talker shortwave transmitter are strung all over the work table and they are on the air, not yet in their cabinet. I could just build the AMT5000 right on top of all that and there wouldn’t be an electrical accident nor lost pieces. Until a minute later.
RFB
Total posts : 0I remember when I ordered a Panaxis AM-100 kit back in 84 and anxiously awaited its arrival. Like many awaiting their AMT 5000 kit, I too kept an eagle’s eye out for that delivery truck, checking every day, even sometimes sitting outside at the curb looking up and down the street!
Then it arrived, and like a kid in a candy store, rushed inside and began to open up the package. I was so excited my hands were shaking and I felt a rush of anxiety and wonder as I put all the parts onto the workbench. I used a cup cake baking pan to sort out all the parts into their own little section, making organization easier.
Fired up the trusty soldering pencil and it seemed to take a lot more time for that thing to heat up! Funny how that seems to work out that way!
After I started assembling the unit, about 10 percent into the project I had to stop and go take care of some other things. Securing the workbench by making sure the soldering iron was shut off, and power strip turned off, I left and was gone for only an hour.
Well to my surprise upon returning, my cat, which loved to use my workbench as a sleeping perch, decided to jump up onto the workbench and landed right on top of the cup cake baking pan which was still filled with sorted parts! Well..needless to say those parts ended up scattered, even a few flung across the room over thick shaggy carpet!!!
What was worse was that my sister who had the duty to vacuum the rooms of the house, had no idea what the cat did, and proceeded to vacuum the rug in the room!
After returning home, I found my cup cake baking pan missing, all those parts missing, and the cat happily snoozing on the workbench. My sister had taken the cup cake baking pan back into the kitchen, and no mention of vacuuming up small parts or anything, just the puzzling look of why I had a cup cake baking pan on my workbench.
In a haste, I ran for the trash can she used to dump the vacuum cleaner’s catch bag…only to find that the trash can was empty!! I proceeded at warp speed to the dumpster out in the alley…only to find it empty as well!!
I thought “well..there goes that project”.
Fortunately my sister had not taken the full trash bag all the way to the dumpster in the alley. She left it in the garage next to a few other large trash bags that were used to store extra blankets and sheets. It did not occur to me that one of those bags would contain the missing parts.
After sifting through the bag, I found the vacuum cleaner catch bag and started the process of recovering the missing parts….not exactly a clean thing to have to do, but necessary!
The things we will do for our hobby..even sift through smelly sticky icky vacuum catch bags!
I recovered every single missing component and completed the kit that evening.
Moral to the story….always expect the unexpected and never overlook the obvious.
RFB
MICRO1700
Total posts : 0WOW!
What a story RFB.
In the past I had used 2 different
AM-100s. Boy, did that transmitter
sound good!Bruce, Dog Radio Studio 2
Carl Blare
Total posts : 0The moral of the story told by RFB is….
If you have a sister or a cat, hide your small parts in a fire-proof bag up in the ceiling light.
kc8gpd
Total posts : 0I will be waiting quite a while to build my kit. one of them is i want the excitement to fade so i can take my time building it the other is i live in a 1200 sq/ft 3br apartment with my lady and her son. the lady don’t appreciate the studio sitting in the living room much less a work bench with test gear and projects sitting on it for extended period of time.
it may wind up waiting till i can get someone to build it for me or we move into a house where i will have a mancave er shop 🙂
RiversideRadio
Total posts : 0Getting ready to go on a 2-week trip, so there’s no rush here either. It has given me time to read through the manual a few times and get familiar with it (which is always a good idea). I’ve built much larger kits in less time than I plan to construct this one – going to take it nice and easy. Besides, the plan is to set this up at my retirement home in 2 years and anything I do now is experimentation.
But the delivery woman sure did take an eternity to get from the corner to my house.
Keith
Carl Blare
Total posts : 0This is very unusual. I also am taking a slow approach to actually building the AMT5000 kit. This is unique.
What we have here is a kit that is so appreciated in advance of the building stage, that we are content just to have it in the box.
Wow. What if we never build it? What if we just love having it?
RFB
Total posts : 0“What if we never build it? What if we just love having it?”
How about buying a 2nd unit and then there won’t be any worry about building it or just keeping it in the box.
The issue then would be…which one to build and which one to keep in the box! 😛
RFB
Carl Blare
Total posts : 0Ya but the question over “which one to build” could go on forever.
RFB
Total posts : 0Well if that happens, then maybe a 3rd purchase is warranted!
Having a spare around is always good anyway. Only this time the spare/s will be put to use every day with deciding which spare goes on what shelf or other, and decide if one stays in the un-opened box, or put into a display cabinet with everything arranged nicely like a fine dinner set….put a back light in the display cabinet…maybe a few varying color flashing LED’s…..maybe even some sound effects!
RFB
Carl Blare
Total posts : 0A perfect AMT5000 package will be placed in a trophy cabinet and backlit according to the words of RFBuddha.
A second AMT5000 package will be ripped open and built.
A third AMT5000 package will be held on a closet shelf as a spare backup.
Uh, uh, say. What happened to the AMT4000?
The mind. A terrible thing. To waste.
dietnews
Total posts : 0has anyone gotten around to doing performance comparisons between amt-5000, amt-3000, and the rangemaster? i am really curious what the difference is ‘in the field.’
also, does the amt-5000 need a baseloaded antenna like the 3000 or does that large toroid in the output tuning network negate the need for a solenoid inductor?
RiversideRadio
Total posts : 0The toroid negates the need, but I plan to build a low-loss base loading coil anyway because losses will be less. You can easily jumper the toroid for this. I can’t compare because I don’t own any of the others, but I’m sure this will do the job.
I decided to break ranks and begin construction, even though I’m getting ready to leave for 2 weeks and there’s no way I’ll complete it before I leave. I’ve installed all the resistors, diodes, and IC sockets. Hopefully someone else will have one completed by the time I return from my trip.
Keith
kc8gpd
Total posts : 0mine is almost built i have contacted phil RE: missing capacitor. the “R” in the fixed resister section should be “R2” didn’t notice any other manual errors also wound up with 4 extra resisters which i also let phil know about and the jumper blocks you have to break apart i wound up breaking the jumper blocks trying to separate them for the single jumper positions on the board.
other then that it went off w/o a hitch.
it’s sitting here on my console bridge in a static bag nearly finished.
just awaiting to hear from phil.
Carl Blare
Total posts : 0kc8gpd, much appreciation for your venturing with the first trial assembly, and have made note of R2 in the manual.
This coming weekend I expect to clear the needed work space and get started with a marathon build, and I will resist reporting every move here on the blog…
“Have just soldered C3, moving to C4, back in two minutes….”
RFB
Total posts : 0“Have just soldered C3, moving to C4, back in two minutes”
That was posted at 21:47 MT, it is 02:04 MT. A tad bit longer than 2 minutes eh?!! 😉
Well you know what they say about ending up with a bunch of spare parts……did not need them anyway!
Prediction: I predict that when all is said and done, and one of you have this thing all connected and operating, that you might see a slight improvement in range due to the increased efficiency of signal transfer from the TX final to the coupling stage at the output connector. Perhaps see a little less power supply current draw and cooler operating temps.
Cant wait to hear some field results!
RFB
RFB
Total posts : 0“This coming weekend I expect to clear the needed work space and get started with a marathon build, and I will resist reporting every move here on the blog.”
Perhaps you should make a special episode of LPH titled “The Great Weekend Assembly” and just narrate as you go along, maybe supplement with a few snapshots.
Or take it even further and set up the webcam or camcorder and shoot a video LPH episode.
Might be good program content for the LW Network too!
RFB
RiversideRadio
Total posts : 0I’m missing one capacitor and 2 transistors, but I do have 9 extra resistors. I guess it’s going to take a little while to work out the bugs – the disadvantage of being an early adopter I guess. I decided to install up until the point I have a missing part and then bag it up until I return from vacation. Now you have me paranoid about the jumper blocks – I should’ve attempted cutting them apart before contacting Phil about the other parts. I’ll be extra careful with those since I know to watch out for that.
I thought about taking a lot of pictures and posting them online but decided it was more important to get my hands on it than continue admiring it in the box. I’m glad to see someone else has taken on that task and I can’t wait to see the pictures.
Keith
Carl Blare
Total posts : 0RFB,
The idea of broadcasting the “making of the AMT5000” is such a good idea it must have been mine. I must have had that idea and probably made a note about it. The question is, how did you get it? Have you been reading my notes?I’m just acting silly. Thanks, RFB, great idea FROM YOU and I maybe, perhaps, possibly might do it.
But, video? I’m a radio personality (bit of a stretch), and you can’t see radio personalities. On the radio I sound like I LOOK LIKE Johnny Depp. But if I went on camera, things would be quite different, with me looking like….. can’t think of an ugly actor.
It could just show hands and electronic parts…. you’ve got me thinking about it.
kc8gpd
Total posts : 0i took hi res pic’s of each stage of the building process. i will get around to posting them to facebook soon.
RFB
Total posts : 0“I must have had that idea and probably made a note about it. The question is, how did you get it? Have you been reading my notes?”
Remote viewing has its advantages. 😉
I figured if not a contribution of a post during assembly, why not contribute an idea or two!
RFB
RiversideRadio
Total posts : 0Phil’s on the ball – already mailed my parts. I may have time to do some more soldering before vacation after all. I think this is the first time I’ve had something this much fun waiting for me when I get back from vacation…should help with the post-vacation blues.
I haven’t even gotten halfway through this and the excitement level is so high that I’m thinking about ordering an AMT3000 just for the fun of it (after the first of the year of course).
Remembered today that I have an old mil-spec grid-dip meter packed around here somewhere and a noise bridge (was a huge antenna experimenter way back then in what seems like a past life). Also have some huge air-core inductors, roller inductors, and assorted other fun things stashed in the attic. I think finding this site and SStran has caused the bug to bite again.
Keith
Carl Blare
Total posts : 0Based on the past few posts, I will do a Low Power Hour broadcast centered around the building of the AMT5000, but here is my golden rule: I will not report mistakes in the kit inventory. Those are strictly a matter already guaranteed by SSTran’s pledge to respond to any slips.
The entire nature of the proposed program will be a positive report on the Part 15 experience, a world in which everything goes right because everyone in that world is all right.
It’s a mantra.
kc8gpd
Total posts : 0phil is very on the ball. he does business like i do. that’s why i bought from him. very unusual in this day and age kudos to phil. he mailed my parts next day. yes i do believe the amt5k will be a big seller and once performance reports filter out about it, especially what it does compared to the procaster or rangemaster, i do believe it will be the one to give them serious competition at a 1/4 of the price.
Carl Blare
Total posts : 0This morning was spent in a calm, leisurely inventory of parts. Everything fine.
This evening as the sun went away I did 18 resistors, and will be on break until either continuing tonight or in the morning.
Looking ahead it seems like getting the output network set just right will be a fascinating new challenge, a definite difference from previous Part 15 transmitter experience. The quality and efficiency of the output to the antenna is definitely in the hands of the transmitter operator with the AMT5000.
An hour went by and I got all resistors installed and double-checked! Tomorrow the diodes.
Carl Blare
Total posts : 0As first light came in the window the diodes and IC sockets got mounted.
Next stop: capacitors!
kc8gpd
Total posts : 0here are pic’s of the sstran amt5000
public link
https://www.facebook.com/media/set/?set=a.111925762250395.16947.100002989142408&l=65d972012a&type=1
RFB
Total posts : 0“here are pic’s of the sstran amt5000”
I see a solder bead short! Just kidding! :p
Well it will be interesting to hear about the final results from all those assembling the kit. The most interesting will be the test resulting between the use of the internal toroidal
coil versus bypassing it and using an external loading coil.How much will the efficiency change between the two methods, and then comparing these results to the previous model’s performance or any other unit.
Good luck to all! 🙂
RFB
kc8gpd
Total posts : 0phil informed me last night that someone has already completed tested and is running their amt5000 using balanced input and external processing
Carl Blare
Total posts : 0The day started with Screw Terminal Blocks, continued into Power and Audio Jacks, and completed Small Inductors when break time arrived and time for a banana.
That’s happy news about the guy who is already testing his AMT5000.
The board layout is a grand work of art. Nobel Prize!
RFB
Total posts : 0“break time arrived and time for a banana”
Save them peels as those are useful in removing light scratches off CD’s and DVD’s.
RFB
Carl Blare
Total posts : 0The banana treatment for compact disks is useful information, RFB. I check out a lot of movies from the library, and the librarians will enjoy hearing that cure. I think the public plays pizza fingered frizbee with the DVDs.
Where are we in building the AMT5000? Just did Electrolytics, which sounds like a field of study from theology school, Quartz Crystal, Toroid Inductor, Variable Resistors, and stand poised to do LED Power Lamp and Insert ICs into DIP Sockets. Now only a page away from being fully done.
Had a tomato sandwich on sour dough bread with mayo. Does that make you hungry? That’s an example of “the power of suggestion.” We should be able to use that power to promote Part 15 broadcasting.
Carl Blare
Total posts : 0In went the LED Power Light, ICs into their sockets, and all preliminary jumper switches.
Plan to test on 1640kHz, a blank daytime spot not normally in use.
Set the frequency synthesizer for 1640 and the toroid inductor for that range.
Everything is probably ready to apply power, but another inspection of the circuit board and further manual study comes first.
Wait here, I’ll be back in a few minutes.
Carl Blare
Total posts : 0Later that same day, after reviewing the manual and gathering an understanding of what each jumper switch does, I powered up into a CB whip which is attached to the antenna terminal on the AMT5000 by a 1-foot clip lead. It’s less than 3-meters, more like 1.5-meters, but I reason that seeing it operate at less than optimum I will be able to more easily spot changes when output tuning is varied.
My first test frequency, 1640, was a bad idea because the AMT3000 operating at 1680kHz with cage monopole is ultra-strong, even 20-feet from its antenna. For one thing, my C.Crane Radio Plus hears traces of 1680 audio when tuned to 1640. When the AMT5000 was turned on at 1640 it caused a very loud image of 1680 to appear, albeit distorted.
Here is my theory about why I was getting so much interference from 1680: I suspect the toroid inductor is so resonant in its operating range it was causing the CB antenna to be very sensitive in the 1640 to 1680 range, so much so, that it was capturing plenty of energy from 1680.
Next I picked a frequency farther away, but still within the above 1350 region, per the manual’s instructions for high band operation. I picked 1400kHz, and now I have a clean quiet carrier on that spot.
The S-meter was at about half-mast, so I cranked the radio’s volume to hear buzzing behind the carrier, and tuned C1 until the noise decreased, then raised the power to the input of the final until there was no background behind the carrier and the radio’s S-meter was peaked.
The AMT5000 is declared ready for service at 2:55 PM this date, local time (CDT).
Party. My place. Bring portable radios.
RFB
Total posts : 0“The AMT5000 is declared ready for service at 2:55 PM this date, local time (CDT).”
That’s great! Have you tried it on the antenna system in place of the 3000?
RFB
Carl Blare
Total posts : 0Good job kx8gpd.
When will you be testing signal?
kc8gpd
Total posts : 0waiting on the missing parts to arrive. they should be up to moms by monday. i should be back home by tuesday and parts in by wednesday then i will test. my research shows in order to tune for true class E requires a scope which i do own. i have a lecroy 9403a digital 200 mhz quad scope. most will not get true full class e out of the circuit usinf a DMM. look up class e radio. there are two high profile sites with much research on the subject.
Carl Blare
Total posts : 0He was the first to pre-order and Rev. Chrysafis is the First to Complete his AMT5000 Kit!!!!
How can that be? He’s still waiting for parts.
Well, unless a secret kit builder has yet to appear to change the course of history, I am evidently the other kit builder currently in the game. But my whole religion is based on procrastination, and I love reasons to postpone things.
I have just completed all non-polarizing capacitors and next will be doing jumper headers. At this pace it will be several days before my AMT5000 is finished.
And before turning it on I’m spending a holiday weekend studying the output instructions, including the true “Class E Operation” referred to by Rev. Chrysafis.
By then I stand a chance of being the second to finish his kit. Maybe the third or forth. (Is it fourth or forth???)
Procrastination is the greatest nation in the world.
Carl Blare
Total posts : 0Jumper Headers installed. Taking another break before starting on transistors and voltage regulators.
Keep your project going. There is a lot of broadcasting to be done.
The world series does not include the world. But Part 15 radio does.
Later.
kc8gpd
Total posts : 0according to phil i was pre order and shipment number one 🙂
Carl Blare
Total posts : 0Yes kc8gpd, you are serial # 1. I mentioned that a few notes back, go see what I said.
According to my slow progress with building mine, you will probably also be # 1 with a finished unit, even considering the parts you are waiting for.
What kind of antenna will you have?
Carl Blare
Total posts : 0Stayed up late doing more work on the AMT5000, but now it is the end of night.
I did the Plasma Surge Arrester, Variable Capacitors, Resistor Network and Dip Switch.
But when I saw that Screw Terminal Blocks were next, I had that late night feeling that it was all over and time to close the window.
Meet me here tomorrow and we will go on!
Carl Blare
Total posts : 0My secondary frequency is 1550kHz, from an AMT3000 into three-elements forming a triangular cage monopole, two of those elements consisting of 6-foot high aluminum window frames in the wall.
As you recall, adding each element of a cage monopole lowers the total antenna impedance by 1/2 from that of a single 3-meter antenna.
That lower impedance, now with the new AMT5000 freshly installed at 1550kHz, does of course not match up with the recommended settings for top resonance, therefore some work lays ahead fiddling my way to the proper tuning. However, as it is now, the signal seems equal to what it was with the other transmitter.
Once true resonance is achieved, the big question will be whether a noticeable improvement in range can be detected.
Probably by tomorrow.
I will say this about this antenna installation which makes it interesting. The rear of the house faces into a hill which continues to travel upward for 150-feet and then there’s a McMansion up there like some kind of a giant sky bound tool shed. It is not a great spot for a transmitting antenna. But that’s exactly why I love it. Back there, if I can discover an improvement, it is definitely noticeable. For example, the signal faded out quickly with only a simple 3-meter antenna. But the cage-monopole filled in with solid signal out to the edges of what formerly was only weak signal. Yet, it didn’t extend the range, which is less than 200-feet.
EDITOR’S LATER ADDITION: It is important to mention the long ground wire that runs at ground level up the hill toward the back (south) because it alone has been successful in projecting our AM signal uphill. But the reason for mentioning it now is the added impedance load the ground side also introduces to the AMT5000 setup. The earlier trial test had no antenna ground attached.
Ermi Roos
Total posts : 0I will not get a new version of Windows unless it is at least in the SP1 state. Being an early adapter is not for me. Missing, or even excess, components are troubling to me. It indicates a QC problem. Back when kits were common, problems with component count were rare, although they occasionally happened.
I’ll be looking for posts and product reviews from the early adapters. At the asking price, which I think is a little less than a bargain, perfection is not too much to ask.
PhilB
Total posts : 0To Carl and others assembling the AMT5000:
I highly recommend that you spend some time familiarizing yourself with the tuning procedure on the bench with the 10 ft whit antenna wire attached before venturing forth with other antennas.
Connect the white antenna wire and stretch it out to full length avoiding proximity to conductive objects within a couple feet. Horizontal or vertical orientation is not important for this familiarization process.
Attach the black ground wire to anything grounded on your bench or connect it to the screw on an AC outlet.
Set your frequency to about 1500 kHz (midpoint of the toroid tuning range of 1350 – 1700 kHz). Carefully follow the instructions in section 8, RF Tuning. Be absolutely sure to use a voltmeter connected to the “RF INPUT CURRENT” or a field strength meter if you have one. Use the recommended tap point for the frequency and carefully watch the meter while rotating capacitor C1 through its range. Try the tap points below and above the suggested one to see the effect on the meter reading as you adjust C1. Make sure you find the PEAK setting. The peak should not be at either extreme of C1’s range. If it is, move the toroid tap to the next adjacent tap one way or the other until the peak is not at the extremes of C1. After peaking, ROTATE C1 ONE FULL TURN CLOCKWISE from the peak. This is important for maximizing efficiency Overall efficiency will increase by 10% to 20% above the efficiency at the peak meter reading point, depending on your operating frequency.
Once you are familiar with tuning and the meter readings, then you can venture forth to other antennas. Antenna capacitance is very important. The tap points suggested in the manual for various frequencies assume the antenna capacitance is in the 25 pF to 30 pF region. This will be true for a 102″ stainless steel whip, a half inch or three quarters inch copper pipe a few inches less tan 118 inches and the 118 inch white antenna wire. Other shorter, longer or fatter antennas will have lower or higher capacitance respectively, and should not be used until you are thoroughly familiar with the effect of the toroid taps.
Tuning by ear isn’t really possible if you want to get peak efficiency and performance.
RFB
Total posts : 0“ROTATE C1 ONE FULL TURN CLOCKWISE from the peak”
Wouldn’t that take it 360* away from the peak with that canister cap?
RFB
PhilB
Total posts : 0C1 is a multi-turn air piston capacitor with range of .6 pf to 6 pf. It covers the range in about 7 and a half full turns. One full turn is only about .7 pf.
The “RF INPUT CURRENT” vs. capacitance graph looks kind of like a horizontal S. As you increase the capacitance, the current will rise to a peak. Then, further C increase will cause the current to ramp down to a low trough and then rises up a little from there. The sweet spot is the midpoint in the downward ramp between the high current peak and the lowest current trough. This sweet spot is very closely approximated by turning C1 one turn clockwise from peak. Finding the peak tuning point is critical to good tuning. Then the efficiency goes up quickly as you advance down the ramp. Being off by plus or minus a quarter turn will only affect the efficiency by <1%, so the "one turn clockwise" step is a fast way to get good efficiency without tedious meter readings or dragging out a scope.
Phil
Carl Blare
Total posts : 0It was actually yesterday, in my entry titled “On Air,” that I proved that my freshly built AMT5000 worked the first time it was turned on, and I matched it to a CB whip that was close to the test setup suggested in the manual, and it tuned right up.
What I am unable to do is report on its range, because I (as yet) do not have a proper grounded yard antenna.
That leaves for another builder to report on range tests. I am not trying for greater range.
RFB asked what kind of results could be observed by substituting the AMT5000 for my AMT3000,s and those tests are invalidated because the “antennas” in both cases violate the cautions given by PhilB in the manual: Page 24, “For best range… the antenna should be positioned away from grounded metal objects…”
As I’ve previously described, my antennas are, by definition, grounded metal objects, namely aluminum window frames mounted in walls. It works, but must be very lossy, varying as to whether the outside is moist or rainy. These are not by any stretch the type of antennas for which these transmitters are designed. Any report involving such irregular antennas would be unfair and meaningless.
In any case, I have no doubt that the AMT5000 will do exactly what PhilB describes, given the intended antenna.
Carl Blare
Total posts : 0While slowly planning to build a real antenna, the AMT5000 is attached to the CB whip on the bench, and I ran two experiments:
-Using guesswork I set it up on the test frequency 1400kHz and walked 110-feet away, hearing the weakest of signals by the end of the path.
-Using PhilB’s instructions for peaking with a multi-meter I again walked out and the end of the path had a signal as strong as at the start! This only with an indoor whip! Range? Phil gives you range! But follow the steps.
kc8gpd
Total posts : 0side by side pictures of rangemaster and sstran. am10000 on right amt5000 on left.
https://www.facebook.com/media/set/?set=a.112617092181262.17340.100002989142408&l=0a994e11fb&type=1
Carl Blare
Total posts : 0Before shutting down the test I calculated the power input to final which is 286mW. Being indoors and only briefly testing this is no problem, but it is great to know that the AMT5000 permits setting the input to the final to the legal 100mW and I’m studying the method for setting the power.
Carl Blare
Total posts : 0Sifting PhilB’s lessons through my “stuck in my ways” brain, I realized how I’ve been missing the point about RF, and returned to the task of matching the AMT5000 into my home-brew window frame antenna, intended to be a compromise between an indoor and outdoor antenna.
Using the guidelines carefully described in the Manual and on entries here at part.15.us, the multi-meter inched the way to 378mW into the window array!
Before I correct for proper output power I’m going to tidy up and take a little drive because now I can see how different things are at 1550kHz compared to the AMT3000, which, really, was doing alright… just maybe shy a few feet in all directions.
I’ve already gotten double my money’s worth and am still thrilled over this new transmitter.
Carl Blare
Total posts : 0With the badly located 3-element cage monopole window-frame antenna the AMT3000 at full sun of day goes about 150-feet.
Now with the AMT5000 matched into the same antenna, but testing one hour after sundown with a Mexican station blasting in, the signal goes about 150-feet.
To make a fair comparison the test must be repeated in full sun tomorrow.
And remember, with this skimped and improvised atypical antenna nothing at all is really certain.
kc8gpd
Total posts : 0i sure hope i get more than that. i was expecting to at least cover the apartment building im in maybe the one across the lot too. i’m counting more on a carrier current effect then through the air
Carl Blare
Total posts : 0kc8gpd,
You’ll get a lot better than my ridiculous test with my window frame antenna. Everything is wrong with my antenna. In addition to being metal mounted in a wood and stucco wall, the whole surrounding wall contains stucco metallic mesh. It is against all common sense, but I went for cheap and quick.
By using a standard 3-meter antenna and good ground you’ll get better.
I posted my results hoping it would be obvious I was experimenting in silly land. No one should consider it a scientific test.
The transmitter is a real breakthrough for Part 15, better than what we had before.
PhilB
Total posts : 0Here is a link to a graph that shows how the RF INPUT CURRENT varies as capacitor C1 is tuned through coil/antenna resonance.
http://www.sstran.com/public/TuningPlotAt1550kHzWith28pfAntenna_1.gif
This graph shows the peak RF INPUT CURRENT ar the point where C1=2.4pF. The best Class E efficiency point is near the center where C1=2.9 pF. Overall efficiency is down 15-20% at the peak current point. In this plot the efficiency will be within 1% of maximum over a range of C1 settings from 2.7 pF to 3.4 pF.
The actual position of the S plot will be shifted left or right depending on the actual antenna capacitance and the Toroid tap selected.
You will be able to tune successfully if the peak current point is anywhere in the C1 adjustment range AND you can rotate C1 clockwise 1 full turn without hitting the bottom stop.
If your antenna capacitance is lower than 25 pF (shorter than the recommended antenna lengths), you will need to set the Toroid tap to a higher inductance value. If your antenna capacitance is higher than 30 pF (longer or fatter antenna), then you will need to set the Toroid tap to a lower inductance value.
Ermi Roos
Total posts : 0People who already have an AMT 3000 with the outdoor tapped loading coil and antenna installed, and have also purchased the AMT 5000, have the unique opporunity of comparing the AMT 5000 to the AMT 3000, as RFB already suggested. Whether the comparison can be done or not depends upon if the AMT 5000 is compatible with said AMT 3000 loading coil and antenna. Maybe SSTRAN can comment on the compatibility.
If the AMT 5000 is what it is advertised to be, it should have significantly greater range than the AMT 3000.
For me, this sort of comparison is crucial to my own decision to buy the AMT 5000, or not. If there is no significant range increase reported, I say “why bother?”
Carl Blare
Total posts : 0The AMT5000 Manual addresses some of your question, Ermi Roos. By jumpering S2 the onboard loading coil is bypassed and an external coil can be connected.
I do not yet have a proper antenna with loading coil and radials, so I can’t contribute a decent comparison, but someone will, I expect.
I want to praise one design feature that is extra handy…. the test probe sockets in the lower right of the circuit board make it super handy to make measurements.
Carl Blare
Total posts : 0Mention has been made, in the AMT5000 Manual, and in notes in this string, that the simple 118″ white antenna wire as supplied has a capacitance of 25 to 30pF, and that the coil windings are based on that general capacitance being present on the antenna.
I got to wondering about capacitance and hooked my capacitance meter probes between ground and each of several sample antennas. I started with the 118″ white wire antenna, and the meter orbited between 26pF and 214pF. By selecting “Min.” the meter locked on the minimum number (26pF), and selecting “Max” it locked on the higher number (214pF).
The lower number is exactly what the directions specify, but why the fluctuations up and down? Is that caused by RF energy being sensed from the air? (the antenna is not connected to a transmitter)
RFB
Total posts : 0“why the fluctuations up and down?”
The wire capacitance is being varied by inductive reaction to the surrounding environment. This could be nearby signals, close proximity objects, the orientation of the wire to ground.
Usually if your cap meter is set too high (sensitive), it will indicate these variables to the extreme. It is like turning up the gain of an amplifier, which a cap meter basically is an amplifier calibrated to indicate a reading corresponding to capacitance. Same is true with a meter measuring resistance or voltage. There are basic designs with less sensitivity and others that have a wide sensitivity. This is why some measurements call for a good DVM, those have an increased sensitivity compared to the basic types such as simple analog meters.
If your conducting measurements of this kind within the same room as the “window” antenna and its emitting RF energy, along with any other signals being generated, nearby lights and ballasts, that measurement will be influenced by these external sources acting upon that wire.
The effect can be observed when tuning a 3 meter antenna setup. As you move closer to the antenna, it is affected by inductive capacitance from your body, and the resonance will change a bit, and change again as you move away. That is why some of those all in one box transmitter units recommend a non-conductive, non-inductive tuning tool. Same is with aligning a sensitive receiver front end or transmitter intermediate stages with a non-conductive and non-inductive tuning tool.
Any wire, be it in a coil form or straight line, is subject to external influences and thus will react and measure accordingly.
Take a regular capacitor and connect it to your meter. Set to measure. Then take your fingers and “pinch”, or grab the capacitor with two fingers and note how the meter changes its reading, perhaps even change as you get closer to the capacitor. The more sensitive the meter is, the greater the influence rage will be and in turn would be affected at a greater distance from an external influence.
RFB
RFB
Total posts : 0“I do not yet have a proper antenna with loading coil and radials, so I can’t contribute a decent comparison”
Perhaps not an actual outdoor 3 meter setup, but you can perform a comparison with your existing antenna arrangement and make notes on any differences between the 3k and 5k units into that same antenna system.
Think of it as a unique system designed and constructed to KDX specifications. You never know…there may be other Part 15’ers out there working with similar situations.
RFB
RFB
Total posts : 0“the signal goes about 150-feet.”
Given the “window frame” antenna setup…150 feet is not bad.
I suggest taking the 10 foot long white wire and wrapping that around an extension cord of same length or a bit longer and then plug that extension cord into an outlet. Tune up and run that AMT5K as a CC system…see how well it performs that way.
Don’t forget to run the black ground wire to a decent ground like a cold water pipe.
RFB
Carl Blare
Total posts : 0Looking back to your (RFB) much appreciated comments on the nature of the art of capacitive measurement, can I safely assume that the lowest Farad reading of the otherwise varying numbers is most likely the true capacitance?
I made the measurements I wrote about after all my transmitters were turned off, but there are ballasts and so on plus maybe roving spirits in the room.
Yesterday I got so involved that I re-built my whole back-room window antenna, so any comparisons will have to start from the beginning, with the AMT3000 first, etc. And today we have rain, so not much will happen.
This entire adventure is great for Part 15 radio, and products like PhilB’s and of course this website and the wonderful members keep this hobby/profession alive and growing. As a promoter of personal radio stations I see one stubborn obstacle that discourages some people, namely the antenna.
People I’ve attempted to “convert” to Part 15 have balked at even having an inconspicuous white (or any color) wire discretely up the wall, and the other big attitude which keeps some people from adopting AM technology is a deep rooted preference for FM. I tend to align with promoting Part 15 AM, leaving the FMers on their own.
As I see it, there are three meaningful categories of Part 15 AM transmission antennas: the “Ultimate,” as described by PhilB and the true objective of the most serious operators, namely outdoor vertical with radials, but this requires locating equipment outside; the indoor antenna for the most simple approach; and my vision of an “indoor/outdoor” antenna, with my window-frame example serving as a way of accomplishing the goal of reaching the yard and inner-sanctum while keeping the transmitter inside, albeit not perfect.
This track is about the AMT5000 and only incidentally the antenna question, so I have opened a separate track titled “Indoor Antennas” with my aim of better formalizing whatever methods we can invent of integrating an indoor antenna with home decor.
Ermi Roos
Total posts : 0I wonder if the “one turn clockwise” business is still applicable when using an external loading coil and antenna.
Carl Blare
Total posts : 0I’m putting in my guess that the answer might be yes, that the same rule would apply to reach and then tune just past that peak-point.
RFB
Total posts : 0“that the same rule would apply to reach and then tune just past that peak-point.”
Is C1 still in the RF path to the antenna port when the internal toroid is bypassed?
I ask because it would seem that the circuit of C1 and the toroid is specific to their own purpose…using the internal matching network to a basic length of wire at the antenna port, and both C1 and the toroid are removed from the RF path when bypassing this internal matching network, passing on the matching task to the external loading coil/antenna system.
The TH transmitters have both internal matching circuits for the basic antenna wire setup, which has that fancy motorized ferrite bar coil system that automatically peaks the tuning for the wire, and in external “range extender” antenna mode, bypasses the entire internal matching system, passing on the task to the range extender outdoor antenna system.
RFB
Ermi Roos
Total posts : 0If C1 is not in the circut if an external loading coil and antenna are used, as RFB guesses, how would the tuning for high efficiency be accomplished? SSTRAN would know if C1 is in the circuit or not when an external loading coil and antenna are used and how the tuning is supposed to be done for high effieciency in that case.
kc8gpd
Total posts : 0looking at schematic it appears C1 never gets bypassed on c2 and the toroid can be.
kc8gpd
Total posts : 0should have missing parts today. think xyl picked up mail from mom this morning on her way home from job.
i will probably hook up the Aphex 320 D and SPF 300 for processing. drive it with my laptops using raduga automation, and the SSTRAN wire antenna. i will tune up the sstran to optimum and then do some testing then i will setup the hamilton in the same configuration and see who has the best range and sound.
keep in mind my hamilton belonged to bill blew of wsjl so it is a pretty old revision board and have no idea how it differs from later revision hamiltons.
consequently i believe he was the start of the issues with the ground lead and fcc. he got into a whizzing contest with langhorn field agents and dared them to shut him down. i’m sure fry’s rantings didn’t help since the FCC does read these forums. but if everyone remembers this is when the clustering and ground lead issues first came into play, quite a few years before the fry rantings. i lived in NJ at the time and had many conversations with him. i wonder whatever happened to him and his studio. me, bill, and mick got 3 of his 5 transmitters, but what happened to the rest of his equipment is a mystery. i recall radioboy was suppose to buy the remaining equipment from him but i think that fell through. that was the last it seems anyone has ever heard from bill b.
Update: i now have the missing parts
RFB
Total posts : 0So at that point…the external loading coil and antenna will have to be within a certain parameter in order to mesh up right with the circuit design to achieve that efficiency point.
Given all the variables from site to site, and one antenna/coil design versus another, that “window” to capture the efficiency point will be like a shot in the dark blindfolded with welder goggles on.
Well maybe not that bad!
But I suspect those using the external option will have to do some experimenting with their
antenna systems.It will be interesting to hear all of the results.
RFB
Carl Blare
Total posts : 0Verifying, the air trimmer C1 is on the AMT5000 antenna line at all times with a range of .6 – 6 pF. The filmtrim cap, C2, can be switched in with jumper S1, range 3 – 36 pF.
Looking at the instructions for CONSTRUCTING A BASE-LOADED ANTENNA, made available as an extension to the AMT3000, which is probably a standard form of loading coil/antenna, I don’t see that it would work any differently if added to the AMT5000. You find the tap on the coil with the best peak, then trim with the capacitor(s).
Finding the peak point to optimize the efficiency of Q1 (final RF output of AMT5000) is based on matching the capacitance presented by the loading coil/antenna. The instructions for constructing a base-loaded antenna do not mention that design’s capacitance, but it would seem to me that if it is out of range of C1 and C2 you would simply add a trimmer to your coil to reach the desired capacitance.
For comparison, the trimmer in the AMT3000, C5, is 12 – 100 pF.
If any of my view needs correcting please comment.
RFB
Total posts : 0There may be an instance where two or more locations will easily match up their existing antenna system to the 5K and be within the tolerance window to obtain the efficiency point.
But that is what it is all about…experimenting and finding what works.
RFB
RFB
Total posts : 0“Looking at the instructions for CONSTRUCTING A BASE-LOADED ANTENNA, made available as an extension to the AMT3000, which is probably a standard form of loading coil/antenna, I don’t see that it would work any differently if added to the AMT5000. You find the tap on the coil with the best peak, then trim with the capacitor(s).”
One can certainly have both the internal toroid coil active while feeding a second external coil down the line, but I think that would defeat the efficiency factor by a lot since two loading coils are in the path. One or the other, or perhaps both are going to rob signal or simply throw off the entire mess from even working at all.
Either way..it would seem that a bit of reconfiguring of the external antenna system is in order, be it adding a trimmer cap or more ground radials or reconstructing a new loading coil to mesh up the right way to the internal toroid of the 5K unit.
Who knows…that mail box antenna may come to fruition sooner than we think!
Hope to see more results and reports from owners of this unit and their existing systems.
RFB
Carl Blare
Total posts : 0Maybe I wrote something that gave an unintended notion, but I have not suggested using both the internal and an external coil at the same time with the AMT5k.
Please re-read my message with the knowledge that I am only addressing the addition of an external loading coil.
The jumper S2 bypasses the internal inductance coil.
kc8gpd
Total posts : 0i need those who have successfully got their amt5000 working to email me hi res detailed pictures of their board so i can compare to mine and see where i might have went wrong in assembly. i cant seem to get a solid static free signal even sitting right next to radio and i cant get even distorted audio on mine. i **THINK** i might barely have a carrier because i was tweaking with the tuning and heard something on my tuner but not full quieting nor any audio.
Carl Blare
Total posts : 0Can you make a high res picture of your board so that several of us could all inspect it? That, plus any high res pics you get of other boards might expand the chances of finding any mistakes.
kc8gpd
Total posts : 0i will in a little bit. probably after the xyl goes to work or if she goes to take a nap before work. if not definitely tomorrow.
Carl Blare
Total posts : 0I am still back here examining the performance of the AMT5k, but I am up against my insane window antenna, which has so much capacitance that it will not peak up. If I don’t get that “peaking” effect there is no point comparing to the AMT3000.
It appears that my window antenna has a capacitance around 4,310 pF. That’s way above the 26 – 30 pF typical range of a properly located 3-meter antenna.
I have noticed that stringing a 3-meter wire in the outer corner of this room gives a capacitance of 60 pF, which I assume is a “corner effect.” I’ll dabble some more with that. After all, PhilB did advise to keep the antenna away from surfaces and objects. I’m sure the reason is precisely because surfaces and objects drive the capacitance figure way up.
Someday I will build an outdoor stick with radials, but not this week.
Using an indoor 3-meter wire doesn’t get me a signal out in the yard, so I am mistaking windmills for giants (reference to novel “Don Quixote” – which may not make much sense, but that’s where my brain is).
But I am having fun and this is not a complaint nor disappointment.
The AMT5000 is a great gift to the Part 15 community.
This is real learning, here in the RF arena, and it is good for mental health.
RFB
Total posts : 0“It appears that my window antenna has a capacitance around 4,310 pF. That’s way above the 26 – 30 pF typical range of a properly located 3-meter antenna.”
You can attempt to tune out that excess capacitance on that window antenna by applying in parallel other capacitor values, bringing that 4k pf window antenna more into the ball park where you need it.
Just remember, capacitors in parallel result in opposite of parallel resistors. The capacitance increases, where as parallel resistors decreases in resistance.
And do not be afraid to experiment. Try some in both parallel and series. After all, its all about learning and discovering what works and what wont.
RFB
RFB
Total posts : 0“i might have went wrong in assembly. i cant seem to get a solid static free signal even sitting right next to radio”
Well looking at the images provided on your facebook link a few posts back, I don’t see any real problems with the exception of a few solder points that appear to be “cold” and “ringed” around the leads at a couple IC locations.
I would go back and touch up all the solder points and then confirm that the feed through connections points are making contact to their opposite sides.
Anyone remember those old RCA televisions that had those stupid rivets inserted through the PC board to make contact with foil patterns on the other side of the board, and the plague of bad connections from those feed through inserts?!!
Those sets sure made us mom and pop repair shops a good run of income for the day…that was about the only thing I admired about those particular sets..their steady income in soldering and inserting a small wire strand through those inserts to ensure a solid contact.
Check continuity on those feed through points. It is rare, but perhaps you have a board that has a flaky feed through somewhere…perhaps one or more. If there is one, I would check for more.
RFB
PhilB
Total posts : 0I agree wholeheartedly with careful examination of solder connections. I have seen occasions where they look good, but are still open. Mostly bad solder connections are caused by not applying heat long enough. I have always recommended flowing solder and then holding the iron on the pad for and additional few seconds (2 or 3 seconds). Sometimes, with insufficient heat, the solder will mound up around the wire lead, but not flow to the lead. The result is it looks good, but no contact. Holding the iron on the pad for an additional few seconds pretty much ensures the solder will flow to the pad and the lead. When in doubt, re-flow ALL solder connections for a few seconds with a clean tip and a touch of fresh solder . Doing this may take 15 or 20 minutes, but save hours of frustration and troubleshooting. Additionally, the methodical process of re-flowing every connection will force you to look at each one along the way, which may indicate some surprises you missed before.
I wouldn’t worry at all about continuity between the top and bottom in the plated-through holes. Stringent requirements of high hole count and high density, multi-layer boards have driven the PC manufacturing industry to a very high reliability level. Any manufacturer that didn’t do well in PC fabrication quality has long since gone away. SSTRAN transmitters use only a 2-layer board with hole and trace dimensions quite large by industry standards in order to ease manual assembly. We have been using the same high-quality vendor since 2003. I have yet to encounter a discontinuity in the plated-through holes, other than after a component removal that was done improperly. Checking for plated-through hold discontinuities would be tedious and error prone. I wouldn’t bother.
PhilB
Total posts : 0All the interest in connecting the external loading coil antenna to the AMT5000 came as a big surprise to me. One prime objective in the design was to eliminate the need for the external loading coil. The option is there, but it isn’t covered in detail in the manual. The web page: http://www.sstran.com/pages/sstran_buildant.html is so far unchanged and it only describes tuning for peak as is done for the AMT3000.
To use the external base loaded antenna with the AMT5000, the jumpers related to tuning should be set as follows:
S1 OFF
S2 ON
S12 ON
S13 ONJumper S2 bypasses the toroid. Jumpers S12 and S13 bypass the small inductors used for tuning below 1350 kHz. Jumper S1 should be open so the big trimmer capacitor C2 is not connected. C1 (6 pf) trimmer remains connected, but has no effect on tuning with the base loaded antenna.
The base loaded antenna capacitance is fine tuned by means of the length adjustment portion of the base loaded antenna.
To tune the base loaded antenna, adjust the tap point and the antenna length to get the highest peak as indicated by the voltage across the “RF INPUT CURRENT” test terminals. The equivalent to “adjusting C1 one full turn clockwise” is to lengthen the antenna slightly to add about .7 pf. Calculations show the required length increase adjustment is about 3 inches when using 1/2″ copper pipe.
RFB
Total posts : 0“All the interest in connecting the external loading coil antenna to the AMT5000 came as a big surprise to me. One prime objective in the design was to eliminate the need for the external loading coil.”
I certainly see the point in the design and it makes sense…but…
When someone takes the time to build a home made 3 meter antenna system, which could employ an elaborate ground system or unique loading coil..fine tune it and get it to perform at its peak, it should be expected that they will be interested in using that same antenna system with the new TX.
Let’s see what others report comparing the use of the internal vs the external. That is what I am really watching out for with all this.
RFB
PhilB
Total posts : 0Let’s see what others report comparing the use of the internal vs the external. That is what I am really watching out for with all this.
Me too, but I am confident the AMT5000, using just a vertical whip or copper pipe, without an external loading coil, will perform better than the AMT3000 with the external loading coil in the same location with the same grounding as the AMT3000 base-loaded antenna. It should perform at least as well, or better than the high priced competitor under the same location and grounding conditions.
Of course, using a big external air core loading coil should perform even better. That is an option I included for those who want to experiment with the ultimate Part 15 setup (this option isn’t available in the high-priced competitor’s transmitter). I think that is of lesser importance right now than validating the performance of the AMT5000 with just a vertical antenna and a decent ground system. Valid apples-to-apples comparisons against the high priced competitor transmitter are welcome.
RFB
Total posts : 0“Of course, using a big external air core loading coil should perform even better. That is an option I included for those who want to experiment with the ultimate Part 15 setup (this option isn’t available in the high-priced competitor’s transmitter).”
One thing is for sure the 5K unit has plenty of advantages over the other $$$ units, particularly the choice of the matching method.
Carl mentioned about one very useful feature, the test point holes on the board for meter probes. Nothing better than hands free meter probing preventing “slips and shorts”.
I mentioned the feed through points merely as another option to consider if all other checks don’t find the problem. But I think going over those solder connections will resolve kc8’s problem.
RFB
kc8gpd
Total posts : 0closeups of my sstran board
http://www.facebook.com/media/set/?set=a.263805160325243.59690.100000872822280&type=1&l=d7f2c94da5
Carl Blare
Total posts : 0Rev. Chrysafis:
Tomorrow when my brain is renewed I will set mine alonside the screen and compare everything visible to your pics.
You did a super neat job, so obviously you were very careful to get it right.
If nothing shows up in my inspection I’ll see if I can photograph mine for you.
Carl Blare
Total posts : 0This gathering of RF radio engineers provides the most wonderful scholarship on figuring out how to make things happen.
RFB, your idea of feeding my window with a small capacitance worked! Now I have reached my first peak tuning with the AMT5k!
At first I used a 62 pF cap, and that opened the door on C1 actually causing my current readings to change. With the direct 4,000 pF from the window antenna those readings wouldn’t budge from one number. But the 62 pF would not peak.
So I got a 20 pF cap and on S5, tuning for 1550kHz, I knew something was happening because the current numbers started going through more changes in the shortest turns of C1 than they had with any other jumper. It hit a highest number and started to descend and I knew this was the payoff of the week. There was even enough room to turn one full time clockwise to get that special notch.
I’m going to put this on my job resume’.
RFB
Total posts : 0That’s good to hear Carl! Now those who have window pane antennas have hope! 😀
RFB
Carl Blare
Total posts : 0Hello kc8gpd, Rev. Chrysafis:
I do spot something in your pics that would cause a problem.
S16 and S17 should BOTH be the same, jumpered or unjumpered, depending on your power.
If you are using AC power they are BOTH unjumpered.
If you have a DC power source they should BOTH be jumpered
kc8gpd
Total posts : 0i found that this am. removing them did not change anything. i have uploaded pics of solder side. same link as above.
Carl Blare
Total posts : 0To kc8pgd, Robert, in picture 8, in the upper left quarter of the picture, I see two leads that you might want to clip because they look like you might have overlooked clipping them, but they are not the problem you are looking for (I don’t think).
Have you tried, while it is turned on and being detected (you said there was some small sign of life) used a non-metalic (wooden stick, tooth pick) device to poke at each part and each connection? That is a method that has helped me find jiggly connections.
I will study the pictures some more once I get some other stuff taken care of. Keep thinking and looking, you will find it.
kc8gpd
Total posts : 0phil says i might have the resister network backwards which would keep the pll from locking on to a frequency. that is a big job removing and reorienting so i will wait a while till i feel up to that task
Carl Blare
Total posts : 0Encouraged by solving the “how to get a peak” situation, I will now conduct a comparison test between the AMT3000 and AMT5000. It will only be semi-scientific, but I will describe significant steps so that maybe we will be able to end up with a rough sketch.
To begin with, my antenna is “unapproved” in the real technical world, but it does the job I want it to do. The point here is that it is NOT an ideal antenna, and therefore the field of measurement will be in a smaller area than would be expected with a great antenna. There is no point describing the antenna in detail. The main thing about it is that it is less than perfectly efficient.
This morning I attached the AMT3000 and tuned it by setting my Zenith Transoceanic Radio for Manual RF Gain, turned the RF Gain down until I could just barely hear my signal at 1550kHz. At first the transmitter output tuning range was set for 82uH, an ordinary setting for this frequency. I tuned C5 until I heard the signal on the Zenith jump up to a louder level. But I noticed that C5 was fully inter-meshed, and changed the RF jumper range to 56uH, and was able to get an even louder RF level from the Zenith with C5 more in the middle of its range.
In a short time I will drive away, noting the distance not in feet, which would only be a wild guess, but in terms of “lots,” or “households.” I will be driving west, and in the past I have heard the signal at 1550 for a distance of 3-lots plus one cross-street.
But we are starting fresh with a newly modified antenna and a better-tuned AMT3000. The result could be different from before.
Ermi Roos
Total posts : 0While SSTRAN claims that using the external loading coil and antenna on its website is an option for the AMT 5000, it is leaving the related engineering work up to its customers.
Carl Blare
Total posts : 0At 1:30 PM CDT I turned on the car and tuned the radio to 1550 kHz. The signal from AMT3000 was received full strength right alongside the house. The transmitter/antenna was about 60′ away, facing south. I backed down to the street, north, then slowly drove west.
Despite the fact that the antenna is back behind the row of houses, it came in at grade A strength for 270′ on the street.
The compound angle that points back to the transmitter gives a straight line distance of 388′, figuring in the 152′ from the back of the house to the street.
The weakened signal at the boundaries lasted two more lots, approximately 180 additional feet.
The next step will be to install the AMT5000 and see how well it does by comparison. The weather is changing. It went from sunny to windy and cooler in two hours. If tomorrow at around 1 PM is somewhat like the weather today, I’ll do the second half of this signal contest.
kc8gpd
Total posts : 0Phil had me send mine back to him. he will De-solder and reorient the resister network and check everything out to make sure it’s functional and send it back to me.
I have no problems recommending anyone to purchase transmitters from phil. his customer service is top notch 🙂
Carl Blare
Total posts : 0That is so great, Robert, for PhilB to re-do the resister pack.
Once I read about what the mistake actually was I went back to your pictures and can just make out the printing on the resister pack which should face the other way, toward the DIP switch.
Thinking of how difficult your job would be, I myself got tired and took a break.
After all, yours is AMT5000 Number One!
RFB
Total posts : 0Indeed its fantastic the unit will be corrected and returned in working order. Those resistor packs could in my opinion have a better way of identifying their proper orientation…such as having the common lead separated from the others a little bit so that there is only one way they can be inserted into the holes on the PC board.
Imagine that!
RFB
Carl Blare
Total posts : 0Yesterday, in my previous note titled “Psuedo Science On The Air” I put the AMT3000 to a full-out tuned-up test at 1550kHz, complete with car.
At about the same time today, 1 PM CDT, the AMT5000 will be put through the same test!
Crowds are already arriving, bringing their own chairs, despite the cool air this morning.
Last night I had a surge of anticipation when I took a walk with the Grundig FR-200. The AMT5000 was turned on, peaked up, and running 113mW into the final. I walked the 152′ (measuring from where the antenna is) to the street. 1550kHz was coming in full scale, full blanking, if that’s the right term, no background behind the carrier.
Turned left, walked to the street corner, another 70-feet or so, and still no signal drop. Whoa!
Previously, after dark, 1550 tended to be quite lost in the noise down along the street. Things are really looking good.
kc8gpd
Total posts : 0i would drop that down to under 110mW i believe commercial stations are allowed 10% deviation from their assigned ERP.
Carl Blare
Total posts : 0Thank you Neil Radio8Z for your generosity to the cause of low power radio.
I am just headed out the door to do this next test with AMT5000.
And I am also looking forward to the modification to Big Talker to convert it into 1-Watt long wave.
There is never a rush on these things, it is always good to have things coming in the future.
Carl Blare
Total posts : 0Did the latest AMT5000 distance test in the present series, and while putting the data on paper I found a probable math error in the first AMT5K test which may actually have reached farther than reported.
I’ll make excuses later for my poor math, but tonight I will gather the data and corrections in what I expect will be an accurate report on the 2 AMT5K distance tests.
Carl Blare
Total posts : 0In studying the procedure I’m using to measure the transmitters I have spotted several ways of improving the strategy for more accurate results.
I have a Stanley Measuring Distance Tool with handle and wheels, so I can be very precise in feet.
It also occurred to me that the distances in my estimates were calculated along the sidewalk, but my car and radio are listening from out in the street, which is X-Number of feet farther away.
Yet, I WILL post today’s test and the corrections from the last AMT5000 test right here on this thread.
Then I will start from scratch with new improved testing methods and a whole new blog thread.
The first tests have been a test of the testing procedure.
Carl Blare
Total posts : 0This evening I poured over my test notes and find them confusing. That’s a bad thing in science. Tests must be replicable and the documentation must be clear.
I’m taking charge here, and here’s the plan…
Today’s re-testing of the AMT5000 will amount to this simple anecdote:
“With the input power turned down from 113 mW to 105 mW it didn’t seem to go as far. Instead of reaching the edge of the property of the 8th house west of here, it only made it to the middle of that 8th lot.” -end anecdote.
The newly announced plan is that I will check and double check every step of the way as never before. The next comparison test between the AMT3000 and the AMT5000 will be flawless.
And I know why I have been slightly scrambled…. it’s the solder smoke from building the kit! I went temporarily insane for a little while.
RFB
Total posts : 0Sounds like you are making good progress Carl.
RFB
radio8z
Total posts : 0Carl,
You are finding that the best way to learn science and engineering testing is to do it. In general, if you describe the test methods and conditions then the results are useful to others even if they choose not to replicate them.
One of my favorite questions to pose to my students when I taught laboratory methods in engineering colleges (three of them) was to write on their reports “Which voltmeter did you use?” The labs had up to 24 meters on the shelf so they couldn’t answer the question. Then I would tell them that if there was a question regarding their data they had no way to confirm that the instrumentation was calibrated properly. The lesson was to always record the serial number of any instruments used.
No, you don’t have to do this but it is one of the principles of good engineering practice and I only mention it to illustrate that these things are not as simple as they seem until one does it.
Anyway, I am enjoying with interest your reports.
I have a hiker’s GPS which gives the distance between two points which would be handy for these range measurements. Your distance wheel is good but it is probably hard to traverse a straight line. I have this funny picture in my mind of you driving across neighbors’ lawns with your door open and you holding the measuring wheel to the ground.
Neil
Carl Blare
Total posts : 0I may not have driven up on neighbor’s lawns but the auto portion of the trip did involve trash cans in the street, parked cars, rushing cars coming and going and me trying to count the houses on my left which corresponded with the wheel measurements taken earlier.
The Stanley measuring wheel was rolled along the side walk and at one time a man walking a giant dog was headed toward me so I veered a few feet down a paved driveway to give him room, therefore there’s a “driveway bubble” in my straight line.
And the straight line is a curve on the east/west direction, because these streets are all curvy. I think my south/north line down my driveway is straight.
Topography, which I think refers to the hills and valleys, is a missing factor in the measurements. I hold the secret belief this area was settled right on top of a field of indian burial mounds, it’s uphill in all directions from here, and the undulating upping and downing goes on for a few miles in all directions.
One of my many postmen said the reason we have so many different mail men is because no one wants this route because of all the ups and downs.
I’ll be sure to add the serial number of my meter!
RFB
Total posts : 0You could also just measure one of the sidewalk sections, which they will all be of the same size in the straight lane and merely count them then multiply. Add the distance from the TX point to the sidewalk to the total and there ya go.
Not exactly precise but I doubt that without precision techniques and precision equipment to do the testing, the results are not going to be precise down to the nano-fraction inch.
IMO..you already demonstrated the 5K does deliver where it counts with the improved efficiency into your real world antenna system. I think that any further attempts at precision here will only result in discovering the 20 ways to Doom when all it takes is 1.
RFB
kc8gpd
Total posts : 0got my sstran amt5k back will test within next few days. will order a fiberglass nema case too for outdoor mounting. have the vertical shaft pots and rca jacks installed for mounting in nema case.
Carl Blare
Total posts : 0Good news kc9gpd.
What is your antenna like?
kc8gpd
Total posts : 0it will be hooked to a 3m stranded copper wire with pvc jacket and grounded to cable tv line shield with an 18″ wire of the same and powered by a 3 prong grounded wall wart and fed by balanced audio. will be exactly what the rangemaster is hooked to now so i know tune up sstran to 1700 and set it 100mw and class e mode like instructions state.
i will have a good comparison between hamilton and sstran.
if the sstran performs better i may go to an air wound coil with a 1/2 inch dia 3 meter copper pipe.
nothing i do will increase range in my situation (will only see stronger signal fill in the weak areas if anything) i’m in apt and limited to indoor antennas and only temp outdoor antennas during night.
RiversideRadio
Total posts : 0I’m back from vacation and just finished construction of my amt5000. Took 3 enjoyable sessions and was a piece of cake to assemble. Ahhh… the smell of solder after all those years. Fired up the first time – have RF and audio, so the next step is a dummy load and scope to see what’s really coming out of it. I’ll post results once I find time to do that.
Also received email notification today that my weatherproof case shipped, so it’s all coming together. Looks as though I’ll be on the air much sooner than expected.
I think I’m going to like this hobby.
Carl Blare
Total posts : 0Excellent RiversideRadio, you know the right way to build a professional kit.
I am so proud (as another AMT5000 owner and a true believer in sstran products) that everyone who has purchased a newly released AMT5000 has very good things to say about it.
Keep it happening!
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