Today, as many times before, I put on the seat belt for a ride to get chicken thighs for lunch, and as usual listened to the AMT5000 pumping out Free Talk Live with hosts Ian and Mark.
Today, as many times before, I put on the seat belt for a ride to get chicken thighs for lunch, and as usual listened to the AMT5000 pumping out Free Talk Live with hosts Ian and Mark.
As expected, the strongest part of the signal made it about halfway up the next block, keeping in mind that it is a very long block and I only have a Wintenna (windowframe antenna with added wire), and then the signal started going down into the noise. But, as is often the case at 11 in the morning, I could hear traces of the signal on the main street at the far end of the block, and those patchy traces come and go on the 3-mile drive.
In the parking lot at the store I kept the radio on for a minute because 1680 was unusually noise free and I could hear voices way in the background. I turned up the volume and was astounded that I was hearing Ian and Mark continuing to take phone calls!
Highly impressed by the performance of the AMT5000 I ordered double chicken thighs.
i haven’t played with it much
i haven’t played with it much but what little i did had impressive results. if i could ever get it installed in a weatherproof box over a large ground plane my guess is it will whoop the sh** out of the rangemaster at a 1/4 of the price
Ground Planes and Dreams
We share the ground plane dream, but I guess the difference is that I have the ground and have not been dictated to by a HOA, so I am free to build.
This is the drafting stage where everything gets mapped on paper. There needs to be signal lines from the basement to the spot, ground radials fit into the surrounding space… there are low bushes and small trees on the far side that are needed by the birds…..
Anyway, it is going to happen and yes, the exciting thing will be the tuning and peaking of the AMT5000 to see how far it goes.
Somebody else said they already have an outdoor setup. How is that going?
NEC Simulation
Carl, since you mentioned ground planes, I’ve read posts here where NEC simulations have been done. Has anyone done an NEC comparison of a full blown 1/4 wave radial ground plane (maybe 50 or 60 radials) to a much more conservative system with the same number of radials but only 10 or 20 feet long?
For someone with the time, space and money, they might go the expense if there were to be a significant improvement. It would be interesting to see what the software has to say.
Impressive report, thighs and all
Carl,
Your report on the range of the Amt5000 w/Wintenna is pretty impressive.
I had thought about using a window in my home for an antenna but was a bit concerned about the outer window being coupled to the aluminum siding on the mobile home. My mobile home is roughly 16 x 80 and the siding as far as i can tell is physically attached to the window frame.
Also i am making an un-educated guess that the siding is probably grounded somehow , although most mobile homes have the siding attached to wooden studs. The windows in my home are made of two parts, the outside storm window with a screen, then of course the inside window . They are not physically attached to each other.
So do you think my window would work as an antenna?? I would be using the vintage amt3000 lol.
You know those chicken thighs go great with some hot sauce poured on them and baked. MMMMM
Wintenna
Problem with the window pane antenna is that it is directional. So it is understandable that your going to see better than expected performance…in only two directions from that wintenna.
Your basically making the window pane into a loop antenna, nothing different from a wire wound loop on a square support structure, which those antennas are directional.
Which using a directional may be the way you need to go depending upon where your target audience is and your location.
Unfortunately for the “Wintenna”, being that it is your window frame, you cannot re-direct it unless you re-orient the entire house! I think in you case Carl, you got lucky.
Now…put that thing onto a 3 meter stick, which is OMNIDIRECTIONAL, and then lets compare apples to grapes.
It is safe and logical to say that for the directional pattern that your window frame is providing the results are favorable for that directional pattern. But it does not tell us how this thing works with an omnidirectional pattern setup, which is probably 90 percent of what is being used out there, the typical 3 meter stick, not window frames.
But for those who have no choice, at least this tells them it will work. Hopefully the window frame is pointing in the right direction!
RFB
A Good Thing
There is a good thing and that is that hooking the RF output of your transmitter to the screen and trying it will not harm the transmitter.
What I did was put the transmitter on the floor with a 2.5-foot wire vertical on the inside wall up to the window where it is screwed to the aluminum frame and on the outdoor side way at the top of the window there are four screws holding that part of the window together, and I removed and cleaned all four, and have four wires running up the outside wall to the underside of the porch roof, like a flat short cage- monopole section.
In one of my windows the frame is mounted in a wooden frame which is set into a brick wall.
If your frame is attached directly to the siding it probably would not allow much antenna action, but it won’t hurt to try.
The electric service to your trailer might be grounded to the framing, even with the wooden lifters.
Stick Anyone?
Is there anyone out here who jumped at throwing down the extra 150 bucks over the older unit that has this new unit hooked up to a 3 meter stick yet???
Although the reports to date with the “Wintenna” are good for that type of radiator, I am still not convinced about the new unit and the justification of the extra cost over the 3000. I certainly do not intend to buy one just to duplicate Carl’s Wintenna results. No need to. I want to read about units connected to 3 meter sticks. Maybe those results might convince me to pay the extra cost for a new unit that basically has only two new features over its older brother..an internal toroid and improved efficiency. To me those two things alone do not convince me its worth the extra 150 bucks.
So anyone out there going to connect this thing to a 3 meter system anytime soon?
RFB
As to the Stick
You know, RFB, it is kind of embarrassing that here in the gigantic country we live in, the home of Part 15 low power radio, here on the website devoted to low power Part 15, NO ONE HAS COME FORWARD WITH A STICK AND RADIALS TO PROPERLY TEST THE AMT5000!
What kind of a hobby is this where people talk about all these different ideas, but the most basic thing, stick with radials……hello!
On the other hand, as I get into another argument with myself, we do know that some of the people who do have radials and stick have not installed an AMT5000, we know that many members are prohibited from having a stick with radials because of official oppression, and there’s me, a well intentioned guy who is slow about building the stick.
So here we sit waiting for the right person at the right time with the stick and an AMT5000.
Patience.
Ultimate Part 15 AM Antenna
“What kind of a hobby is this where people talk about all these different ideas, but the most basic thing, stick with radials……hello!”
Nothing wrong with new ideas and experiments. But your absolutely right…what about the “Ultimate” setup and an AMT5K?
I find it rather unusual and somewhat interesting that we have yet to hear from someone with a 5K unit connected to an Ultimate Part 15 AM Antenna…and even more unusual…from the very same site/vendor along with the 3K, to which those who built that Ultimate Part 15 AM Antenna off that site along with attaching the 3K and now have a 5K..what are they waiting for…Christmas?!
Time is running out! HO HO HA HA!! :p
RFB
I’m waiting for christmas !
Hi,
I’m the one who posted those amt3000 range videos a while back. I plan to order the AMT5000 soon (next week) and install it on the same 3m stick being used for my AMT3k.
Once built and tuned, I should have a fair comparison with the AMT3k. The only thing I’m expecting is an improvement from the higher effeciency RF final. I don’t need the balanced audio or the improved coil.
I’ll have to check with SSTRAN on the outdoor enclosure option. If that’s not available yet, I’ll need to check local electrical supply stores.
Andre
That’s what I’m waiting for –
That’s what I’m waiting for – the AMT5000 in a weatherproof box, with a 3 meter whip at the top. Until that configuration is tested, then I’m from Missouri.
I’m likely going back to FM in any event. A good signal out 1 km (I’m in Canada) 24/7 is better than an OK one with noise out a mile or more but only 8 hours a day (winter sucks for AM!).
My Gut Feeling OUCH
Considering how well the AMT5K works
into indoor experimental antennas,
I really think it’s internal toroid
is probably as good as the AMT-3K with
the big antenna coil.
It’s just a feeling. I think Phil designed
the AMT5K to make the AM Part 15 journey
easier than it was before.
I can’t afford one right now. But I will get
one at some point. And if I am still living
in this house – it will go outside with the
3 meter stick.
Best Wishes,
Bruce, DOGRADIO STUDIO 2
Anticipation…It’s Making Me Wait….
I can certainly see the advantage to having internal matching saving both time and frustration to those not familiar with loading coil design. Kudos to Phil for bringing that concept a lot closer to all than the other two pricey options.
But a piece of experiment wire and a 1/2 inch OD copper pipe are two different puppies all together, and I agree the 5K unit will probably perform well beyond expectations. But probably is not a certainty until someone hooks a 5K unit up to something more than a dangling piece of wire hung from the ceiling.
Anticipation…..Anticipaiaition…It’s making me waiiaiiaiaiaiit. 🙂
RFB
also because of bulletin #63?
also because of bulletin #63? external air wound coils are still a grey area. having an internal toroid eliminates that risk especially with a non certified kit.
has anyone running one of carls air wound coils ever been cited?
conceivably the fcc if they
conceivably the fcc if they so desire could use that bulletin to shut down such a setup
Rumor Mill
“also because of bulletin #63? external air wound coils are still a grey area.”
Why is that exactly? Where in bulletin 63 is there specific rules regarding a loading coil on a 3 meter antenna?
Not to mention, where in the entire Part 15 section does it specify a loading coil cannot be used or would be considered part of the overall antenna length?
Lets keep in mind that FCC field agents are not the end of the line when it comes to legal interpretation. They have in the past been overturned due to their misinterpretation of the rules.
On the other side of the coin, a toroid coil isn’t any different from an air wound coil other than its orientation and configuration. Both still add wire length to the actual radiating element. And both serve one purpose..to make that short element radiate properly. The toroid could also be seen as adding length, does not matter that it is sitting inside the cabinet on the unit’s PC board.
So with all that in mind, and the lack of specifics regarding loading coils in the rules, I doubt anyone would have any trouble arguing the case using the FCC’s own rules as their defense..simply because no where in those rules are there any mention about loading coils.
If loading coils were a concern to the FCC, then those rules would at this very moment and ever since the inception of Part 15 rules, there would be specific wording relating to loading coils.
I think some have spread rumor and fear with this “grey” area because its easy to do just that when there is nothing specific within the rules saying either way. Simple fear mongering to what ends is anyone’s guess. Ego or the feeling of influencing others through lack of knowledge..on both parts.
I have yet to find any NOUO or NAL where a station got tagged because of using a loading coil.
Until either the rules change, or we start seeing a plethora of Part 15 AM stations using a loaded 3 meter antenna get tagged, all of this ASSUMING and grey area RUMOR pondering is not worth any worry.
Personally I think those who spread such rumors to induce fear into those wishing to explore this hobby are only doing so just to satisfy their own pathetic lonely lives because they simply have nothing better to do than to ruin everyone’s lives..and enjoyment of the hobby. Remind any of you of anyone who would do such a thing???
I can think of one right off..but no need to mention here as they no longer visit this board.
So message to all you agent wannabe’s…..go read the rules and become familiar with them first before trying to act like someone you are not.
RFB
Will Be Waiting
Andre_pro20g I will be waiting with great interest for your test with the AMT5000 and your incredible antenna.
My Lowes Store has nice outdoor electric enclosures, and I think they are easy to find.
Thanks for checking in with the good news.
We’re going to need a bigger box.
Not quite the quote from “Jaws”, but close 🙂
I may need to get a bigger box. I have big plans for next Spring. For no real reason, I want to do like the big boys but on a much smaller scale. The box will eventualy house a small FM receiver along with the AMT5k, if they get along that close to each other.
I’d like to make my transmitter fully wireless (I know there’s irony in there somewhere). My plan is to transmit audio via FM from my basement to the FM receiver in the transmitter box, then out through the AMT5k. I also want to add remote power by using a deep cycle battery and a small solar panel.
Like I said, no real reason, it’s just for fun. Isn’t that why most of us do this ?
My wife wouldn’t understand so i hope you guys do 🙂
Andre
Radiating element, what is it exactly ….
Just my $0.02 but I think the loading coil is part of the RF final circuit (the tuning stage) regardless of size. So if the length limit is applied to the radiating element (antenna), it should NOT include the coil just because it’s not attached to the PCB.
If someone says the limit starts at the point RF if produced, then it should start somewhere after the power transistor(s)in the final stage and should include the length of the copper traces on the PCB all the way through the tuning circuit, etc. But to me that sounds ridiculous.
Andre
BINGO!
“If someone says the limit starts at the point RF is produced, then it should start somewhere after the power transistor(s)in the final stage and should include the length of the copper traces on the PCB all the way through the tuning circuit, etc. But to me that sounds ridiculous.”
Badda bingo!
It would be ridiculous to the extreme. As well as be contradicting with units carrying a certification sporting a loading coil such as that of the Procaster and Rangemaster regardless of the type of loading mechanism in there..a toroid or air coil.
I think there is too much “reading into it” regarding this 3 meter limit. Going by the direct wording off the actual Part 15.209 rules, there is no wording specifying electrical length, which the use of the loading coil increases the electrical length of the short radiator, but does NOT increase its physical length. The wording points more to physical length.
But we all know the Part 15 rules are not clear in many aspects and are rather general…leaving it wide open to attack by either side of a debate. Perhaps intentional, who knows.
But until those rules are revised and clarified with specific wording relating to loading coils on a 3 meter radiating element, there is no viable ground (pun pun) for an FCC agent or even the FCC itself to stand on if tagging a station with a 3 meter antenna sporting a loading coil because their own rules do not specifically state the use of loading coils cannot be used and that loading coils adds to the physical length of the radiator..when in fact it does not. The loading coil only increases the electrical length, again no specifics within the rules stating we cannot extend the electrical length of the short radiator by use of a loading coil.
Its all there in black and white….or not there as I have just pointed out.
RFB
that’s what i say. i was
that’s what i say. i was simply bringing up a point that ***MAY*** be used by fcc to ding a kit built tx and home made antenna. i also went on to ask if anyone has been busted running such a setup.
oet bulletin #63
http://transition.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf
Bulletin # 63
I was not able to find where Bulletin # 63 relates to loading coils.
this would appear to be a
this would appear to be a good thing. i know for sure i seen it on the fcc website, but it appears to have disappeared.
now it seems to state direct all requests to… for rule interpretations.
Interpretation…It’s Confusing
“that’s what i say. i was simply bringing up a point that ***MAY*** be used by fcc to ding a kit built tx and home made antenna.”
Indeed. Please don’t misinterpret what I was saying in my post. I was not implying that anyone here was trying to “act” or “pretend” to be field agents. I was pointing out the plethora of that in a couple other forums.
In any case, even if the field agent were to tag a station for using a loading coil on a kit transmitter operating within the limitations of 15.209, that agent MUST provide the measurements taken when the case goes to court.
Now with that in mind, and the whole section of the Part 15 rules, a defendant can successfully argue their case that they did not violate any of the rules, and most likely have the case dismissed and the violation redacted simply because of the fact there is nothing specific anywhere in the rules about loading coils.
Then if necessary, one can go into the technical details of the obvious difference between “physical” length and “electrical” length and again reference to the rules and clearly show that there is no regulation regarding the use of a loading coil.
Even if the field agent insists, the fact is that their own rules and the definition of physical length versus electrical length cannot be argued..unless suddenly the laws of physics and the real world go right out the court room door and we interpret things through that black market dictionary with the blank lines next to each word.
If actual definitions of things were swept aside in such a case, then be very afraid of anything relating to law or description because we allowed it to be opened up to wild interpretation, which as we all know, can turn something that is into something that is clearly not and it wont matter.
At that point, we might as well declare due process as something ancient and no longer valid.
Guilty until proven innocent. Care for such a system like that? I do not.
Political correctness and semantics will destroy democracy, as well as the simple basics of ABC’s and 123’s.
RFB
where you been? they say
where you been? they say innocent till proven guilty but we all know that aint the case these days. even if proven innocent most these days will still think you guilty and that you just had enough to buy your way out of trouble including law enforcement.
Truth Is a Lie
In today’s backwards world we are all suspects even when proven innocent, so I agree with kc8gpd on this.
But so far you cannot be arrested for having a medium wave loading coil.
they just passed a bill
they just passed a bill allowing us citizens suspected of being enemy combatants or of giving aid to the enemy to be locked away in fema camps without due process. you can bet this will eventually be aimed at anyone who dares to speak against the establishment.
Two More Amazing Receptions
The AMT5000 continues to transmit with a rear window frame and some added length of wire acting as the antenna, with a one-wire buried ground aiming north and south. The initial long distance (DX) reception in a car parking lot 1.5 to 2-miles away started this thread, and that is south from here.
Yesterday I drove north and for the whole about 1-mile drive I could detect KDX 1680 riding in the background noise.
Now, today, I went southwest about 2.5 miles and was astounded to still hear KDX 1680 as part of the background noise. At two spots moving on the street the signal got louder very briefly.
I buy PhilB’s suggestion that this distance reception is most likely a matter of the power wires carrying the signal. Going with that theory, it would seem reasonable to expect a deliberate carrier current station in this area to be heard all over the place. That is actually frightening.
Also, if this is a power line phenomenon, is it not possible that some indoor radios are actually exposed to a fairly decent signal on their power wires coming from 1680?
build a blaw knox tower
build a blaw knox tower scaled down to 3 meters over a solid 30ft diameter ground plane and build a small doghouse to house a large low loss atu just like the big boys
Blaw Blaw Blaw
Just kidding about that, but “Blaw Knox?” You mean I have to learn something new again?
I know what a doghouse is, but Blaw Knox….????
What is it?
BIG NEVER MIND! I just “Searched Blaw Knox” and found the informative thread about the diamond shaped tower and found further proof that I have no memory. But I don’t remember not having a memory, so maybe I don’t… or do, as the case may be.
Part 15 World
“build a small doghouse to house a large low loss atu just like the big boys”
I coined it for the Part 15 world as “Puppy Hut” instead of “Dog House”.
Fits nicely don’t y’all think?!!
RFB
Be Sure to Latch
Be sure to latch the puppy hut, because a stray will move in.
To allow human access to the ATU inside the hut, you would need either to lift the hut out of the way, or have double-garage doors (miniaturized).
If the puppy hut had a basement you might be able to store stuff down there.
i just did some testing with
i just did some testing with the amt5000 at 1550 it went
1/4-1/2 mile from inside a first floor apartment of a reinforced concrete
and brick building clustered with other buildings of the same type. some
directions got 1/4 of solid signal. i have it grounded to the cable tv coax
shield in the apartment and hung the 3 meter wire from the wall and tuned it
per instructions. this is a good little transmitter. it also sounds good
with just an ipod and internal transmitter processing.
i was using a grundig g5 pocket radio to test range. i can’t imagine what it
would do with my asymmetrical audio processing, tuned for proper class e
operation, and back where i lived in NJ being we had a creek in our back
yard. bet i could have covered all of town there if it was over a good
ground plane buried near the creek with some good 8ft ground rods in the
ground to hit the water table. one bad ass transmitter (cost 230.00) and it
out does my 1000.00 rangemaster!!!!
AMT5000 test on a monopole with ground plane
I have tested the AMT5000 on a 3 meter vertical cage monopole 16 inches in diameter, made from 4x 14 AWG bare copper wires, connected by rings of 1/4 copper tubing at the top and bottom.
This is over a ground plane of about 12x 14 AWG bare and insulated THHN copper wires of varying length (limited in length in some directions as this is on a hill at the edge of the property). The shortest radial is 10 feet and the longest is about 40 feet.
The base loading coil is 16 AWG PVC insulated hookup wire wound on a 3 in. diameter polystyrene form (an old wire spool). The signal is passing through about 60 feet worth of wire in the coil. The internal toroid is totally disabled, it doesn’t even work with this antenna (impossible to tune; I am assuming my antenna has too much capacitance)
The AMT5000 is mounted in a weatherproof box right at the antenna base/loading coil and fed with power/balanced audio through Cat3 cable. The internal chokes L5 and L6 are disabled; I am considering the Cat5 run to be a radial. Testing showed that it didn’t really make a difference – assuming one more 24 AWG radial in an array of 12 14 AWG ones doesn’t matter.
The station was running on 1700 kHz. Intelligible range was between 3/4 and 1.5 miles on a factory car radio, depending upon the trees, buildings, hills, and such that were in the way. The station could be heard at 2 miles but was mostly unintelligible. Audio quality coming directly from the AMT5000 at close range is awesome, but bandwidth drops off severely with real-world obstructions in the signal path at a distance.
Reaction
After reading your posting, RankineCycle, several times I am inclined to agree with your finding that the lowered capacitance of your quite spacious cage-monopole does in fact explain why the transmitter does not respond to your antenna.
The design of the transmitter seems to be customized toward a classic one-element 3-meter antenna. That is a highly intelligent feature until the exceptional antenna variants enter the scene.
Perhaps coupling techniques will be found to allow for the mismatch and maintain the peak tuning in conjunction with the inbuilt toroid coil.
My solution to a mismatch was to place a 30pF capacitor in-line with the RF output, but I am suspect there is a better coupling method than that.
You didn’t mention whether your loading coil is peaked to resonance… what’s the story on that?
Tuning
The system is tuned to resonance using the procedure outlined in the manual, RF input power dialed back to about 100.5 mW.
I would guess that it is resonating with about 180 uH in the loading coil.