Phil 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 🙂
That 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!
Indeed 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
Yesterday, 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.
i would drop that down to under 110mW i believe commercial stations are allowed 10% deviation from their assigned ERP.
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.
If you don't mind a duplexer the size of Kentucky. 🙂
don't bother unless it's a carrier current station. under part 15.219b the diplexer losses would eat up every bit of that 100mW
"If you don't mind a duplexer the size of Kentucky. :-)"
I was hoping for one the size of Alaska. :p
RFB
in 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.
Yesterday 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.
"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
Thank 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.
Carl, your results as reported are interesting and encouraging but I am curious why you used 113 mW input.
Neil
Hello 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.
Carl,
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