Hello, new user here.
I purchased an AMT 3000 kit to broadcast my own content to the AM radios in the house. The assembly went near-perfect, wih only two resistor errors caused by aging eyes that were corrected before the unit was powered up.
It powered up, passed the smoke test, tuned it and the radio a few feet away was picking up the signal. I have it running with the shipped white wire antenna.
Gain, Modulation, and Compression are all working as expected. I do have the unit configured for the shipped antenna as instructed.
My questions are these:
1. I espected a range of ~100-200 feet. It seems to have a hard time going 20 (where the signal fades abruptly). Would grounding (lack of it) cause this? I've tied it into the ground (center screw) my AC junction box at the wall with no apparent effect.
2. When I do the tuning steps, I get about 7.4VDC with the DIP selecting 1000, and 5.4 at 1500. The manual did not particularly say what I should be seeing, but this is roughly what it peaks at.
3. Signal from the box is clean plugging in a battery-powered audio source. I get a small amount of what appears to be ground-loop noise with an AC powered audio source. I'm still experimenting with this.
Make sure to try the inductor above and below the one you used. Re-peak for each one and pick the one with the highest peak.
The voltages you are seeing are correct. Not only is that short piece of wire a lousy antenna, but the inductors used are not ideal either.
It has been some years, but when I attached an AMT 3000 to a base-loaded antenna that I made, I remember getting well over 10 V on the peak.
Joe
Thanks. I did try that and am running on the "one under" that gives about a 1V improvement over the suggested one.
I took it out of the case and double-checked too. Everything looks OK. I did try a different ground point and the signal did improve somewhat. At least it will go through a wall now.
Whether it's normal or not still needs to be determined. I'll have to tackle that when I determine the permanent location for the box.
Thanks.
I'll keep playing with the ground. The antenna is vertical but when it is grounded the fringe area (20ft) receivers get a slightly better signal yet the total range is still very poor < 30 ft or so.
If you put a wall between them the range drops even more.
I'm also using a mix of receivers - a 1939 Philco and a 2013 Onkyo. Both show poor reception with the AMT 3000, but receive local stations fine.