I took an elementary electronics course once. We had to build and align an
AM transistor radio. We had an oscilloscope and an oscillator and got mine
aligned pretty well. The parts quality varied from person to person, so some
radios were a little anemic, others would really punch a hole in the silence
S. Mine did pretty well. But of course I do not have an oscilloscope or
oscillator now. I do the zero beat thing. I also have some stereo headphones
if I really am intent upon identification. My hearing was pretty bad by the
time I left vietnam, and has since gotten worse, so the headphones make a
big difference. So how do they make receivers with such fine and stable
frequency readout ?

"tom Holden" wrote in message
om...
"Maximus" wrote in message
link.net...
4,789,980 cycles per second. How do I align my dx 394 so it is in better
alignment ? My receiver can go down to 100 cps.

I developed a technique for aligning the 4 oscillators of the DX-394
using only a 25kHz (or lower) harmonic marker generator, a software
audio spectrum analyser that reads audio frequencies accurately and my
ears. It's described in the DX-394 special interest group at
http://groups.yahoo.com/group/RADIOSHACKDX394/. With a modification to
the 2nd local oscillator, I achieved an accuracy of +/-100Hz across
the entire tuning range of the DX-394. For AM reception, you don't
need this kind of accuracy but it's a great help with SSB.

Tom