[AMRadio] Introduction


Bob Bruhns bbruhns at erols.com
Mon Jun 12 14:13:45 EDT 2006


Hi Conor!

Back in the 60s, I used to listen to medium wave DX on car radios and an old, old radio console from the 1930s.  On the old radio, I
leaked some IF from the plate to the grid by connecting a wire to the plate and snaking it around to the grid cap, then tying it off
inside the plastic sleeve of a clip lead clip, and insulating it from the clip itself.  I attached the clip to a screw that stuck
out of the IF transformer, and I would swing the assembly around so that it moved the insulated wire around near the grid cap of the
IF amp tube.  This variable coupling produced an adjustable Q-multiplier effect, and I could get sharper selectivity for digging out
the weak signals.  I also built a noise clipper and attached it to the detector, and that helped hold the static crashes down.

The old radio could tune longwave, but I never heard anything much down there but navigation beacons, except one time I heard a
strong carrier come on, and a record played, and then the carrier went off.  I assume it was an old, old wireless phonograph that
someone had in my neighborhood.  It sounded too good to be coming from a parasitic oscillation in a record player, although that is
a possibility.

The fun started when I tuned around shortwave, and started hearing amateur radio people running AM.  Hey, I could do that...

  Bacon, WA3WDR




More information about the AMRadio mailing list

This page last updated 21 Oct 2017.