View Single Post
  #5   Report Post  
Old May 8th 08, 01:44 PM posted to rec.radio.shortwave
dave dave is offline
external usenet poster
 
First recorded activity by RadioBanter: Jan 2008
Posts: 341
Default On the subject of retro...

Drakefan wrote:
JoanD'arcRoast wrote:

In article , dave
wrote:


D Peter Maus wrote:

Telamon wrote:

In article
,
D Peter Maus wrote:


I remember, after several months playing with my S-53A, tuning
through a ham band, hearing that duck quack that could only be SSB
without a BFO, and pulling up the toggle marked 'CW.' Slowly
tuning across the band--actually, I was looking for CW on the
lower end--I heard one of the ducks become intelligible for an
instant.

That got my attention.

I went back and tried to duplicate that moment by tuning very
slowly through any of duck quacking I could find. And I did
succeed, on the 80 meter band, in receiving SSB, with the CW BFO.
Working my way through the HF spectra, I succeeded in other bands
as well. I was about at 40 meters when my grandfather walked to
the door.

"Do you know what you've done, here?"

I didn't have a clue.

So, he explained it to me. But I was convinced that given the
CW offset of the BFO, that I would only be able to receive LSB.
USB would be outside the passband.

Um...not so much.

The BFO had been zero beat tuned with incoming carriers by
previous owners. Which meant I could pull both USB and LSB through
the relatively narrow IF (though wide by comparison to today's sets.)

It was one of the most exciting discoveries I'd made in my
limited radio experience back then.

The next time I was at my grandfather's house, he took me down
to his radio room and let me play with his big boy toys. The
Hammarlund (which I have now,) a pair of RME's, and an FM tuner by
Hallicrafters.

I've rarely had that much fun with radio. Especially
getting to swing that big-ass tri bander around in the back yard.

Things accelerated pretty quickly from there. And got out of
control right away.



Anyone have similar moments of discovery/revelation?

That's the way single side band detection works Peter.


I understand that. That's not my point. The switch was marked CW.
And it was fixed, and supposed to have been offset. So when the
incoming was centered in the passband, a 1khz tone was heard.
Putting one sideband always out of the passband. In this case, the
upper.

By having the BFO tuned to zero beat when the phantom carrier was
in the center of the passband, I could then receive both sidebands
as necessary.

Primitive. And it worked.

When my grandfather showed me what I'd actually done, and we did
the math, it was pretty clear.

And keep in mind this was in the very early days, for me. I'd just
stepped out of my first crystal sets into this Halli. So this was
exciting stuff.

So, my question....anyone else had similary exciting revelations
during the early days?



I could shave off a sideband pretty cleanly with my R-390A 2 kc
mechanical filter. Judicious use of the BFO PTO, the RF gain and the
KC tuning knob allowed very clean SSB reception.



Mom got a new kitchen radio (with FM -- woohoo) so I got the old
plastic (GE?) AM tabletop... I unsoldered and re-soldered wires (with a
wood-burning stylus) at random on the front end, and lo and behold!
Radio Havana and Radio Moscow and BBC! I was hooked! (I was ten years
old... and remember soldering while the radio was plugged into the AC
mains -- HA,HA!)
-j


My revelation came when I connected a homemade digital frequency display
to my Hallicrafters S-20R for the first time in 1977. It cost about $100
to build it back then. It opened up a whole new world of accurate
frequency readout. It was a real luxury in those days.

If you know how, you can tune any radio with a bandspread dial to within
5 kHz by using a calibrated spreadsheet.