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Old September 12th 04, 12:37 AM
Jeffrey D Angus
 
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Steven Swift wrote:
I think you are right that the mechanical filter will be nice, but if it is
an SSB unit, won't the audio be messed up. I suppose that I should just leave
this part as-is until I get the rest working. Then if it sounds good, don't
touch it.


I think Peter's probably right, it's a 7KHz filter, probably just right
for "communications grade" AM radio operation. Which is you're going to
use this to listen to short wave broadcasting is a bit narrow. But good
for adjacent interferance.

Sideband sounds a bit "off" with these older receivers, as they use a
BFO with a large local signal mixed with the IF signal. Not too linear,
and the voice quality suffers a bit as a result. More "modern" SSB
receivers use a product detector (linear mixer) to add the BFO to the
IF signal.

Heh, then again, that was also a popular "modification" in the 50s and
60s as well. "Adding a product detector" to your AM/CW receiver for SSB
operation.

I always fight with myself regarding "authentic" versus better working.


The "big thing" in the 50s and 60s was to modify all the old war surpls
equipment to "make it work better than new." Some of the mods were good,
but were done by butchers. Others, no matter how meticulously they were
done, offered little or no improvement to the orginal operation.

Jeff


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