A correction to my earlier post describing the Jones filter as
implemented in the Scout/Argo, now that I home and able to
consult the radio's manual:
It is a 9-pole filter in total, and not 8 as I said. The fixed
portion is 5 crytals, and the variable portion is 4 crystals.
Also, according to the manual, the Scout/Argo filter includes a
notch at the BFO frequency to help with removal of the carrier
and opposite sideband. From the schematic, that appears to be
accomplished using one of the five crystals in the fixed
portion.
IMHO, it is that additional notch that makes the filter
effective for the Scout. And I suspect that is why the filter
might need to be matched to the microprocessor, to make sure
that notch and centering of the filter matches the specifics of
a radio.
Kevin, K9IUA
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Kevin Anderson, Dubuque IA USA, K9IUA
k9iua (at) yahoo (dot) com
http://postoilgeography.blogspot.com/
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