Don,
Thank you for the reply. That is what I have heard from others too. But how
come my new SX110 (in 1961) and my current SX99 (same circuit) doesn't "block
out"? Mike KF6KXG

Mike posted:
Thank you for the reply. That is what I have heard from others too. But
how
come my new SX110 (in 1961) and my current SX99 (same circuit) doesn't "block
out"?
--------------
Very good question. Could it be that some version of the receiver used a dual
gang switch that disabled the AGC when the bfo was turned on? If I can find a
SX99 schematic I'll check for differences.

Don

Don and others following this string,
The dual gang switch idea would explain it. I have a W7FG copy of the SX99
manual for the Mark 1B and 1C and the AM / CW switch is single gang. I am not
sure what versions my SX99 is. I am going to spend some time this wknd and
compare the schematics and pts lists a little closer. Maybe I can find a
difference. I am also going to finish recapping it while I have it apart.
Has anyone else out there with a SX110 noticed this behavior? Mike KF6KXG

In article ,
(Dbowey) writes:

Very good question. Could it be that some version of the receiver used a dual
gang switch that disabled the AGC when the bfo was turned on? If I can find
an SX99 schematic I'll check for differences.

Almost every rx of that era required you to turn off the AGC when using the
BFO, except for some high-end jobs that picked off the AGC ahead of the BFO
injection.

The Halli engineers who designed the SX-99 would have been doing everyone a
favor by adding the extra switch gang to cut off the AGC when using BFO.

This auto-mode switching was carried to further extremems later on by all
makers. --Mike K.



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