[Hallicrafters] Auxiliary RF gain Control For SX-71

[Philip B Atchley]

Hi All, 
I'm preparing the station here to set up (again) the Ranger Transmitter
in a CW station, this time using (for now) my Hallicrafters SX-71
receiver.  As I want to be able to monitor my own transmitted signal I
was going to modify (with no holes drilled) the SX-71 so that there would
be a secondary RF gain control that comes into play while transmitting,
this to lower the receiver gain and prevent receiver overload.  Plans
call for shorting out the AAuxiliaryRF gain control via the TR changeover
relay while receiving.

My first thoughts were to open up one of the leads to the existing RF
gain control and route it to the 8 pin Octal socket on the back of the
receiver, OR put the auxauxiliaryntrol in the panel hole presently
occupied by the (unused) tone control, routing the connection through the
8 pin octal socket.

HOWEVER, examination of the schematic appears to indicate that this chore
is already done for me via the receive/standby switch wiring!  It appears
that if I connect the Aux RF gain control between Pin 4 (RF gain line)
and pin 1 (ground) and put the switch in standby it should accomplish the
same thing.  I have a 5K wirewound pot that I'll probably mount on the TR
Antenna changeover switch assembly for this task.

Has anybody used that arrangement on the SX-71 to monitor their CW
sending?  Or failing that, could somebody check their SX-71 schematic and
see if I'm missing anything here before I do it?  I'd hate to find a
"gotcha" after the fact!       
       
73 from the "Beaconeers Lair", 
Phil, KO6BB   Merced, Central California.

All Real Radios "Glow In The Dark".
RECEIVER: Hallicrafters SX-71, Grundig YB-300

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