[Premium-Rx] RA6790 / RA6830 S meter tracking

[Carcia, Frank A. HS]

	Hi All,
	The S meter in both the 6790 and 6830 look the same as far as
hardware is concerned. I put the interface of
	the first IF pin diodes into Micro Cap so I could modify it for my
home brew second mixer. I found the interface 
	circuit can be fine tuned by changing the values of three resistors
to fix tracking errors in the S meter circuit.
	The resistors are the 2 - 1 Kohm resistors in series with the pin
diodes in the first IF and the 2.2 kohm
	feed back resistor of the op amp linear to log converter. I found
this converting to drive a pair of Mini Circuits
	PAS3 attenuators. There is a wide range of adjustments changing
these 3 values so it would be possible to
	change the S meter tracking. The s meter is an A/D conversion of the
AGC voltage compared to a table in software.
	
fc