RE: IC-R8500

[Ron Parise <parise@xxxxxxxxxxxxxxxxxxxx>]

>Hi All,
>    I wonder if someone with an Icom 8500 receiver could
>look at their schematics and tell me if there is a way to
>install a switch that would deactivate the AGC circuit.  I
>would like to use the reciever for some radio astronomy
>experiments but the AGC is always ON in AM mode.
>    I have tried contacting Icom directly but they have not
>responded.  Their phone message says they are closed??
>
>Thanks,
>Chris / KF7KN

A couple of our club members here at NASA/GSFC have purchased 8500's.
I asked them last week if the agc could be turned off in order to use
the receiver as a piece of test equipment. I was told that not only can
you turn the agc off in software but you can program the time constant
to any value you want in increments of 0.5 sec. 

I don't think you need to hack the radio to turn off the agc.

Ron Parise, wa4sir