Maxtrac/Radius flat TX audio injection point

[wa8pyr]

All;

I've got a couple of UHF Maxtrac/Radius radios which I am planning on using as UHF link transmitters in conjunction with VHF Radius receivers in a satellite receiver installation. The VHF radios both have 16-pin accessory connectors on the back, so I'm OK there, but....

Both of the UHF radios have the 5 pin connectors; I need to find a place to inject the flat audio from the receivers so as to bypass the preemphasis circuits in the UHF transmitter. Where might this point be?

Thanks,

Tom WA8PYR

[Will]

Tom, there is no provision for "flat" tx audio input on the five pin logic boards. On the later 16 pin boards, there is an added input to the IDC (mic amplifier & limmiter IC651A. This is a 4.7uf cap and a 56k resistor in series going to pin 2 on IC651A. You could change the capicitor, C652 (.0068) to 4.7uf on the input to the IC651A and get the same effect using the mic input pins..

[Monty]

Hi:

The altrnative without affecting the
Mic Audio on the Mic jack so you can keep the radio original is to do the following

Flat Audio in=>-----)]+---////--Pin 2 of IC651A

The value of the Capictor should be 4.7uf
The value of the Resistor should be 56K Ohm


Since there is only 3 componets, you can
assemble all the parts inside a Small piece
of Shrink Tubbing, and wire it in direct.

Also, it would not be
a bad idea to hang a 100K Resistor to ground
off the Flat Audio Input Line. The ( Plus )
side of the Cap should go towards Pin 2

Works Well for me, keeps the Radio Stock.

Monty

<font size=-1>[ This Message was edited by: [email protected] on 2001-10-17 20:23 ]</font>

<font size=-1>[ This Message was edited by: [email protected] on 2001-10-17 20:24 ]</font>

[wa8pyr]

Thanks for the info!!

Tom WA8PYR