[TenTec] Inrad Roofing filter board in Omni VI

[Chuck Guenther]

Ira Franklin, K4YMQ, wrote: 
"I have decided to use the ATTN 
button to turn on roofing filter. "

That looks like it would be a very easy modification since the Attn switch is already set up to provide 13.5 V to turn on a relay, and the roofing filter control circuit requires a "high" to turn on the transistor relay driver.  

Someone else suggested using the "Voice" button to enable the roofing filter.  I've searched the board schematics in the Omni VI manual, but  haven't located the Voice switch to see what that would involve.

73,
Chuck  NI0C