[TenTec] keying the Omni D with a modern PIC keyer

M.Wood mrwood at attglobal.net
Mon Nov 21 10:29:42 EST 2005


After using a Heath 1410 keyer for several years with my Omni D, I decided to 
try one of the newer PIC keyers.

The keyer, supplied by cwtouchkeyer.com, is based on the Jackson Harbor PK4. 
It uses a 2N7000 transistor for its switching output. Output as measured by a 
simple VOM is .001 volts; I am told there are about 2.5 ohms across the 
keying output.

When I plugged the keyer into the Omni D I got continuous key down --even with 
the keyer off! With some trepidation I decided to try reversing polarity 
--ground of keyer wired to center conductor of Omni D input key jack (and tip 
of keyer now to omni RCA ground).

Result: Rig now appears to key normally. I tried this for several minutes, 
with no apparent adverse effects. But not really understanding what was going 
on, I decided to go back to the Heath.

Question: Why does the normal configuration not work? And will reverse 
polarity configuration (eventually) do damage to the Omni D keying circuits?

Thanks,

Mike K2CSJ


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