By positive do you mean it need a HIGHER voltage is key down?
If so it sounds like the keying circuit transistor has a wide range of gain
under the wrong "wrong" biasing conditions.
Peter
-----Original Message-----
From: Frank Grossman [SMTP:71042.1303@compuserve.com]
Sent: Wednesday, August 02, 2000 12:20 AM
To: Bob Naumann - N5NJ; CT-USER@contesting.com; Grossmanzz@aol.com
Subject: [ct-user] LPT Keying Cable? Problem
Hi Bob...
>>What is the solution ?
What was positive - what was negative ??<<
My Dad, Harry, W2LOZ <grossmanzz@aol.com>, actually gets the credit for the
heavy lifting in terms doing the wiring and measurements following the
suggestions I got from the list. The shack is in his apartment, and I'm not
there much of the time.
Anyway, here's how he explained it to me when he finally got the W1WEF keyer
to work: The IC-765, and probably many other radios, are wired for positive
keying. All the keyers and interfaces in the shack work fine this way, even
though some are actually hooked up to key negative, and theoretically
shouldn't work. Only W1WEF's transistor is fussy and must have the correct
polarity to work properly. A jury rigged cord worked, so, my Dad is wiring up
a reversing cord so for a permanent fix.
Hopefully, I've explained it better now...
73,
Frank
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