wes at johnston.net
Sat Sep 18 17:28:47 CDT 2004
I have a first run TNC-x hooked to a yaesu vx150 HT. I added a 1uF cap
in line with the audio since it didn't have one on that revision level
and that was what a kpc3 uses. Since it was an HT, I bridged the PTT
over to the audio with a 2.2k resistor. All is fine so far.... when the
tnc keys up the radio, it locks in transmit mode. Having seen this
problem before with tiny traks, I put a .1uF ceramic disc cap across the
PTT to ground inside the TNC-x housing. The housing is a cast aluminum
hammond box. Still, it locks in transmit. I hooked it to another
radio, a radio shack htx252 which also uses the same 2.2k ptt setup
(just like an HT). It too locks on TX.
The DB9 I'm using for a radio data plug is wired the same as a kpc3 (so
I can use the same cables), it is mounted to the metal box. The tnc is
grounded to the box by the three mounting screws in the corners of the
PCB. There are no wires exposed except for the radio cable and the USB
cable. It's actually a very neat (ie clean) setup.
Any other suggestions?
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