> -----Original Message-----
> From: writelog-admin@contesting.com
> [mailto:writelog-admin@contesting.com]On Behalf Of Steve Woodruff
> Sent: Friday, November 08, 2002 8:57 PM
> To: writelog@contesting.com
> Subject: [WriteLog] ptt line resistance?
>
>
> I now have all mode ptt via cw line RTS.
> However... its not working. When i play
> SSB messages it is not triggering the
> rig's PTT line. I am connecting to the
> same port that my footswitch normally
> connects to... simple mono plug.
>
> When i hit a F-# button to play a message,
> i can see with a multimeter the resistance
> on my PTT line drop down to about 4-6 ohms.
> Not much.... but is that enough to keep the
> rig from triggering PTT?? If so, how can
> i drop the resistance?
Be sure the diode is not in the wrong direction. You did not give enough
information to really understand your circuit. Perhaps a text based drawing
would help. I use no diodes, just a 4.7 k or so to the base and the radio
directly connected to the collector with no resistance.
Be certain the Transistor is a PNP if Positive keying.
Be certain the correct polarity is used from the RTS.
If your resistance to ground with an Ohmmeter at the Collector of the
transistor is as low as 5 ohms I do not see why the rig does not key? Try
just a plain resistor to see what it needs on the rig. I bet over 100 ohms
would still key it.
>
> my ptt circuit uses RTS from the cw serial
> port, goes through a 4k7 resistors, then
> in parallel with a diode and another 4k7
> before hitting a 2n2222.... and then a
> final diode before having a PTT + and a
> ground line.
>
> Any ideas? tnx
>
> Steve, n9oh
>
>
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