Ok, i'm attempting to attach a JPG of my
circuit. Hopefully the reflector doesn't
strip out attachments automatically. :)
Its actually a NPN 2n2222 transistor that
i'm using. See attached diagram.
You mentioned to use a PNP if "positive
keying" ... not sure if that is my case or
not. Rig is ic706mk2g. digging out the
--- Gil Baron <email@example.com> wrote:
> > -----Original Message-----
> > From: firstname.lastname@example.org
> > [mailto:email@example.com]On Behalf Of
> Steve Woodruff
> > Sent: Friday, November 08, 2002 8:57 PM
> > To: firstname.lastname@example.org
> > 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
> Be certain the Transistor is a PNP if Positive
> Be certain the correct polarity is used from the
> 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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Steve Woodruff, N9OH @ 42.18N 88.34W, email@example.com
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