[1000mp] Re: PTT keying

[ve3yv at pathcom.com]

This has been on the reflector before, with several possible solutions.  My
experience with an opti-isolator was also that it didn't close the PTT line and
then added a resistor in parallel.  Think it was around 50 ohms, found by
experiment - picked the next highest value in the junk box to the one that
closed the PTT.  Another approach to avoid modifying a commerical interface is
to wire the resistor in a RCA plug and plug into the PTT jack - I forget the
call of the author of that one - somewhere in the archives. 

Hope this helps.

73,  George  VE3YV / K8HI
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 25 May 2005 19:40:32 -0400
> From: "Tom Homewood" <w1to at adelphia.net>
> Subject: Re: [1000mp] ptt keying current ?
> To: "All about Yaesu 1000mp" <1000mp at mailman.qth.net>
> Message-ID: <009a01c56183$24823410$0200a8c0 at Work>
> Content-Type: text/plain; format=flowed; charset="Windows-1252";
> 	reply-type=original
> 
> This is pretty close to what I measured, in fact I think I measured a little
> 
> more current.
> 
> I could not sink this with an opto coupler. I went to a discrete transistor.
> 
> 73, Tom, W1TO
> 
> 
> ----- Original Message ----- 
> From: <zoltan.pitman at vodafone.com>
> To: <1000mp at mailman.qth.net>
> Sent: Monday, May 23, 2005 5:20 AM
> Subject: [1000mp] ptt keying current ?
> 
> 
> > Hello all,
> >
> > Can someone pelase tell me how much current flows (should be flowing) when
> > PTT is shorted directly? I measure 13.7V when it is open, and 9mA when it 
> > is
> > shorted.  I have plain vanilla MP.
> >
> > I suspect something has happened inside because the keying transistors 
> > needs
> > to be opened much more to key the radio.
> >
> > thanks,
> >
> > zoli ha1ag
> 
> 
> 
> 
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> End of 1000mp Digest, Vol 13, Issue 17
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