[PVRCNC] May 1 PVRCNC Meeting

[Jim Jordan, K4QPL]

Reading the "teaser" for the PVRCNCEBQSO party, I'm not sure whether I'm 
relieved or sorry I'm missing this meeting! But I sure am curious about what 
it is.

I did want to give a follow up on the Altoids tin pocket SO2R interface 
which was my show and tell a couple months ago. I ran into a problem in 
which the PTT line would drop out when computer generated cw started.  Got 
busy with other things and left it on the shelf for a while, but now after 
much trouble shooting and experimentation all is once again well.  The 
problem appears to be excessive current draw by the generic NPN switching 
transistors.  We're only talking milliamps here, but using the 1 k pull up 
resistor as specified for a 2N2222 allows the open circuit 5V "high" to be 
knocked down to well under 1V, barely enough to key the line. The additional 
voltage drop from cw keying also sinking through LPT Pin 1 apparently pushes 
the PTT line over the edge and the "switch" opens.  I've experimented with 
resistor values from 2 k to 10 k on these Radio Shack transistors, all of 
which solve the problem with no apparent side effect on keying and showing 
closed circuit values on the 'scope of 1.5 to 2.5 V.

In the near future I'll tidy up the schematic and circuit board layout and 
make it available for anyone who wants it. Cool thing is that even if you 
don't use SO2R, you can have a pocket interface with cw, ptt, rx focus, tx 
focus and foot switch capability for home, portable, guest op or field day 
use for under $30. Try buying a DX Doubler or microHam product for little 
more than their shipping and handling charges!

73,

Jim, K4QPL
----- Original Message ----- 
From: "Roberts, Will" <will.roberts at pgnmail.com>
To: <pvrcnc at mailman.qth.net>
Sent: Wednesday, April 30, 2008 8:15 AM
Subject: [PVRCNC] May 1 PVRCNC Meeting


Mark your calendars for tomorrow night at Manchester's at 6PM. It's
already May and time for the next exciting PVRCNC meeting. As contesters
we are naturally a competitive lot.  Tomorrow's meeting will feature
competition x 2 with Paper Contest guru N4TL's next challenging edition
PLUS the debut of the first (annual?) PVRCNC Eyeball QSO Party. Members
will compete head-to-head (literally) in an in-person contest where the
guy or girl with the biggest lungs (rather than the biggest antenna)
will win. Both contests feature valuable prizes, although the EyeballQP
prize will not have the special  W0UCE style wrapping!



Your normal contest toys will not help you in the EQP, however your
contesting skills just might. You are advised to bring your favorite
writing instruments and a clipboard or notebook in order to write while
standing. This promises to be a fun night where you may get to know the
other members just a little bit better. We hope to see you all there -
bring a friend...



73,



Will AA4NC



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