[Elecraft] Neat K3 Video! - K3 Amp interface questions

[Doug Faunt N6TQS +1-510-655-8604]

   From: "Joe Subich, W4TV" <w4tv at subich.com>
   Date: Mon, 3 Dec 2007 14:58:57 -0500


   Jerry, 

   > I am presently using a method in which my PC reads the rig freq and 
   > generates band-data signals for the amp ( 
   > http://www.ab4oj.com/quadra/w4uk.html or 
   > http://mywebpages.comcast.net/rwilliams309/QUADRA_interface.html ). 
   > This works OK, but always requires the logging computer is on and 
   > that the program is running.

   It's a non-issue. Both the Quadra and FL-7000 have internal pull-ups. 

   Further, the TopTen and microHAM Band Decoders include pull ups 
   on their BCD inputs.  The only device that I know of that lacks 
   the pull-ups is the Unified Microsystems (W9XT) BCD-10 decoder. 

That's useful information.  If the K3 band select lines can tolerate
12V pullups, then it'd be trivial to add the 4 resistors to the
W9XT board....(time passes on the internet)-

It looks as if the band select lines are driven directly from a
TPIC6C595, and the outputs of that can drive as high as 33V to
ground.  Some of you should check my work, but I think the problem
is trivial.  4 10k resistors on the W9XT board, and Bob's yer uncle.
And I have one the W9XT boards in my hand, and it'd be pretty easy to
add a 5V regulator, if you wanted to, also.

TPIC6C595 data sheet- http://www.ortodoxism.ro/datasheets/texasinstruments/tpic6c595.pdf

And if the polarity is wrong, then that can be changed in the
firmware.

Much flap about not much.  But I've learned from it.

73, doug