[Elecraft] P3 TX Audio monitoring

[Alan Bloom]

On Wed, 2012-07-04 at 11:03 +1000, Gary Gregory wrote:
> *Well as nobody responded to my original post which identified a possible
> issue with my station setup which allowed the P3 to display live TX audio
> from the K3 ...

I should have copied the list on my previous reply to Gary.  (See below)

Alan N1AL

-------- Forwarded Message --------
From: Alan Bloom <n1al at sonic.net>
> Reply-to: n1al at sonic.net
> To: Gary Gregory <garyvk4fd at gmail.com>
> Subject: Re: Fwd: Screen Shots showing TX signal appearing on P3
> Date: Mon, 02 Jul 2012 10:07:08 -0700
> 
> Hi Gary,
> 
> The P3 is supposed to blank the screen whenever the K3 goes into
> transmit mode.  If that's not happening then it sounds like there must
> be an RS-232 communications problem between the K3 and P3.  One
> possibility is if you have some third-party software program running
> on the PC that is overloading the RS-232 capacity by sending large
> volumes of commands to the K3.  For example Ham Radio Deluxe is known
> to do that, depending on its settings.
> 
> If you want to see the IF leakage during transmit you can do that by
> disconnecting the RS-232 cable.  Another way is to change the "Xcvr
> Sel" menu selection to "8215 kHz (inverted)" instead of "K3".
> 
> I've been resisting making that an official feature because it really
> isn't very reliable.  It depends on random leakage through the mixer
> and PIN diode switches in the K3, which are unspecified.  It also
> varies with band and transmit power level and may result in too small
> a signal to be useful under some conditions.
> 
> The plan is to include a modulation monitor function with the future
> external power sensor option.  I've had the hardware done for months
> but have been too busy with the SVGA development to have time to do
> the firmware.  Real Soon Now.  :=)
> 
> Alan N1AL