[Elecraft] Possible firmware regression related to ACC2 IO / PTT=LO

[Wayne Burdick]

Mark,

When the KX3 is placed in transmit mode, it doesn't disable its RX I/Q  
outputs. These come directly from the receive mixer. Since the KX3's  
local oscillator is still active in transmit mode, too, a really  
strong signal (one that gets around the T/R switch) could still give  
you a strong enough response at the I/Q outputs to be decoded. It  
might vary with relative positions of the equipment, cables, etc.

You should be able to prevent the decode by putting the KX3 into SPLIT  
mode, with VFO B moved well out of the target band. This way the LO  
would be shifted in transmit mode so that any decode would be out of  
the range of Skimmer.

For example if you're on 20 meters, set VFO B to well below the band  
edge, say 13.8 MHz.

Let me know if this works.

73,
Wayne
N6KR



On Dec 16, 2012, at 5:13 PM, K7MJG wrote:

> Wayne,
>
> Thank you for taking the time to reply on a weekend.
>
> I'm not an EE, so I could have flubbed this test, but here is what I  
> did:
> With ACC2 IO PTT=LO, KX3 power output set to 0.0W, and CW Skimmer  
> monitoring
> the RX I/Q from the KX3, I plugged a brand new plug into the end of  
> the
> short ACC2 cable supplied with the 'KX3-PCKT Cable Set' (no  
> connection to
> the 590), then shorted the tip to the sleeve. The KX3 TX light came  
> on as
> expected.  I keyed up a short dit on the 590 at five watts (into a  
> dummy
> load, for the record) and was able to see the dit show up on the CW  
> Skimmer
> screen at the 590 TX frequency.
>
> Curiously, when I went to the KX3 right after reading your post, I  
> could not
> immediately recreate the behavior.  With no intentional change to  
> the setup,
> it started happening again, which is when I did the experiment above.
>
> Let me know how you'd like me to proceed.  I can try to load older  
> versions
> of the firmware, but I'll wait for your recommendation.
>
> 73,
> Mark Glenn
> K7MJG
>
>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/Possible-firmware-regression-related-to-ACC2-IO-PTT-LO-tp7567198p7567268.html
> Sent from the Elecraft mailing list archive at Nabble.com.
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