[WT-support] RFI and Wintest

Stewart GM4AFF stewart at gm4aff.net
Wed Mar 26 18:07:47 CET 2014

Hi Bob, thanks for the suggestions. I actually have 2 wireless and one wired
keyboard (+ 3 mice) in the shack, which (on my last PC) were all used on
different bands! Been there. Tried them all - but none would allow 6 band
problem free operation. I have ferrite beads on the wired keyboard. All the
mice are wireless.

I have got rid of the network cable (which did make a difference) and
replaced it with wireless. This got rid of the problem on 10m!

The only wire going into the PC are the radio CAT/serial cables. These have
ferrite on them.

PTT and CW keys are all good. I can turn up the power and the problem starts
at a specific power output fairly consistently. I have also bypassed all the
antenna switching with a amp-direct-to-the-antenna cable, and it still

I don't want to take up any more reflector space with this, but if anyone
else has any thoughts I'd really appreciate them - just send direct to me.

I will be trying Frank's opto-isolator idea.





From: support-bounces at f5mzn.org [mailto:support-bounces at f5mzn.org] On Behalf
Of Bob Wilson, N6TV
Sent: 25 March 2014 20:59
To: Win-Test Reflector
Subject: Re: [WT-support] RFI and Wintest


Try a different keyboard, maybe a wireless keyboard and mouse, or put
ferrite beads on all cables leading to the PC, as many turns as you can.
Mix #31 works well.


Of course make sure it's really RFI and not a configuration error.  Perhaps
the PTT and CW pins are reversed.  This will cause a key down carrier for
the duration of the message.


Bob, N6TV


On Tue, Mar 25, 2014 at 1:53 PM, Stewart GM4AFF <stewart at gm4aff.net> wrote:

I am having some problems with RF getting into my PC and upsetting the
WIntest keying. I can do what I like with the paddles when I run power, but
as soon as I touch a WIntest function key to send CW it just locks
everything up with a solid transmitted carrier. I was able to eliminate this
on my last PC by grounding the case and using WiFi, but not on this PC. It's
only bad on 15 and 40m. The 15m antenna is quite near the shack and the 40m
antenna has a bad SWR at the moment - so I know the cause.

Does anyone have advice on what can be done to prevent this - practical
down-to-earth solutions (excuse the pun).





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