[CQ-Contest] Keyboard RFI problem solved

Don Cassel ve3xd at rogers.com
Thu Aug 18 14:31:20 EDT 2005

I had the same problem a couple years ago but I was only running low power.
Toroids on the keyboard cable did help but did not eliminate the problems.
Actually it took me a while to figure out that it was the keyboard.
Eventually I found the same solution as you by switching keyboards from a
second computer which used a MS USB keyboard. Problem gone without any need
for toroids. 

73, Don VE3XD

-----Original Message-----
From: cq-contest-bounces at contesting.com
[mailto:cq-contest-bounces at contesting.com] On Behalf Of Bill Turner
Sent: Wednesday, August 17, 2005 11:15 PM
To: rtty at contesting.com; cq-contest at contesting.com
Subject: [CQ-Contest] Keyboard RFI problem solved

I've been playing around on 160 meter RTTY the last few days and had a
problem with the keyboard freezing when the power exceeded a certain level,
around 1kw output. I tried three different keyboards and enough ferrites on
the keyboard cable to anchor a battleship but no luck. In fact, no
improvement at all. And that got me to thinking: Why didn't the ferrites

Perhaps the problem isn't in the keyboard at all, but rather the connection
inside the computer, since all three keyboards had exactly the same
sensitivity to the power level, and adding ferrites made no change in the

Long story short: I happened to have a USB keyboard laying around, so I
tried it. Presto! Problem solved, perfect operation at any power level. I
can't say this would work in every instance, but it's worth a try. The
keyboard is just an inexpensive one made by AOpen.

One problem with this is the BIOS does not recognize a USB keyboard, so it
must be set to not stop on keyboard errors, and if you want to hit DEL to
set the BIOS, you have to temporarily plug in a regular keyboard.

Something to keep in mind if you have keyboard RFI problems.

Bill, W6WRT

CQ-Contest mailing list
CQ-Contest at contesting.com

More information about the CQ-Contest mailing list