[ct-user] FW: help

Dio Dio" <diomar@electriciti.com
Sat, 30 Aug 1997 06:32:44 -0700

Hi Pedro,
I've had the same problems with my computers. "RF Infiltration"
I've tried washing it out, I've tried shouting it out...Nothing. 

One of the things that helped the most was replacing the keyboard.
I'm now able to bump the RF out on the TS940 to >100W. I don't know
how far from the antenna your computer is. You may have some
serious near-field problems that ferrite cores and grounding just
won't help.

First check to see how much RF the box/computer will take. NO!
Don't try to use it for a dummy load. PC's are not known as
effective radiators. Although, if you listen to every other bit of
RF squeaks and squaks that come out of it, you may say otherwise.
Turn off the PC and unplug all the wires from the computer except
the AC input, keyboard and monitor. Make sure the internal PC
speaker is plugged in. Turn the PC on and bring the PC up to a
'DOS' prompt. Unplug the keyboard and monitor.  How you do this is
your business, start bringing the RF up to a level that you may
start hearing clicking sounds from the PC speaker. RF @ max? No
sounds? Good! Plug in the monitor and try it again. No Sounds? Good
Plug in your keyboard. No Sounds? Are you sure the PC speaker is
connected? Still no sounds? Excellent! When you do find the errant
RF attracting component, ground it, ferrite it, shield it, or
remove it and try to find a replacement for it. 

Having a good ground is important. Grounding is your friend.
Bringing all components to that same ground potential is very
important. Don't daisy chain grounds. Every component gets its own
ground lead. No pushing and shoving that way, and no weird ground
line resonances. I can hear the holy wars starting re: correct
grounding techniques. It's ok...I wear Kevlar and Nomex briefs.

Aside from the keyboard, check the AC feed to your computer power
supply. If there is no AC input line filter, install one. The
CORCOM  line filters (N6KI recommended, KE6WEO tested, mother
approved.) work well. They are LC series and C to ground. You want
to mount the filter inside the PC(best) or on the shortest possible
pigtail from the outside(good). You might also want to wind the AC
input line around a ferrite ring. DON'T plug the monitor into the
back of the PC. That daisy chains the AC line making it longer and
negates the CORCOM on the AC into the PC. Long wires and HF don't
mix. Neither does dinking and driving and I've seen alot of dinks
on the road this weekend.

If none of this makes sense...Que Tal or Cest le vie or write me
back and let me know. I have lots of PC's and unix workstations
here and they suffer from the same problems. Your mileage may vary,
void where prohibited. Careful on that last one.

RFI. The scourge of the rabid DXer, contester, HFer, radio
operator. PC manufacturers should get as much grief as radio
operators for 'disturbing the peace'.

73 & GL DE KE6WEO . .
Merilly, merrily, merrily, merrily...


BTW: I don't work for CORCOM or the manufactures of Kevlar and
Nomex. I do believe in their products.

> From: Randy Thompson <k5zd@ultranet.com>
> To: 'CT Reflector' <ct-user@ve7tcp.ampr.org>
> Subject: [ct-user] FW: help
> Date: Friday, August 29, 1997 3:51 PM
> Can anyone offer Pedro some suggestions?
> Randy, K5ZD
> -----Original Message-----
> From:	Pedro Claver Orozco [SMTP:claver96@axisgate.com]
> Sent:	Thursday, August 28, 1997 9:24 PM
> To:	k5zd@contesting.com
> Subject:	help
>  hello randall,my name is pedro hk1hhx from colombia.
> congratulations for nice operations in a contest.
> randall i have a little problem,i put my ct 9 contest program and
i did try 
> a made a contest with it but the computer receibe much RF from
the radio 
> station and sometimes is imposible operate with computer.
> i put grounds i put filters and the problem continue.
> do you have something to help me in this case.
> say me something and tnx for all.
> your friend in colombia hk1hhx
> pedro
> --
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