[Top] [All Lists]

[TowerTalk] computer rfi

To: <>
Subject: [TowerTalk] computer rfi
From: (Roger L. Elowitz)
Date: Tue, 15 Jul 1997 00:46:07 -0400
Hi Scott,

Glad to hear of your success with the rfi elimination project.  You
probably could have gotten a better video monitor cable as we tend to think
all these cables are alike and they really aren't.  Some are vastly better
than others.  I have snap-on ferrite beads on every cable coming in or out
of the computer and the monitor. On some cables I have two or even three
ferrites. I can operate 2-kw and absolutely nothing happens to my monitor
screen now. My monitor is sitting right up against my Kenwood TS-440  and
Yaesu 901 DM exciters and the linear is only 18" away. 

As for the moles.... I ran over one today with my riding lawn mower.
(Darn!)  He was probably dead anyway before I squished him. 

And as for the birds.... I thought the guys were kidding when they
mentioned using plastic owls to scare away the birds. Then the other day I
flew into a small airport here in NJ and there on each wing of a small
private plane that was tied down.... were two- foot high plastic owls.

It was explained to me that birds love to nest in orifices like the engine
air intakes and tail-fuselage openings. The owls give them second
thoughts....for their little birdbrains. Planes are really for the
birds.....OUCH! as Steve would say!

Roger, K2JAS 


At 02:24 AM 7/15/97 +0000, you wrote:
>Hi esteeemed towertalkians, This is a follow-up to a previous posting
>today..... Well, I got itchy tonite after picking up some emi/rfi paint
>($19.00 per can), I took my monitor apart-it was already coated with some
>emi paint-even measured the resistance-right up to spec-7 ohms per inch, I
>recoated it completely anyways, as the can I got said multiple coats were
>more effective.
>For anyone that is contemplating doing this, make sure you take it OUTSIDE
>before you paint it!  This stuff has Methyl Ethyl Ketone in it-serious
>stuff-also good buzz for those of you that like to sniff the stuff-IT'S
>At the same time, I took the monitor video extension cable off, I found that
>the interference would come and go when it was unplugged from the pc, even
>if the monitor wasn't connected! I cut the extension in two pieces, slid on
>a full length of rg-8 shield and two MAMBO beads, resoldered it together,
>heatshrinked, etc, and plugged it all back in-grounded the new shield to the
>pc case, and also connected other end of the extension with short solid wire
>to the metal monitor video connector. Voila!!!!!!!!!!!!!!! No more
>One of the worst frequencies for receiving the crap was believe it or not
>14.195.0   It is now completely quiet!  Also powered up the SB200 and ran
>full key down on each antenna-no herringbone/squigglies at all! Maybe this
>monitor won't go kablooie like the last one did from rf!
>For those of you that have this problem, give this a shot, it only took me
>about 1.5 hours even playing with different grounds before I hacked up the
>cable to install the shield. Definitely worth the time, maybe now I will be
>able to hear the next DXpedition better on that frequency.
>Also fyi, the monitor is 1.5 feet above the ts-930, and the cable runs down
>through the bench directly behind the amplifier output, and the computer is
>below the radio by abt 1 foot. I would think this is a worst case scenario
>for any monitor/computer!
>73 to all, hope this was a help to those that needed it, email me direct if
>you have any questions.
>P.S. the smell of the emi paint is enough to scare the birds and the moles
>away for good!  :)
>FAQ on WWW:     
>Administrative requests:

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>