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   Home   Help Search  
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Author Topic: 10 Meters and my Computer  (Read 897 times)

Posts: 80

« on: August 13, 2004, 07:32:08 PM »

DX has been really good to Europe and fair to South America the last several days here in Maine, so I thought I'd try other bands instead of 20 meters.

I'm working strictly PSK31. I tried all bands from 80 meters to 10 meters.

All was "just fine" until I tried 10 meters. As soon as I started transmitting, all kinds of crazy things started happening on my computer.

Windows were minimizing and maximizing, stuff was moving on my task bar and system tray. Obviously what was in ram was corrupted.

I had to do the "three finger salute" (which is the same as the "Microsoft Shuffle") to reboot as I could no longer control my computer nor could I make it unkey. I had to reach over and shut off the radio!

After the computer rebooted, all was fine, except the stuff that had "reorganized" it's location on my desktop. And that was easily fixed.

Here's the current setup. Computer first:

Barebones Soyo Athlon kit.

AMD XP 2100+ CPU
512 megs DDR ram
20 & 80 gig harddrives
DVD+ burner

Radio next:

Icom IC-706MkIIG
LDG AT-11MP Autotuner
6-80 meter dipole antenna

The tuner has a short (less than 6 feet) of RG58 coax to a 4:1 balun, which has about 3 feet of 450 ohm ladder line within the shack.

I don't think the balun looks very weather proof, or I'd place it outside of the shack with all the ladder line. The balun is also made by LDG.

So, it would be real nice to be able to work 10 meters when it comes back AND log with my computer.

Any (cheap, $-wise) suggestions?


David, N1ZHE

Posts: 1524

« Reply #1 on: August 13, 2004, 08:49:44 PM »

I've occasionally had the same problem on 10m.  Some frequencies in that band seem to be fine while others create havoc.  I suspect that the problem is that the 10m band is close in frequency to some key components in the computer.  I've found that I must minimize RF in the radio room.  This means a resonant antenna or near resonant tuned to the lowest possible SWR to minimize harmonics.  I cannot use my random wire antenna as there is just too much RF in the room then.

Posts: 559

« Reply #2 on: August 13, 2004, 09:29:52 PM »

You have a few years to sort this problem out.

Consider either making a ten meter antenna, or buying a used CB antenna.


Posts: 340

« Reply #3 on: August 13, 2004, 10:09:49 PM »

There are circuits inside your computer that 10-meter frequencies will affect. First thing to do is to install a proper ground. The key to this is a ground buss bar right behind your equipment. I use 1/2 inch copper plumbing pipe and hose clamps for attaching individual ground wires from each peace of equipment to that copper pipe. Do not get cheap and hook more than one peace of equipment to the buss bar! I have an antenna tuner sitting on top of my amplifier with a separate ground wire for each. It makes a difference as I tried going cheap and had problems running that way. Next route a very heavy and short wire or 1/4 inch copper tubing from the buss bar to your ground. Also hook the computer case and monitor (separate wires for each) to the buss bar. Next route coax horizontal and interconnecting cables vertical or as much as possible and separated as much as possible. Contrary to what a lot of people think ladder line will not radiate RF into a room as long as it's properly done. No conductors, metal cabinets or anything like that at least double the width of the ladder line. I have a 4:1 Balun mounted below my window inside with about a foot of ladder to the feed through insulators in the window. I also have about feet of ladder line from the 4:1 Balun in the antenna tuner that I can switch over and use when running the amplifier. With this setup I can now run a kilowatt and have no problems at all on 10 meters. I only tried it once; you really don't need that much power on 10-meters!    

Posts: 95

« Reply #4 on: August 14, 2004, 01:51:20 AM »

I'd suspect RF getting into the mouse or keyboard.  I'd pick the mouse as most likely.

Posts: 9749


« Reply #5 on: August 14, 2004, 04:09:05 AM »

More than likely the LDG balun is no good.

I'd replace it with a different balun, and see what happens.

Other than that you could try to move the balun outdoors and ground the coaxial shield of the cable feeding the balun with a very good RF ground, but I'm really pretty sure the problem you have is caused by a bad balun design. The only exception would be if the antenna was installed too close to the operating position or had the feeder parallel to the dipole element, etc.

Is the LDG balun a voltage-type balun? If so, get rid of it!!!

73 Tom

Posts: 176


« Reply #6 on: August 14, 2004, 07:56:41 PM »

Well, my computer starts going through all the monitor settings, and the smoke detectors go off when I transmit on 2, but I still have had problems on 10.  Is there any psk activity on 10?

Posts: 80

« Reply #7 on: August 14, 2004, 09:14:31 PM »

Nope. Found no psk activity at all but on 20.

Thought I'd give it a try, though, considering the recent sunspot activity and the upswing of some other bands.

David, N1ZHE
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