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Author Topic: RF proof computer  (Read 1803 times)
K0RMK
Member

Posts: 2




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« on: October 31, 2001, 05:25:14 PM »

Does anyone know who makes an RF shielded computer?
If so, I would like to order one.
My Gateway makes noise on my rig and my IC 746
makes noise on my speakers; the computer has also been crashing more since I set up my base station.
Tech support at ARRL has not responded.
Sincerely,
Roger
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K0PSK
Member

Posts: 1




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« Reply #1 on: November 04, 2001, 08:16:42 PM »

Try a laptop!

73
k0psk
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K3AN
Member

Posts: 787




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« Reply #2 on: November 04, 2001, 10:39:58 PM »

Yes, try a laptop.  My IBM Thinkpad 760 series generates no HF QRM whatsoever, and it doesn't crash when connected to the 100 W HF rig. I use a COM port for CW keying, and my PSK-31 connection is two cables between the rig's headphone and mic jacks and the computer's audio jacks. I had to wire series dropping resistors to get the audio levels in the proper range, but there's no DC isolation whatsoever. Even the Thinkpad's switching power supply seems to be RF quiet.

The only situation where a laptop will be inadequate is where you need multiple COM ports to key the rig, and control it, and control an antenna switcher, etc.

It will be interesting to see how soon the rig and ham accessory manufacturers migrate to USB, as "legacy" COM and parallel ports (and even keyboard and mouse ports) slowly disappear in the next couple of years. Inexpensive USB hubs will let users connect a whole lot of peripherals before running out of bandwidth.

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W9GB
Member

Posts: 2616




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« Reply #3 on: November 06, 2001, 10:03:18 PM »

There is a german company that makes a computer case that appears to be (as is marketed to be) RF shielded.

NOT a cheap case, finger stock, metal jumpers.  A local computer firm (run by a amateur) did have a couple.  I believe that a few broadcast radio stations had ordered them and "RF quiet" switching power supplies.
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WB0UGO
Member

Posts: 5


WWW

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« Reply #4 on: November 11, 2001, 12:38:06 PM »

I have a small business where I make a lot of custom built computers.  The problem with a Gateway is they use a less expensive power supply and and are very propriatary.  You might try a good Enlite or INWIN case
if you can fit your Gateway components in it, which could be  a problem.  Also use torroids on the video
and I/O leads on the computer.  I have 5 computers in the house and shack and RF is no problem even when using full legal power. Good luck, 73's  Steve
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W4HTX
Member

Posts: 1




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« Reply #5 on: November 14, 2001, 08:43:26 PM »

You may also want to check on the monitor when you get RFI on the rig from what seems to be the computer. If you are running Windows, you can go to the advanced settings for the monitor and tweak the vertical refresh rate, which is OFTEN the overlooked cause of QRM/QRN on 20m and other HF bands. Change the refresh rate  and see if the 'noise' moves with the change. If it does, you may be able to quiet it down when needed. You can also do a quick check by manually turning off the monitor. If the noise drops out, you may be able to pursue the fix I mentioned. It's a workaround, but in many cases, it works. To get to it, right click on the desktop where no icon is, in the open area. Then click PROPERTIES, and then look for the SETTINGS tab, then look for the ADVANCED button. Different versions of Windows may require slight changes. (I use Windows 98 SE).
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KC5YDR
Member

Posts: 1




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« Reply #6 on: December 11, 2001, 01:56:35 PM »

After fighting this for several weeks on my new computer I came across a new Power supply. It cured the Noise!!!! I went from a 10 over noise level on all bands too nothing with this one swap. I found the P/S on www.pricewatch.com look for "low noise" or "Noise Killer” prices range from $10.00 + Shipping and up. Hope this helps.

Mike
KC5YDR
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N2GEG
Member

Posts: 2




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« Reply #7 on: December 21, 2001, 05:52:18 PM »

I am looking for amplified computer speakers that are RF shielded - one set I have here has RF get right into the amplifier - same level of noise when I'm keyed up on HF regardless of speaker volume setting.  

Do any of the Ham manufacturers make a set of amplified computer speakers that are shielded?

73 de Mike, N2GEG
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N4HRA
Member

Posts: 281




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« Reply #8 on: December 23, 2001, 02:22:52 PM »

Get your self a bunch of RS Snap-together Ferrite Core PN 273-105.
Place 1 at Each end of the keyboard cable (this cable generates the most noise)

Place 1 on each cable going to the computer
This is what I did and their is no computer noise in the radio and the radio does not interfer withthe computer
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K4KEP
Member

Posts: 1




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« Reply #9 on: December 28, 2001, 08:14:10 AM »

I CAN NOT REMMEMBER THE NAME OF THE LAPTOP COMPUTER USED EXTENSIVLY BY THE GOVERNMENT BUT I THINK TANDY BOUGHT THEM SEVERAL YEARS AGO.

IT WAS EXTREMLY QUIET RATED FOR USE IN SECURE GOVENMENT AREAS AND AVAILABLE SURPLUS.

SORRY I CAN;T REMMEMBER THE NAME. IF I HEAR IT I WOULD REMMEMBER IT.
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KC8RYW
Member

Posts: 75


WWW

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« Reply #10 on: December 29, 2001, 10:00:36 PM »

IN ALL KINDNESS, K4KEP, PERHAPS A QUICK TAP OF THE CAPS LOCK KEY WOULD BE A GOOD IDEA.

73 KC8RYW
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N0SYA
Member

Posts: 366




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« Reply #11 on: January 20, 2002, 10:09:27 AM »

Font Police??
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If you have a clumsy child, you make them wear a helmet. If you have death prone children, you keep a few clones of them in your lab.
W4CNG
Member

Posts: 178




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« Reply #12 on: October 05, 2002, 05:40:42 PM »

Laptop, proper grounding, ferrites on all in/out cables, and that should fix most issues.  My only issue left is full power on 75 meters, tears up my laptop, and the bypassed phone lines.  I tell all to not use the phone while I talk on 75 meters with the Attic Antennas.  All other bands are no problem.
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KB0NLY
Member

Posts: 1




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« Reply #13 on: October 13, 2002, 11:45:55 PM »

Seems to be a lot of YELLING IN THIS FORUM. HI HI

But seriously, there are manufacturers of shielded cases.  I have used them with great success building computers over the years.  Just make sure no matter how much you spend on the case and the components inside that you pay for a quality power supply!

Scott, KBØNLY

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