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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[RFI\]\s+USB\s+qrm\s+\-\s+what\s+to\s+do\?\s*$/: 17 ]

Total 17 documents matching your query.

1. [RFI] USB qrm - what to do? (score: 1)
Author: Pete Smith N4ZR <n4zr@comcast.net>
Date: Mon, 13 Mar 2017 07:31:36 -0400
My shack computer has 6 different USB devices attached. When I disconnect all but the keyboard, it cuts the background noise level on 160M by a whopping 25 dB, from S9+18 down to S8 (as monitored by
/archives//html/RFI/2017-03/msg00019.html (7,373 bytes)

2. Re: [RFI] USB qrm - what to do? (score: 1)
Author: "David Harmon" <k6xyz@sbcglobal.net>
Date: Mon, 13 Mar 2017 08:31:49 -0500
I use Logitech wireless keyboard and trackball.....no cables....no problems. 73 David Harmon K6XYZ Sperry, OK My shack computer has 6 different USB devices attached. When I disconnect all but the key
/archives//html/RFI/2017-03/msg00020.html (8,130 bytes)

3. Re: [RFI] USB qrm - what to do? (score: 1)
Author: "Dave Hachadorian" <k6ll.dave@gmail.com>
Date: Mon, 13 Mar 2017 07:00:40 -0700
Page 10 of K9YC's Noise Suppression Manual suggest 7 turns on a 0431177081 Snap-on for 80/160. I think 7 turns will fit in there. I've got an HDMI cable with 5 turns, and it looks like I could jam tw
/archives//html/RFI/2017-03/msg00021.html (9,956 bytes)

4. Re: [RFI] USB qrm - what to do? (score: 1)
Author: "Wes Attaway \(N5WA\)" <wesattaway@bellsouth.net>
Date: Mon, 13 Mar 2017 09:11:37 -0500
Pete ... does every device add noise, or is it a specific device? Maybe you have done this, but you didn't specify this in your post. I would unplug them (and/or turn them off) one at a time, and the
/archives//html/RFI/2017-03/msg00022.html (9,606 bytes)

5. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Huff David J <HuffDavidJ@JohnDeere.com>
Date: Mon, 13 Mar 2017 14:22:53 +0000
I use a USB optical isolator. Starting at $36 online. https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG/ref=sr_1_1?ie=UTF8&qid=1489414739&sr=8-1&keywords=usb+optical+is
/archives//html/RFI/2017-03/msg00023.html (8,418 bytes)

6. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Chester Latawiec <chetlat@hotmail.com>
Date: Mon, 13 Mar 2017 14:25:36 +0000
Pete. I ran into a similar issue. It was not the individual USB devices, but rather the USB provider (the PC board with the USB plugs which allowed the USB cables to be plugged in). It appeared in my
/archives//html/RFI/2017-03/msg00024.html (10,689 bytes)

7. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Matthew King - KK4CPS <KK4CPS@gmail.com>
Date: Mon, 13 Mar 2017 10:27:40 -0400
Pete - I had similar problems until I purchased shielded USB cables with the small ferrites already molded in. The ones I have are silver and look braided under a clear insulation. They are noticeabl
/archives//html/RFI/2017-03/msg00025.html (10,831 bytes)

8. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Robert Nobis <n7rjn@nobis.net>
Date: Mon, 13 Mar 2017 07:48:04 -0700
Pete, Besides using quality shielded USB cables, make sure that your computer is also separately grounded to your common station ground with a one inch ground strap. In other words dont rely on the g
/archives//html/RFI/2017-03/msg00026.html (9,047 bytes)

9. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Gary Smith via RFI <rfi@contesting.com>
Date: Mon, 13 Mar 2017 09:19:19 -0700
How is your station grounded? Trusting the old "attach it to the water pipe, that'll be fine"? Sounds like ground looping to me. Most ground looping problems, to me this is what your describing, can
/archives//html/RFI/2017-03/msg00027.html (10,558 bytes)

10. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Mon, 13 Mar 2017 10:15:14 -0700
There is no such thing as a "ground loop." Most ground looping problems, to me this is what your describing, can be cured by going back to the basics. That is, a 6 or 8 foot ground rod driven into th
/archives//html/RFI/2017-03/msg00028.html (11,042 bytes)

11. Re: [RFI] USB qrm - what to do? (score: 1)
Author: JW via RFI <rfi@contesting.com>
Date: Mon, 13 Mar 2017 17:22:50 +0000 (UTC)
Better 'grounding' ... I like. It means even greater "displacement currents" are induced in equipment when said equipment is in the high-intensity E-field of the antenna (maybe twenty or thirty feet
/archives//html/RFI/2017-03/msg00029.html (12,408 bytes)

12. Re: [RFI] USB qrm - what to do? (score: 1)
Author: "Barry Merrill" <w5gn@mxg.com>
Date: Mon, 13 Mar 2017 15:45:08 -0500
K9YC states: Shielded cable rarely solves RFI problems, partly because to do anything useful cable shielding must continuous with equipment shielding, and lots of equipment to which you would like to
/archives//html/RFI/2017-03/msg00031.html (11,919 bytes)

13. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Parker Dinkins <parker@masterdigital.com>
Date: Mon, 13 Mar 2017 15:59:54 -0500
Shielding is part of the specification for USB cable. Parker W5ADD _______________________________________________ RFI mailing list RFI@contesting.com http://lists.contesting.com/mailman/listinfo/rfi
/archives//html/RFI/2017-03/msg00032.html (12,807 bytes)

14. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Steve <steve65@suddenlink.net>
Date: Mon, 13 Mar 2017 17:34:31 -0400
Do common, run-of-the-mill USB cables have shields? The USB page on wikipedia says a shield for the data pair is part of the USB specification. Just wondering if cheaper cables omit the shield? I see
/archives//html/RFI/2017-03/msg00033.html (12,427 bytes)

15. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Mon, 13 Mar 2017 15:10:57 -0700
Hi Barry, It's always best to use high quality cables with a good shield when they are available, but as noted, they only solve problems when the connector on the equipment they're plugged into is pr
/archives//html/RFI/2017-03/msg00034.html (13,692 bytes)

16. Re: [RFI] USB qrm - what to do? (score: 1)
Author: Jim Brown <jim@audiosystemsgroup.com>
Date: Mon, 13 Mar 2017 15:15:28 -0700
That's hard to know without cutting one open. :) Unbalanced audio cables SHOULD be shielded, but I remember seeing cheapies where the "shield" was a wire, or was a spiral shield (not very good for RF
/archives//html/RFI/2017-03/msg00035.html (10,394 bytes)

17. Re: [RFI] USB qrm - what to do? (score: 1)
Author: "KD7JYK DM09" <kd7jyk@earthlink.net>
Date: Mon, 13 Mar 2017 16:46:53 -0700
I had RFI from a computer installation in a basement to an antenna 135' away rendering HF useless. I determined it was coming from the wiring. I wrapped chokes (loops of wire, as done since the 1800'
/archives//html/RFI/2017-03/msg00036.html (8,415 bytes)

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