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Re: [RFI] Re-wiring station

To: rfi@contesting.com
Subject: Re: [RFI] Re-wiring station
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Fri, 30 Dec 2016 13:49:52 -0800
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
Twisted pair is always a good thing to minimize crosstalk. That red/black zip cord is expensive junk, and the stuff I see at ham flea markets and sold by various vendors online is often a couple of wire gauges smaller than advertised.

It is easy to buy suitable lengths of white and black stranded THHN (house wire) at your local big box store, spool out equal lengths, stick one end of both conductors in a bench vise, the other in hand drill, and twist it slowly until you have a lot of turns per inch. Turns/inch is not critical, but more yields greater rejection to a higher frequency.

Twisted pair made this way won't be uniform from end to end, but that isn't a big deal. When I do this, I let it sit overnight to "remember" its twist. It will still untwist a bit, but not enough to matter. I mostly use #10.

Using twisted pair for power can be quite important if the DC or low frequency AC current is noisy, as it usually is between a solar panel, the charge regulator, and the battery(ies).

Also, the slides for a talk I've done at Paciifcon and for several ham clubs on Power, Grounding, Bonding, and Audio for ham radio have a lot of useful advice on how to set up and wire your station to minimize hum, buzz, and RFI, while also providing maximum lightning protection. It's the ham radio version of the 4 hour workshop I did for ten years for sound and video contractors at major trade shows until I retired a few years ago.

http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC

 On Fri,12/30/2016 1:29 PM, Chuck Gooden wrote:

Currently getting back into ham radio and re-wiring my station. I would like to eliminate as many spurious signals as possible. Does it make sense to put the red and black zip cord used for DC power feeds in a drill to twist it to reduce and cross talk and coupling of stray signals? If so how do you determine the number of twist per foot for effective results?
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