[RFI] Re-wiring station

Jim Brown jim at audiosystemsgroup.com
Fri Dec 30 16:49:52 EST 2016

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.


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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