[Elecraft] [OT] Zip Wire Misrepresentation?

[Wes Stewart]

The number of tragedies in my life suggest otherwise, but in this case, I must 
live a charmed life.

I have never had RFI issues while using zip cord for speaker wiring in and 
around my ham shack.  I have used the red/black stuff for DC wiring but lately 
I'm using 10 AWG wire made for low-voltage landscaping use.  I also use it for 
connecting the speakers in my audio/video system.  The only downside is that the 
insulation is very thick since it's appropriate for direct burial and I have to 
shave it down a little to get it into the abysmal Power Pole connectors that are 
standard on too many devices these days.

Wes  N7WS

  On 8/11/2016 10:11 AM, Jim Brown wrote:
> Over the years, I've bought some of the red/black zip cord at hamfests. While 
> I have not measured any of it with a micrometer, my strong impression has been 
> that it IS smaller than labeled.
>
> More to the point -- zip cord is TERRIBLE cable for loudspeaker wiring because 
> it has very poor RF rejection. It has been well known for more than 120 years 
> that twisted pair has quite powerful  rejection of all interference, from a 
> few Hz to high RF. Think about it -- for the first 100+ years of telephony, 
> telephone wiring ran EVERYWHERE on the same poles as 60 Hz power lines with no 
> interference. Their ONLY measure to reject 60 Hz was to have the telephone 
> lines cross over each other every few poles along the run. This was enough of 
> a twist when the only interference was 60 Hz. Even today, there are huge 
> quantities of telephone, intercom, and even audio wiring carried on unshielded 
> twisted pair. CAT5/6 carry high data rate signals on opposing pairs without 
> interference. At tutorial lectures, I've demonstrated ordinary CAT5 providing 
> RF rejection as good as shielded twisted pair into the high VHF range. And 
> I've solved more than a dozen instances of RFI to home entertainment systems 
> simply by replacing glorified zip cord with twisted pairs of #12 POC (plain, 
> ordinary copper).
>
> For the same reason, twisted pair is superior for power wiring in our stations.
>
> As to resistance -- I use the shortest practical runs of #10 between my power 
> source (a big 100Ah LiFePO4 battery) and my two K3s. I do this because like 
> most 12V radios, it's cleaner (lower levels of key clicks) at higher supply 
> voltages.
>
> 73, Jim K9YC
>
> On Thu,8/11/2016 8:21 AM, rick jones via Elecraft wrote:
>> I just bought 20' of what was supposed to be 10GA zip wire from that auction 
>> site. It is clearly marked as "Audiopipe 10 Gauge speaker cable". The 
>> conductor is actually 12GA at best. Is this becoming common practice or is 
>> wire going the way of 2X4 lumber? Suggestions for a reputable source of true 
>> 10GA PTFE zip wire for K3 power?
>
>
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