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?
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
