[Elecraft] Seeking loop Antenna Parts

[Jim Brown]

On Wed,2/10/2016 4:41 AM, Don Wilhelm wrote:
> Clay,
>
> You should be able to find suitable pulleys and cord at a marine 
> supply store.

Pulleys yes. Cord at a marine store will be expensive.  Here's a link to 
the company that makes great antenna rope that is resold by several 
large ham vendors. 3/16-in is enough for strength, but 5/16-in is easier 
to grip if you need to pull it to put a lot of tension on it.

http://www.synthetictextilesinc.com/supportham.html

> I would recommend using hard drawn copper for the wire rather than 
> THHN.  You can find THHN at your local DIY store.  For hard drawn 
> copper, look at The Wireman www.thewireman.com.

The only issue with THHN is that it stretches if under load. I have high 
dipoles under about 100# tension, and I have to trim them every few 
years. Another way to do hard drawn copper is to buy #8 bare copper at 
your local big box store and stretch it yourself.  Cut a few hundred 
foot length, tie one end to a tree or telephone pole, the other end to a 
trailer hitch, and pull VERY slowly until it breaks. The result is hard 
drawn copper that is 15-20% longer.

Before you commit resources to a loop, take a look at the antenna 
planning applications notes on my website.   k9yc.com/publish.htm

In general, low horizontal antennas have poor efficiency. Antennas that 
lack common mode chokes at the feedpoint are noisy on RX, and it's not 
practical to choke most non-resonant antennas. If ground conductivity is 
good in your area, a roof-mounted multi-band vertical could be an 
excellent choice.  Study the FCC map. To choose a vertical, study the 
N0AX/K7LXC report on their measurements of the performance of a dozen or 
so HF verticals. Available from Champion Radio Products. Well worth the 
$35 or so that it costs. While you're there, also buy the report on 
tri-band Yagis -- you'll benefit when buying something to put on that 
tower when you get around to it. This work was done about 15 years ago, 
but the laws of physics don't change. :)  N0AX is now editor of the ARRL 
Handbook and the ARRL Antenna Book -- he's a fine engineer who really 
knows his stuff.

https://www.fcc.gov/media/radio/m3-ground-conductivity-map

73, Jim K9YC