[Lowfer] Wm beacon testing tonight @ JAY

[John Andrews]

Charlie,

Conductor loss in a loaded vertical is not usually the big issue, unless 
you have the ground and environmental losses really nailed (not possible 
for most of us). So the Litz wouldn't be a lot of help.

Transmit loops are another matter, though, due to the inherent low 
resistances involved. Radiation resistance is best expressed in 
micro-Ohms, so conductor resistance and environmental losses are important.

Bill Ashlock definitely did experiment with Litz wire on his backyard 
loops. The results were initially very promising. But Litz is fragile -- 
the tiny strands are easy to break, and the constant motion in the trees 
is a big problem. To protect the wire, he used garden hose (or something 
similar). That did help keep the water out, until moisture began 
condensing inside the hose. But it could not keep the strands from 
breaking with all of the swinging around.

 From an August, 2002 email from Bill: "I'm at a Q of about 200 with 
both the Litz cable and 1/2" cu pipe. The soil loss at the moment is 
about .22 ohms and probably won't improve more than a few 100ths. 
Therefore the limiting Q would be under 500 even if the conductor had a 
0 ohm Rac. This wouldn't pose much of a handicap for CW operation - 
nothing like the Qs in the thousands that the guys operating loops in 
the HF Ham bands experience."

He gave up on the Litz fairly quickly, and went with the copper tubing. 
Not cheap (especially these days), but if you silver-solder the fittings 
and keep the copper thieves away, it works darn well. I never saw that 
loop -- Bill said it didn't look very pretty, though. He just kept 
soldering sections together and hauling them up into the trees.

This brings up one additional point. Bill had the correct concept of a 
vertical loop: maximize the height, and provide the minimum amount of 
conductor near and parallel to the ground. His concept of the best xmit 
loop was to shoot a line over a single tall and wide tree, or maybe two 
trees close to each other. Trees with big canopies at the top were 
preferred. I've deftly ignored this advice, hence the limited 
performance of some of the antennas!

John, W1TAG