Over the years I have built several Quadrafiliar antennas for 137.5 Mhz
polar orbiting weather satellite photos. I have the dimensions pretty
well refined to get horizon to horizon reception but they have all been
copper tube on a PVC pipe. I have some 3/8" stainless tube left from a
watermaker project and thought I might use it and a piece of Max-Gain
fiberglass tube to make one that would look nicer and hold up at sea. I
have a couple of questions about changing over to stainless but don't
know where to ask them.

The resistance of the stainless tube is the thing that worries me. The
balun design I came up with balances 1/2" copper tube to 50 ohms almost
perfectly but changing the diameter to 3/8" stainless is going to change
the impedance. I just don't know how much and in which direction.

There is plenty of info on the web about QHF but I can't seem to find a
newsgroup or forum to ask questions. Anyone else here dabble in
quadrafiliars?


--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com