[TowerTalk] Two elemenet Quad and baluns

[Craig D. Smith]

I've never built a multi-band quad, Dan, but have done several single band
loops and quads.  You will want a 2:1 impedance transformation at the feed
point (assuming 50 ohm coax) and also a conversion from balanced to
unbalanced.  As others have mentioned, an easy way to do this is to use a
1/4 WL (electrical) section of 75 ohm coax to do the impedance
transformation.  For the balun, I usually just tightly coil the 75 ohm coax
so that it serves both purposes.  You can probably obtain better balun specs
with ferrite, but I've found that the coiled coax works adequately in this
application.

73  Craig  AC0DS