On Jun 25, 12:29*pm, Michael Coslo wrote:
dykesc wrote:
I'm going to 450 ohm window line to my OCF Dipole. Obviously, as
confirmed by EZNEC, without some kind of choking action at the
feedpoint, my feedline will be radiating. What kind of 1:1 choke could
I use on the 450 ohm line at the antenna feedpoint? I could build a
1:1 choke with the right toroid but not sure if I can maintain the 450
ohm line Z0 through the choke.

I'd let the feedline radiate. It's a part of the package.

Also, is there a reason that you wouldn't use coax instead of window
line? Your impedance on amateur frequencies should be such that a 4:1 or
6:1 balun at the (off) center point then a run of coax should work well.

* * * * - 73 de Mike N3LI


Hi Mike

I modeled a 4:1 at the feedpoint in EZNEC. I would need 100 feet of 50
ohm line. Loss on RG-58 at 3.7 Mhz is 3.25 db. At 28.3 Mhz loss is
4.7db. Those are "best swr" frequencies for those bands. Operation on
either side of them results in even greater loss. Similar results on
other bands. RG-8 cuts the losses in half but the variation in SWR I
mentioned makes that a still unacceptable option for me. No amplifier
here so conservation of power delivered to the antenna is important to
me.

73
Dykes (AD5VS)