Fw: Fw: Fw: Re: [Antennas] 450 Ohm Ladder Line
Sandy and Kees Talen
[email protected]
2002年12月16日 22:15:25 -0600
I still want to make the balun loss measurements for the one in the
tuner, but I'm rapidly coming to the conclusion (30Mhz anyway)
.......for my situation which is a 250ft run to the antenna with plenty
of trees .....that:
1) a full run of RG8 foam coax has about a 40% loss (a run of
RG58 foam coax has a 70% loss) ......50% loss is 3dB, 20%
loss is 1dB. Easy to run, medium cost.
2) 1/2" hardline where I can use it (RG8 for the rest) would have
a total 28% loss. More difficult to run and attach to, high cost
unless you can get it surplus.
3) a full run of 450 ohm window ladder line has a 12% loss (plus
balun losses). Low cost, work to modify, little more difficult
to run, fun to use.
4) a full run of 450 ohm window ladder line has very large losses
when wet/damp (on the order of 70% for modified line and 82%
for unmodified line). Modified line when dry has a very slight
improvement over unmodified, too small to warrant the work.
5) the old open wire 4"-6" spaced ladder line is not as affected by
moisture but is a pain to make and run.
Note: all the data above is based on a 250 ft transmission line.
73 Kees K5BCQ