Fw: Fw: Fw: Re: [Antennas] 450 Ohm Ladder Line

[Charles Greene]

I use LMR-400 for a 100' run to a vertical in my yard. It is direct bury 
LMR-400, so I will bury it in the Spring.  It has less loss than RG213, and 
I'm going to try it direct buried and see if the loss goes up.  It's 
supposed to work.  When I use RG213, I usually put it inside PVC tubing so 
it won't be contact with the ground.  I've  had a piece of RG213 buried 
inside PVC tubing for 15 years and it hasn't deteriorated.  Not so for RG8 
which gets moisture through the outside covering.  The cost of direct bury 
LMR400 is less than the cost of the RG213 plus the PVC tubing.

At 10:15 PM 12/16/2002 -0600, Sandy and Kees Talen wrote:
>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
>- - -
>
>Your moderator for this list is:
>Larry Wilson KE1HZ antennas-owner@mailman.qth.net
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73, Chas, W1CG
K2 #462