[Top] [All Lists]

[TowerTalk] Horizontal loop and ladderline project

To: <>
Subject: [TowerTalk] Horizontal loop and ladderline project
From: (Tom Rauch)
Date: Fri, 20 Jul 2001 16:24:56 -0400
> Are there any issues with running 450 ohm ladderline in PVC pipe
> underground?  True open wire line would probably be best (like W7FGs), but
> I'm not sure how to "discretely" bring it back to the shack.

There are problems with that. A few years ago, I measured the loss 
in ladder line in buried PVC pipe. I don't have that data handy, but 
the loss increase is very substantial.

As I recall, placing the line inside PVC and then burying the pipe 
for ten feet caused loss to exceed that of even very small coaxial 
cables. There is substantial energy outside the area of the 
conductors in a balanced line, and unless you can suspend the 
line several conductor spacings (several inches) away from dirt you 
will likely find you have a nice load resistor. 

Of course the attenuation depends on the distance the line is 
buried, what the soil is like, and the spacing from the soil to the 
line...but I could even measure additional loss just from the PVC 
pipe with the line and pipe in air!

Unless you can put a tuner at the antenna and bring coax into the 
house, you may not have made a good bargain.

73, Tom W8JI 

List Sponsor: Are you thinking about installing a tower this summer? Call us
for information on our fabulous Trylon Titan self-supporting towers - up to
96-feet for less than $2000! at 888-833-3104 <A 

FAQ on WWW:     
Administrative requests:

<Prev in Thread] Current Thread [Next in Thread>