[Antennas] Buried window line

[Wes (N7WS) and Linda]

As a newcomer to this forum (Thanks Danny, K6HME) I've been trying to get
up to speed using the archives.

In one message Honest Charlie's Used Cars  chas_east@yahoo.com wrote:

"Opinions Please...If 450 later line was suspended in
the center of a ten" PVC pipe and buried would it have
the properties of one suspended in Air?"

As best as I could follow along there were a number of answers which I will
not repeat.

My first thought though is a question, "Why would you want to?" 

Window line (my preferred nomenclature) has the following advantages
compared to coaxial lines:

1) Lower cost
2) Lower weight
3) Potentially lower loss under mismatched conditions

It also has the following disadvantages:

4) Radiation from the line unless balance is carefully maintained (extra loss)
5) Requires a balun in the system (more loss)
6) Increased loss when contaminated by foreign material, especially water
7) Needs to be kept separated some distance from other objects
8) More fragile

Note that unless 4, 5, 6, and 7 are addressed, 3 may not be realized.

Returning to the original question my simple answer is "more than likely".

However, from a systems viewpoint I think the realization would take heroic
effort unless the run is very short.  The cost is certainly going to
increase to the point that that advantage is long gone.  The weight is a
non-issue, at least for the underground part.

The part about "suspended in the center of" is likely to be difficult to
achieve. 

Unless the parameters are widely different from what I imagine my
suggestion would be to use a length of 7/8" Heliax and be done with it.

Wes  N7WS