[Antennas] Twin lead 450 Ohm

2002年12月10日 21:05:17 -0600

A very good question, one which I would bet very darn few(if any) have
actually tested. This came up some months ago in a side thread about
running ladder line into the shack. Most said any buried ladder line
would have great loss. I dont see really why it should unless the pipe
should become full of water which could be quite likely if care was not
taken to prevent it. It would make for a good experiment, but before I
went to 10 inch PVC with the line centered, I would try 2 inch centered
and non-centered and work up to 4 and 6 inch to see if any detectable
difference between this and loss in air. Even in 2 inch PVC it would
seem to me that most of the dielectric between and surrounding the
conductors would still be air and plastic? If the dielectric of the
buried line in PVC is changed, it should be quickly detectable as a
change in the electrical length at a given frequency as compared to being
in open air. This is my speculation on the subject. It would be my
thought that the most difficult part of making this practical would be
keeping the inside of the PVC full of air or even better DRY air. What
lower loss coaxial line is there than one with dry gas such as nitrogen
under positive pressure being most of the dielectric? I cant see why
coax of this type would be much different in attenuation or losses than
that of open wire line, perhaps even better? 
73, Mike ac5p
On 2002年12月10日 07:15:38 -0800 (PST) Honest Charlie's Used Cars
<[email protected]> writes:
> 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?
>> =====
>> When I was a kid I was so naive, I would go 
> behind the barn and do nothing.
>>>>> Twas a woman who drove me to drink, and I 
> never had the courtesy to thank her for it. 
> W. C. Fields ( 1880 - 1946 )
>>> __________________________________________________
> Do you Yahoo!?
> Yahoo! Mail Plus - Powerful. Affordable. Sign up now.
> http://mailplus.yahoo.com
> - - - 
>> Your moderator for this list is:
> Larry Wilson KE1HZ [email protected]
> _______________________________________________
> Antennas mailing list
> [email protected]
> http://mailman.qth.net/mailman/listinfo/antennas
>