[Antennas] Twin lead 450 Ohm

2002年12月11日 09:00:23 -0800

In reply to ladder line in a pvc pipe - I ran my line in a 2 inch pvc pipe
about 50 feet in my basement - through the wall of the house and then about
25 feet underground to a center support for a triangular antenna. The
horizontal portion was about 8 feet off the ground and the top point about
25 feet in the air. I loaded the horizontal portion a bit and was able to
operate over the top portion of 80 meters and on up in frequency.
How much loss did I have -- don't know but all worked fine.
73/Jim/AC4CZ
----- Original Message -----
From: "van lincoln wd8aam" <[email protected]>
To: "Mike J Maloney" <[email protected]>; <[email protected]>
Cc: <[email protected]>
Sent: Wednesday, December 11, 2002 1:49 AM
Subject: Re: [Antennas] Twin lead 450 Ohm
> I have run 1.5" spacing ladder line thru my basement cinderblock
> wall inside 2" pvc pipe, a couple of wood slats kept the ladder line
> centered, and I used paper towels to stuff the ends up, and it
> worked fine.
>> wd8aam
>> At 09:05 PM 12/10/2002 -0600, Mike J Maloney wrote:
> >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 )
> >>
> >>
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