If the ladder line is 450 ohms, and well matched at the operating
frequencies, Palomar makes a nice 9:1 transformer that goes balanced
450 to unbalanced, I think three 150 ohm lines around a core. In
series on hi side, in parallel on low. I use one of these on the
ladder line out to my 40 m sloping folded dipole I use for stateside.
Along with a 300 ohm matching section out at the folded dipole, I get
1.3 to one or less over entire band. Once lost the connection at lower
end of the folded dipole and the SWR went 9:1 or something like that,
so it's efficient. 280' run out to there. I have the transformer
grounded.
If it's a "tuned" line, not balanced, and you're within 10-15 feet of
where you can bring the ladder line, then RadioWorks makes a "Remote
Balun", which is constructed with the application in mind. Their web
page has a fair amount of explanation on the issues.
Lacking that, a good grade RG11, with two lines in parallel, shields
connected together and grounded both ends if possible, use the two
center conductors to hook to the ladder line. (When I was with AT&T in
TV and Microwave, we used 130 ohm balanced line extensively. It was
two 70 ohm coaxes underneath the same outer cover.) Suggest you not
use foam or 50 ohm coax for this.
If you do this there are possible length issues, and you may get RF in
the shack anyway if the current on the ladder line is seriously
unbalanced. It *can* be tricky, so this is no silver bullet, but it
might work for you, and it gets away from nearby metal and RF
interference sources in the shack.
Good luck.
On Mon, 26 Apr 1999 05:40:03 PDT, you wrote:
>
>
> I would like to replace the coax from my cloud burner loop with
>Ladder Line. I have looked through the Handbook and other antenna
>books and have found information on running ladder line past/over
>large metal surfaces (roofs etc). But I have not found any practical
>info on running it once you get inside the house ?
>
> I live in a raised ranch style house with the shack in a front
>room and the antenna's out back. I could bring the Ladder Line into
>the house about 6 feet off the ground and run it in between the
>floor joists
>then up through the wall to the shack. This run will be about 18'
>long and I was planning on using 2" plastic conduit to house the
>line. This route however will pass within about 24" of several
>fluorescent lights and some other house wiring. Will this be a
>problem ?
>
>Thanks in Advance
>
>Jim Apple - WB1DOG
>
>_______________________________________________________________
>Get Free Email and Do More On The Web. Visit http://www.msn.com
73, Guy
--. .-..
Guy Olinger, K2AV
k2av@qsl.net
Apex, NC, USA
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