Open wire feeders and proximity to other metal ....
 

OK .... here is another newbie question :)

I want to run an open wire feed to a 160M Dipole .... I need to bring
the feed in and across my basement. I want to run along the floor joists
but like most basements there are pipes and duct work all over.

What would be the minimal acceptable separation between other metal
object and the open wire feed???

For an idea of what I'm up against:
http://pabut.org/feedline.jpg

Thanks,

de ka2pbt

Open wire feeders and proximity to other metal ....
 

think coax. or put a balun at the entrance to the house and go coax from
there.

"Rob Roschewsk" wrote in message
. ..
OK .... here is another newbie question :)

I want to run an open wire feed to a 160M Dipole .... I need to bring the
feed in and across my basement. I want to run along the floor joists but
like most basements there are pipes and duct work all over.

What would be the minimal acceptable separation between other metal object
and the open wire feed???

For an idea of what I'm up against:
http://pabut.org/feedline.jpg

Thanks,

de ka2pbt

Open wire feeders and proximity to other metal ....
 

Rob Roschewsk wrote in
:

OK .... here is another newbie question :)

I want to run an open wire feed to a 160M Dipole .... I need to bring
the feed in and across my basement. I want to run along the floor
joists but like most basements there are pipes and duct work all over.

What would be the minimal acceptable separation between other metal
object and the open wire feed???

For an idea of what I'm up against:
http://pabut.org/feedline.jpg

Thanks,

de ka2pbt

Hi:

The rule of thumb I've heard is 2 times the wire spacing is the minimum
but I would just get it as far away as possible. Just remember with a
high SWR on the line there could be a high voltage node almost any were
on the line which can be a RF burn or a fire hazard so try and keep it
way from people and things that can burn. If you don't run high power
(200 watts) one way to handle the problem is to use an auto tuner
outside the house and run coax into the house. There are ones available
for high power but they cost a great deal. Some one will suggest a balun
and coax to the tuner in the shack. This can work if the coax is quite
short (12') as the SWR on the coax could be quite high and the loss due
to high SWR could be a problem. I've done this also and it works too.
The auto tuner outside gets by the high SWR problem as the coax is
working in the matched condition and will have low loss.

John Passaneau W3JXP

Open wire feeders and proximity to other metal ....
 

I want to run an open wire feed to a 160M Dipole .... I need to bring
the feed in and across my basement. I want to run along the floor
joists
but like most basements there are pipes and duct work all over.

What would be the minimal acceptable separation between other metal
object and the open wire feed???

For an idea of what I'm up against:
http://pabut.org/feedline.jpg



So far, no one has mentioned using a short section of balanced coax.
Rather than using baluns and a single coax, you could use two lengths of
coax to get past the metal. Use the center conductors of both parallel
pieces, and just connect the two shields together. You will still have
high losses in the coax, but shouldn't be significant if you keep the
coax run short. Doing it this way will at least avoid the possible high
voltage node / fire hazzard problem of having open ladderline near wood
and metal fixtures, and also avoid needing to use baluns.

good luck.

Ed K7AAT