Thanks for the replies, guys it was a real education.

I have an indoor dipole cut for 20M that is 4:1 SWR at it's most resonant
part of the band. If I drop one leg to the ground, the swr drops to near
1:1, but the rf is everywhere, including the lcd display of the rig.

I run it with the high swr and a tuner, but the indoor location and hilly
country are not kind. Even so, I do get a weak signal onto the band.

Are the dangers to the coax cable independent of how well you match the
antenna/feedline to the rig?


--
Powered by Linux 2.6.32.14-127 Fedora 12
"No spyware. No viruses. No nags." 2.6.24-16 Mint Elyssa
In rotation: http://www.jamendo.com 2.6.31.12-0.2 OpenSUSE 11.2

On 9/19/2010 8:28 AM, Rockinghorse Winner wrote:
Thanks for the replies, guys it was a real education.

I have an indoor dipole cut for 20M that is 4:1 SWR at it's most resonant
part of the band. If I drop one leg to the ground, the swr drops to near
1:1, but the rf is everywhere, including the lcd display of the rig.

I run it with the high swr and a tuner, but the indoor location and hilly
country are not kind. Even so, I do get a weak signal onto the band.

Are the dangers to the coax cable independent of how well you match the
antenna/feedline to the rig?



It has been a while since I did voltage calcualtions but a lot depends
on your cable.. You use coax designed for 2000 or 5000 watts, and feed a
4:1 antenna with a 100 watt transmitter.. NO PROBLEM coax wise.

You use coax with a 250 watt power rating.. You gonna have problems with
a 4:1 on a 100 watt transmitter. Just what the cut off is.. I don't
know.


--
Nothing adds Excitement like something that is none of your business.

"Rockinghorse Winner" wrote

I have an indoor dipole cut for 20M that is 4:1 SWR at it's most resonant
part of the band. If I drop one leg to the ground, the swr drops to near
1:1, but the rf is everywhere, including the lcd display of the rig.

I run it with the high swr and a tuner, but the indoor location and hilly
country are not kind. Even so, I do get a weak signal onto the band.

Are the dangers to the coax cable independent of how well you match the
antenna/feedline to the rig?

Assuming you're running no more than 100w and your coax is RG58 or larger,
there is no danger to the coax at 4:1. (Actually, you shouldn't be running
even 100w when using an indoor antenna.) I would try a different
orientation for the antenna and get it further away from nearby objects. To
me, the fact that you've got no better than 4:1 in its, um, "current"
configuration, tells me something's wrong with either its placement, its
dimensions, or its construction. Is the coax hanging straight down from the
feedpoint? If not, that could be part of your problem.

Howard N7SO