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- Subject: Re: [IRCA] Coax Cable
- From: Mark Connelly <markwa1ion@xxxxxxx>
- Date: Tue, 29 Jan 2019 05:44:48 +0000 (UTC)
- Delivered-to: irca@xxxxxxxxxxxxxxxx
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No one has yet mentioned the other feedline option: balanced line.
This takes many forms including speaker wire, two-conductor AC line cord (zip cord), TV twin lead, ladder line / window line, twisted pair, CAT-5 etc. Characteristic impedances are often in the 100 ohm range but will go higher for more widely spaced lines, e.g. 200-500 ohms.
Dallas Lankford's articles recommend balanced feed rather than coax.
https://www.okdxf.eu/index.php/technika/80-antenarska-kolekce-dallase-lankforda
I have been using speaker wire on moderate length runs (under 60m / 200 ft.) with negligible loss below 5 MHz. Appropriate matching transformers are used to minimize loss. If you have "critter" problems, you can run through garden hose or conduit. Most of my runs are a bit above ground. Water ingress hasn't been a problem. Falling tree branches .. well that's another matter I suppose.
Whether you use coax or balanced line, common mode chokes may be advisable on longer runs especially on low-signal-output antennas.
Mark Connelly, WA1IONSouth Yarmouth, MA
<<
Good to see that we've opened the flood gates on this topic, James.
Rodent bites have never been an issue at my coastal location in
western Canada, and I forget that it can be a big issue elsewhere.
OT:Â Â Â It's not like we don't have rodents, but perhaps they're all
fat and happy from the continual feeding they get here from little
old ladies of all ages and as many genders as floats your
boat....they think they're feeding just the fluffy squirrels and the
cute little chickadees.
The day I saw, in broad daylight, six large rats working a bird
feeder a few doors down made sure that I was never going to feed the
wildlife, no matter how senile I became. On the other hand, no
rodent bites on the coax....
best wishes,
Nick
At 12:35 2019-01-28, Mike Irizarry wrote:
>I use rg6 flooded for all my low band receive antennas. I usually get it
>from dx engineering. I have had very good success with it in the midwest
>buried and just on top of the soil. The flooded capability has mitigated
>small rodent bites. Some of the antennas I use it with are: 4 square, k9ay,
>beverage, bog, and dhdl.
>Hope this helps. It is not cheap, however.
>
>Mike
>
>On Sun, Jan 27, 2019 at 10:06 PM Nick Hall-Patch <nhp@xxxxxxxx> wrote:
>
> > Haven't seen any response to this, James, and am probably not going
> > to be much help.
> >
> > I've just used RG58 variants for up to 100' in permanent
> > installations around the yard, 10 to15 years in some cases. One of
> > them runs through about 70' of rigid PVC electrical conduit IPEX
> > #032907 and is buried. Mind you, I've heard that although such
> > conduit will keep the groundwater away from the coax, water vapor
> > will condense inside, leading to a wet interior anyway. That coax
> > still seems to work,so maybe it's dry...or maybe not.
> >
> > On DXpeditions, I've run over 500' of RG58 coax to DKaz'es and such,
> > and not suffered particularly.
> >
> > best wishes,
> >
> > Nick
> >
> >
> > At 22:26 2019-01-27, James Niven wrote:
> > >I am curious as to what type of coax everyone uses for DKAZ antennas and
> > >also general international shortwave band listening dipoles?
> > >
> > >It's time to revamp my antennas and I want to use the right cable that
> > will
> > >last for a while.
> > >
> > >
> > >
> > >I have read that RG-8U is good for long runs of a 100 to 150 feet, and if
> > I
> > >was to bury my coax, which is the best pipe/conduit to use to bring my
> > >cables into the shack?
> > >
> > >
> > >
> > >thanks
> > >
> > >
> > >
> > >James Niven
> > >
> > >Austin, Texas>>
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