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Home > Archive > Home Repair forum > January 2006 > Direct Burial Of Coax Wire ?
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Direct Burial Of Coax Wire ?
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| Robert11 2006-01-29, 10:21 am |
| Hello:
Can anyone offer an opinion on how well a good quality name brand coax
(going from house to a simple receive-only shortwave antenna in backyard)
will "typically" last if buried ?
Not the coax types called "buriable", just the regular stuff.
Will probably run in a pvc conduit, but was wondering about if I didn't.
Anybody have any experience with just burying the typical PVC covered coax
stuff about 6 inches or so deep ?
Think it'll last 10 years ?
Thanks,
Bob
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| If it's buried directly in the ground or in a conduit, it'll get just as
wet. If you don't want to buy direct burial coax, run it in a conduit to
make it easy to replace if it goes bad
"Robert11" <rgsros@notme.com> wrote in message
news:Gp6dnSGj2ZEmW0HenZ2dnUVZ_s6dnZ2d@comcast.com...
> Hello:
>
> Can anyone offer an opinion on how well a good quality name brand coax
> (going from house to a simple receive-only shortwave antenna in backyard)
> will "typically" last if buried ?
>
> Not the coax types called "buriable", just the regular stuff.
>
> Will probably run in a pvc conduit, but was wondering about if I didn't.
>
> Anybody have any experience with just burying the typical PVC covered coax
> stuff about 6 inches or so deep ?
> Think it'll last 10 years ?
>
> Thanks,
> Bob
>
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| hallerb@aol.com 2006-01-29, 11:21 am |
| I use Home depot coax, its under 50 bucks for 500 feet.
I put a temporary dish here and just buried the coax, it was a short
term fix that lasted a year till I trimmed a tree, longer than planned.
by a year the cable was bad, water got to it,
run in conduit of plastic pipe, its cheap and no digging needed if it
ever needs replaced.
if you run conduit and keep water out coax will last forever.
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| Bob Bob 2006-01-29, 11:21 am |
| See you everywhere Bob!
Generally speaking it wont last 10 years being buried on its own. Water
ingress is the killer. Unless you run a transmitter though you may not
even notice it for several years.
How long it lasts depends on many things like soil moisture, acidity and
even seismic activity!
I'll make some other comments on antennas in the other NG.
Cheers Bob
Robert11 wrote:
> Can anyone offer an opinion on how well a good quality name brand coax
> (going from house to a simple receive-only shortwave antenna in backyard)
> will "typically" last if buried ?
>
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| Don Allen 2006-01-29, 12:21 pm |
| l would strong suggest using a coax which has a non-contaminating
jacket. Normal PVC jacket's plastisizers leach into the dialectric over
time and increase attenuation. There are a number of direct-bury types
of coax available, including RG-213 which would be overkill for use
with only a receiving antenna. You can e-mail directly, and I will
give you some suggestions. Remove the NO SPAM from my address.
Don Allen
e-mail: w9cwNOSPAM@yahoo.com
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| If you are just going to use it for receiving, it won't matter if the
jacket rots and the shield braid corrodes. You mainly need an
insulated wire. I would give it even 20 or 30 years as long as you
don't drive over it.
Dick
On Sun, 29 Jan 2006 08:44:28 -0500, "Robert11" <rgsros@notme.com>
wrote:
>Hello:
>
>Can anyone offer an opinion on how well a good quality name brand coax
>(going from house to a simple receive-only shortwave antenna in backyard)
>will "typically" last if buried ?
>
>Not the coax types called "buriable", just the regular stuff.
>
>Will probably run in a pvc conduit, but was wondering about if I didn't.
>
>Anybody have any experience with just burying the typical PVC covered coax
>stuff about 6 inches or so deep ?
>Think it'll last 10 years ?
>
>Thanks,
>Bob
>
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| Bob Bob 2006-01-29, 2:21 pm |
| Disagree with you Dick
Corrosion starts on the outside surface of the wire and at RF
frequencies thats where most of the signal is carried (called skin
effect) This is the basic reason you use fatter cables and silver
plating etc at higher frequencies.
The dielectric will also become lossy with water ingress even if you
ignore the impedence change consequences. It becomes a resitive load in
other words.
The question you have to ask is how much loss can the RX system handle.
If the interest is in AM broadcast down around 1Mhz where the
atmospheric/manmade noise is stronger than anything the receiver noise
and cable loss will be, your method would probably be okay. At higher
frequencies though the margin becomes less and less to the point where
the natural "hiss" of the radio w/out the antenna is all you'll hear in
the absence of a "real" signal. For receiving you need a good signal vs
noise ratio.
Cheers Bob
Dick wrote:
>
> If you are just going to use it for receiving, it won't matter if the
> jacket rots and the shield braid corrodes. You mainly need an
> insulated wire. I would give it even 20 or 30 years as long as you
> don't drive over it.
>
> Dick
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