Direct bury coax suggestions??

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VE3TMT
Posts: 99
Joined: Wed Apr 07, 2004 12:50 am

Direct bury coax suggestions??

Post by VE3TMT »

I have intentions to build a 150' vertical delta loop this spring. The antenna's apex will be up in a maple tree in my backyard at about 60', with the ends going to each corner of my yard about 15' above ground. I am going to feed it with coax through a 4:1 balun. My plan is to run the coax out the basement wall (I already have a run of RG213 there for my R7) down to the yard and buried along its run out to the back of the tree about 35'. From there it will run up the backside of the maple to the balun. I am not going to be running more than 100W to the loop and need suggestions on some coax that can be buried direct as the roots of the tree will make it hard to bury some PVC pipe.

Thanks,

Max
VE3TMT
WA9WVX
Posts: 103
Joined: Tue Aug 09, 2005 2:31 am
Location: QRZ Indicates Northern Illinois

Burying 50-Ohm RF coaxial cable

Post by WA9WVX »

Hello Max,

I don't know if you have a semi-local 2-Way Land Mobile Radio Shop or a Commercial Tower Installation Company in your area. Some times these shops and Tower companies have removed pieces of 1/2" Andrews 50-Ohm Heliax cable that they are willing to sell to the general public. The Heliax RF cable is a very low loss RF coaxial cable that can be directly buried in most any type of soil. You shouldn't pay more that $.50~$.75 per foot for used cable with the connectors included. If the Heliax was installed correctly when it was originally put into use, this cable will last almost indefinitely unless it was hit by Lightning or the Heliax connectors were incorrectly installed.

On the other hand if you don't have the money for used Heliax then I suggest looking at the Davis RF Cable web page for Direct Bury 50-Ohm RF cable:

http://www.davisrf.com/ham1/coax.htm

In either case use Coaxial Seal on the RF connectors to prevent moisture from getting into feedline and destroying the 50-Ohm Impedence.

73,

Dan
WA9WVX
k9yli
Posts: 229
Joined: Fri Aug 12, 2005 11:35 pm
Location: northwest wisconsin

bury coax

Post by k9yli »

In northern country frost is a problem.
Direct bury andy wire and frost wil heave and try to stretch it.
ooops...
Minimum is bury in loose sand. put some S bends in it to allow stretch.

Cheap and easy is get some black poly pipe at the farm store or big hardware.

bury the pipe shove the coax thru.
Remember in the pipe carry a drill with about a 1/8 inch bit.
after laying out pipe in trench, drill a hole on the bottom in any low spots,
as moisture will accumulate and needs to be drained.
make big sweeping bends if you change direction and also going into the ground and coming out.
Easier to shove coax thru it.
Price diff is small so think big,, like inch or inch and 1/4 , then you can shove coax thru with connectors on it.

poly pipe is in the 20 $ range when new hardline would be 300.. range. per 100 feet.
5/8 poly used to be around 7 bucks for 100 feet.
so inch is likely around 30ish by now.
still cheeeeep compared to PVC and easier to work with.

makes cheep 5/8 garden hose too.
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