120 foot tree mounted omni / Q's

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SPEEDCO

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Quick Question before I goto work.
(Please do not expend too much time/energy with your response.)
My house has dense trees approx 120-150 tall occluding 90* to 180* E to S
I want to mount an omni ant (single monopole and maybe omni scanner type) in a treetop approx 120' tall.
Cable length will be approx 120' plus another 150' to house.$
And, cable will need to be protected from line munching predators.
And.. i guess.. a 120' ground cable.. running down the tree..$
And....hopefully.. the ants wont need service anytime soon bc of height...
What are some of the quick pros/cons/thoughts....?
Will leave posted til I return from work. 2000hrs pst. today
thanx
Bill
 

mmckenna

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Overall: Pain in the rear.

Trees move around a lot, they flex, they grow, etc. That will cause issues in the long run.
270 feet of coax is going to be a major issue. Cheap/inexpensive coax will lose the great majority of your usable signal before it makes it to the antenna or to the radio.
Coaxial cable capable of getting a usable signal over 270 feet is going to be -very- expensive, you'd be looking at 7/8 inch heliax or better. That's measured in the dollar$ per foot range, so easily looking at $1000 or more just for the cable. Each connector is going to run between $20 and $40 or more.
If underground, you'll need conduit. That'll mean trenching. That'll mean lots of back breaking labor and more than a few cases of beer.
Even then, water will get in the conduit and Heliax isn't going to like that in the long term.
You'll still need lightning protection before it enters the house. That's going to be $50 or more per protector, plus the grounding, etc.
Running a 120 foot vertical run is going to require some additional work:
-Cable will need to be supported well, the sheer weight of 120 feet of 7/8" heliax is going to damage something.
-Cable will need to have it's outer shield grounded near the top, at the bottom and a few places on the downward trip.

Sounds like a headache in the making, probably because it is.

Will it work? Sure!
But it's going to cost a lot, require frequent maintenance and will not last as long as doing a proper install.

Unless you really need that 120 foot altitude, you'd be better off scaling it back.

If you really DO need that 120 feet, then you would probably be better off with a tower. At least that way you could eliminate 300 feet of coaxial cable.
 

trap5858

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There are many things to consider with this type of installation. I am sure I will miss some.

The length of feed line is quite long so you are likely to lose a lot of signal in the line. The larger the coax the less line loss and if looking to monitor uhf systems you might not have any signal left by the time it reaches your receiver. You might need an amplifier but they have pros and cons.

Another thing to consider is grounding and lightning protection. This is a very important consideration for your safety and the safety of your house and equipment.

For dealing with critters munching on the cable on the ground you can run it through fairly inexpensive PVC conduit

The last thing I would question is how do you intend to get this rig up that high? Trees that tall are a challenge for a professional arborist. Attaching the mast to the tree will also present some hoops to jump through as you do not want to damage the tree.

Good luck and let us know what you decide to do
 

jonwienke

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Get a tower. It will be less hassle, you will have a much shorter coax run, and you will be able to ground it properly. And you won't have to worry about tree branches rubbing against the antenna and damaging it or shorting it out.
 

JPSan

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Critters love to munch...

FYI: A acquaintance of mine ran his coax in a PVC tube, 3/4" diameter, the squirrels had a field day gnawing through the PVC and the coax in less than a months time.

 

JPSan

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The worst thing....

Had my share of radome damage from migratory geese punching through em.
Talk about a friggin' mess. Try cleaning that up. Thank the Maker we had people that assisted us. Usually had it happen 2 or 3 times a season on our various hops.
 
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