Tree as Mast?

[CSL126]

I just wanted to get some opinions on using a tree as a mast for an antenna. Assuming that I can find some type of insulated material to mount it to the tree, would this be ok? Currently the antenna is mounted about 40 ft high on a mast attached to my house. Placing it in the tree would probably put it at about 80-90 ft high. A local tree climber said that he could climb one of the trees in my yard and hoist it up on a rope. This setup will only be for receiving. I figured that I'd also buy some LMR400 feed line. I am by no means an expert, so any comments would be appreciated. Thanks!

 

[RadioDaze]

Make sure you have slack in the cable to allow for swaying of the tree.

 

[texasemt13]

I've assisted some other amateur radio operators on a few tree installs. Not a bad idea. We found straight trees and flat topped them as high as we could before the tree bent, and used it as a pedestal or mast to get the antenna higher. If you're leaving the tree intact, try to separate it from the tree a little (assuming the antenna is a vertical), and insulate it. Depending on the tree type (low moisture + high density wood), you might not have to worry too much about insulating.

As RadioDaze said, leave slack in your feed lines, and any ground plane radials (if any). Unplug that feed line from your receiver during storms.

 

[reedeb]

I know up in Maine many would put an Antron 99 up in the tops of a tree [150 -200 feet] Many would get out great.

 

[radioman2001]

I have used them before as a means fo getting an antenna up there, just lightning protect it. A tree is a fair attractor for lightning, but when you run a wire down it, you basically have a lightning rod.

 

[DPD1]

The hard part is fixing the cable so it is secure, but at the same time, doing it in a way where the cable does not get stretched, or damaged from abrasion when the bending occurs.

 

[mike_s104]

Remember that trees grow out as well as up, so you may need to do some adjustments after a few years.

 

[SCPD]

Seen this a few times

I think a tree works well if you use mast pipe from the ground up, and tie the mast near the top with a strong loop of rope or heavy hose clamp. Don't make the rope or clamp tight. Like another said, your tree is going to grow, and your tree is going to sway, so keep the tie off to the tree loose. But from the different intalls I have seen using a tree, it works better with one long mast pipe from the ground as close to the middle of the tree, as opposed to mounting the mast to an upper branch. Plus this way keeps the antenna more vertical.

 

[N5JBD]

Tree as a mast

Go for it, I live in the country and love wire antennas for my ham radio station. All are running through trees the longest 576 feet.

Just remember that trees move and bend and take that into account when installing it.

Enjoy!

 

[ridgescan]

Also remember that once it's up there-it's up there. If you have to enlist a tree climber to put it up, then I assume you'll get him to take it down anytime it needs attention? If you get an antenna with awesome materials that stand up to weathering well like the d130j, then you can set it and forget it for many many years. Same with the coax-your 400 is good for weathering. Pics when you have it up there please

 

[Daniel_Boone]

First off - I have to agree with Radioman2001 in the fact that putting something metallic on the top of a tree is a real good way of making a lightning rod.

There is no real good way to establish a ground plane in a 90' tall tree.

Second off - if all you are going to do is LISTEN, you do not have to use 50 ohm cable.
There is no reason to spend good money on transmission line if all it is going to be used for is receiving.

The key here is that you did not specify the frequency with which you are trying to receive.
All wire looses a specific amount of signal - expressed in DB per 100 ft.
27 mhz in a RG 6 Belden 7916 Quad Shield wire, the loss in 100 feet is probably only 1.5 db
The loss at 900 mhz might be as much as 6 db....

 

[SCPD]

This thread has me thinking. Anybody have this kind of install with photos? I have a few trees that would work for me.

 

[Daniel_Boone]

I just wanted to get some opinions on using a tree as a mast for an antenna. Assuming that I can find some type of insulated material to mount it to the tree, would this be ok? Currently the antenna is mounted about 40 ft high on a mast attached to my house. Placing it in the tree would probably put it at about 80-90 ft high. A local tree climber said that he could climb one of the trees in my yard and hoist it up on a rope. This setup will only be for receiving. I figured that I'd also buy some LMR400 feed line. I am by no means an expert, so any comments would be appreciated. Thanks!

First you want to use a tree for a mast for your antenna, then you want to use expensive wire for your antenna.

Trees has many downfalls - such as the fact that they sway when the wind blows.
They rot and they can make even galvanized bolts rust when you install it.

Trees also make an excellent lightning rod because the tree is not a conductor and it sounds to me as if it is as tall as everything else in the neighborhood and your goal is to get your antenna above everything else without spending any money.

The only thing that i can say is that it isn't my antenna or my house.
I wouldn't want to live in your house though after you do it and the lighting comes down your coax and into your shack and takes a whole bunch of junk out with it.

You don't need LMR 400 for a receive antenna.

You can do the same thing with RG 6 quad shield or even some left over cable from the cable company - the silver stuff they use to go pole to pole - since they throw away lengths that are too short - under 100'.
That stuff makes excellent conductor for a receive antenna because it is very low loss and it is 72 ohm - which is no big deal because you aren't going to broadcast on it anyways.

 

[zz0468]

Disregard Daniel_Boone's advice. Trees make excellent antenna supports. A heavy ground connection from a ground rod to the antenna mount can be installed along with the feedline, and the usual grounding practices that are done on tall antenna structures can be done. As mentioned, keep in mind that trees sway and move around, and they grow.

Further disregarding Danial_Boone's, your choice of feedline should be based on your performance requirements. There are on-line loss calculators that will show you how much loss there is for given cable types, lengths, and frequency ranges. It then becomes a cost-benefit decision. Always buy the best quality, lowest loss cable you can afford.

 

[kb0nly]

I don't have any pictures but i know of one antenna install thats up in a old pine tree, its been up there so long that the tree's bark grew over and around the coax. Ever seen a tree incorporate a fence? I have on the farm, it happens with enough time. Anyway, its been up there so long that they literally had to pull more coax from the excess they coiled in the building near its base, good thing they didnt cut it short! As the tree grew they just let it haul up more coax. Nothing like a tower that grows itself taller! LOL

You do need to get serious about lightning protection though. I would suggest a well grounded coaxial arrestor at the base of the tree and multiple ground rods for good grounding. Other than that no worries, the tree doesn't make any better of a target than a tower when it comes to lightning, they are all susceptible.

 

[LtDoc]

Trees are very common antenna supports, usually are cheaper than other things, and also have 'faults'. Of course, it depends on what purpose you have for that antenna. I have used trees for a long time in a number of locations to good effect. For whatever reason, if you can't use another type support, trees do very well.
- 'Doc