Ice & snow on antenna wire

[Nashua Area Radio Society]

I’ve had long wire antennas up in my backyard for shortwave listening for several years. Usually I go out and smack the coax with a long wood rod to clear the ice or wet snow from the horizontal wire run.

Once last year the wire drooped from 30′ high down to about 7′. I was using a pulley & weight at one end. The wire bounced back up as soon as I smacked it with my wood stick. So, no stretch or damage to the wire.

But now that I have my General license, I put up a Buckmaster 7-Band OCF which I suspended from a 58′ high 160′ long messenger rope. I suspended it for two reasons. Buckmaster recommends the feed point should be 30′ high and the ends 10′ high. And secondly, upper tree limbs don’t give me enough clearance for the 135′ long OCF up where the messenger rope is located.

Since I didn’t have a practical way to use a pulley on the 160′ long messenger rope, I am letting it droop down about 10′ to accommodate tree sway. Then I have another short rope hanging down attached to the balun’s eye bolt. This puts the antenna feed point at 32′ high. The ends are 15′ high.

My concern is now that I have pulled the antenna ends tight to eliminate droop in the antenna legs, the messenger rope is essentially tight between the trees, even though it has a droop. Actually, the entire arrangement will be subject to the weight of ice and snow.

I’m sure there is a better way to have done this. Maybe a pulley at the antenna’s feed point? But I don’t really want a rope & weight hanging down in everyone’s way in the backyard. Any suggestions?

[Jwahar Bammi]

An alternate is to use a heavy spring on one end, Home depot has several. I used an old door spring at one time. Worked fine, accommodated the tree sway and weight of ice (snow does not stick around to be a consideration) quite well. This assumes your antenna wire/rope are both up to the job.

73 de k1jbd
bammi

 

[Nashua Area Radio Society]

I’ve got one end tied off at the base of the tree and the other through a pulley and tied to a screen door spring. With all the wind today I got to see it working. I’ve also got enough line at the spring end that I could lower the whole antenna down and back up for maintenance.

 

Just another idea.

[Nashua Area Radio Society]

Thanks for the spring suggestion. I could do that at the end I’m using to lower the antenna for maintenance. I’ll head over to Home Depot today and see if I can find a suitable spring.

I’m mostly concerned about ice on the ropes and wires. The trees I’m using are big. I watched yesterday during the high winds, and it looked like they were only swaying maybe 4-5 inches where my messenger rope is attached.

 

[Nashua Area Radio Society]

For maximum wind resistance, it is necessary to keep the tension in the antenna wire relatively low so that when the wind blows in a way that increases tension, the breaking strength of the antenna wire is not exceeded. This usually accomplished by allowing some sag in the antenna wire. However, this sag may also degrade antenna performance. Google “antenna sag” for more info. Like everything else, choices involve tradeoffs!

 

Rick

K8EZB

[Nashua Area Radio Society]

In case anyone else is looking for a suitable spring, the one I found at Home Depot seems just about right. It’s 1-1/8″ x 16″ and has a working load limit of 31 lbs. Made by Everbilt. HD Store SKU #170733.

I installed it using a pulley as Paul suggested above.

 

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