Antenna Question

Most hams feel that an antenna height of 1/2 wavelength above ground is good enough; that means 10 meters for a 20-meter beam, or about 33 feet.

Of course, while your antenna can never be too high, your home insurance premiums are a different matter. Sorry to be a killjoy, but your first step here is to make sure you're not going to lose your house to a windstorm or a lawsuit.

Check (quietly, of course) if the tower was erected under a permit, and if it's properly placed so that it can't hit your neighbors' property if it falls. The "pencil" test is always a good guide: cut a piece of wood to the proportionate height of your tower (varies with the map ratio), and see if it touches your neighbor's land when you lay it down on the map.

If you have a legal tower, then check you home insurance: you'll probably need a rider to cover damage caused by a tower failure. Be sure to check if you're covered for towers that support TV antennas: that might be a loophole your insurance company didn't think of. If not, shop around: the ARRL offer some insurance options to members, and that may turn out to be the least expensive option.

After all that, get a professional evaluation of the tower's condition, including strain tests on the guy wires, and have any needed repairs done. The engineer will give you a "safe load" figure that represents the maximum amount of "wind loading" your tower can reliably withstand, so be sure to buy antennas whose loading figures add up to less than the maximum the engineer gives you.

Be prepared for sticker-shock: I have a five-band beam with no traps, that has less than 12 lbs of wind-loading. It cost about $1,200. If you decide to allocate your money somewhere else, then you can use the tower for wire antennas, and your dipoles will get a lot of benefit from the height.

If you're in an earthquake zone, all bets are off. Sorry.

William Warren

 

Thanks for the info. No worries about hitting a neighbor, too much property in between. I will check with my homeowner policy as to what it will/won't cover. All guy lines will be new and I will be using drilling rig anchors so no problem there. As far as inspection goes, I hold SCWI (Senior Certified Welding Inspector) certs through the AWS and ASME along with all the related testing equipment-Dye Pen, Mag Particle-dry and wet, as well as having my own rad source/development lab for X-Ray and ultra sound equipment. Last but not least I have 33 yrs welding/fabrication experience all over the globe.

 

Shucks, I even disconnect the computer if a storm approaches. Live on a 9 mile dead end road and lighting feed back can nail you through the land line.

 

Smaller words, Tully....

 

Sorry, after rereading it a couple times, it does sound a bit stuffed shirtish, was not my intent.

 

I just finished a 5 element Yagi-Oda Beam. Had a little trouble finding some free RG8 coax for the gamma match. I needed 12 inches and then had to find a soldering iron. Got nothing out here but the habit.