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#31
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From Rain City (Seattle). *I did this in a Maple forest. *I did mine
with pulleys top and bottom with a continuous loop like a flag pole. I snip Instead of pulleys, I use large screw-in insulators like you might see on a power pole. They are slick enough to act as pulleys, large enough to take two ropes (one for the continuous loop and the other for holding the antenna), they don't cost much, and a rope NEVER jumps out of the "pulley"! I've also used a screen-door spring (or two in parallel) between the rope and the end-of-the-antenna insulator (with some more rope in between so the spring doesn't add much capacitance to the antenna proper) to give some strain relief. --Myron A. Calhoun, W0PBV. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge. |
#32
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Myron A. Calhoun wrote:
From Rain City (Seattle). I did this in a Maple forest. I did mine with pulleys top and bottom with a continuous loop like a flag pole. I snip Instead of pulleys, I use large screw-in insulators like you might see on a power pole. They are slick enough to act as pulleys, large enough to take two ropes (one for the continuous loop and the other for holding the antenna), they don't cost much, and a rope NEVER jumps out of the "pulley"! I've also used a screen-door spring (or two in parallel) between the rope and the end-of-the-antenna insulator (with some more rope in between so the spring doesn't add much capacitance to the antenna proper) to give some strain relief. --Myron A. Calhoun, W0PBV. Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge. Myron; The only problem with your insulators is that the tree is alive and still growing. It will eventually grow around the insulator and embed it in the wood. This will take a long time but they are still finding cannon balls in trees left over from the Civil War. Dave WD9BDZ |
#33
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![]() "Roy Lewallen" wrote in message ... Buck wrote: I can't speak for your specific situation, but here is how I handled the similar situation. I used either a multi-band-parallel dipole (sometimes referred to as a fan dipole) or a 135 foot dipole fed with 300 ohm twin-lead. These antennas were raised about 100 feet or so into trees by mason's line which can be purchased at Walmart or most hardware or building supply stores. . . . While I still use it today, I don't recommend it for anyone wanting to put up a permanent antenna and just leave it alone for more than a year. I don't think it works equally well for all kinds of trees. For many years I've used nylon twine or mason's line for raising Field Day antennas. The trees here in the Pacific Northwest are of course mostly evergreens which have a lot of pitchy sap and in many varieties, fairly soft wood. An antenna with a fair amount of tension causes the line to dig into the wood in a very short period of time. And even after two days, the line can sometimes be hard to get down because of being seized in the pitchy slot it cuts in the wood. So while it's fine for a very short time temporary setup, I don't consider it viable for longer term installation in the kinds of trees we have here. Roy Lewallen, W7EL If it is going to be a either temporary or permanent you might want to use the first line up to hold a pulley, then run the antenna line thru the pulley. Another way is to run your line thru a couple thickness of plastic tubing positioning the tubing over the branch to keep the line from digging into the bark. Also, if you have a old spare bowling ball (don't laugh), either the 4lb (duckpin) or the 16lb (tenpin) they make great weights for the end of the lines instead of having to use a pail with cement for the weight with eyebolt. Most of the bowling balls are made from hard rubber - all you do is drill a hole and insert some epoxy glue or super glue in it and then screw-in an eyebolt type of screw! When the wind blows and the tree sways the antenna line should remain constant. Make sure that the line is about 3 - 5 ft above the ground when using a weighted system. 73 de Howard W3CQH |
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