Re: Topband: Antenna rope through pulleys...
I use military surplus pulleys. They have really narrow space between the pulley and the bracket. So never faced this problem. However, very nice and practical idea. Thanks for sharing. On Mon, 27 Sep, 2021, 01:26 , wrote: > > > > >If I think there might be an issue with the antenna rope jumping the > pulley and wedging itself between the pulley and the bracket that holds the > pulley, I drill a hole through both sides of the bracket and install a > cotter pin, with just enough room for the pulley to rotate. In the aviation > world, it's called a guard pin. It keeps the stainless steel flight control > cables from jumping off the pulley and jamming. (not a good thing!) > > See the following image: > https://www.flight-mechanic.com/wp-content/uploads/2017/07/2-74-768x463.jpg > >The larger the diameter the pulley, the easier it is to pully either a > wire or line through. I found the old pulleys from garage doors in the > scrap yard work VERY well! Just have to drill and install the guard pin. > Plus I lube the bearings/sleeve with marine grease before installing. > >With proper sizing of the pulley and antenna rope, there shouldn't be > any issue with the rope getting wedged. But the problem is they don't make > many large diameter pulleys for the small size antenna rope used. Hence my > use of old garage door pulleys that are made for small diameter cable and > have large diameter pulleys! > > YMMV > > 73 Kriss KA1GJU > > > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Corner insulator of Inverted L
I'm presuming that your setup is like mine . . . i.e. the exact point where the wire goes through the insulator is not tied, it varies, has to slip back and forth through the hole, depending on wind moving the tree branches, etc. Now I use 24 strand copper, PVC covered wire for my antennas. I've always found it to be the optimum strength to weight ratio for long spans. Although it never breaks on its own, the trouble is that where it goes through the hole in an insulator (and turns through 90 degrees) it rubs back and forth in the wind . . . so eventually it breaks due to the sawing action ! (typically once a year) The solution? About 4 years ago I soldered a MUCH thicker 2 foot length of PVC-covered wire - very flexible, about 40 strands, with even thicker insulation - at the point where it goes through the insulator. (very easy to suss out, as I was repairing yet another break). Although this piece of wire is much heavier, that doesn't matter as it's very short and supported by the insulator . . . and although it obviously goes back and forth through the hole when it's windy, it has NEVER broken ! 73 Roger G3YRO _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Inverted L's etc
1. Had a fabulous 95 ft Buckeye tree at the rear of my last property. After staring at it for a couple years, it got me on 160m with a 1/4 wave Inv-L (apex around 90 ft) Top Band came alive with my 100w, producing 550 Q's on the CQWW160 SSB contest. I was hooked on TB. 2. Winds. I had $5000 worth of trees planted on my current property ( 3 acres, but just one 20 ft tree.) , including four 20 ft maples. The guy asked if I wanted to guy them. I asked his opinion and he said he thought it wasnt necessary. So I didnt. Three weeks later we had a storm that dropped 4" of rain followed by 50 mph winds. My four maples now were about 15-20 degrees off normal, Still are.. 3. A 100# Bow and arrow was used for years to launch polyester string over 50-100 ft trees. At the last house, I was always very careful not to shoot the arrow in the direction of any neighbors house, no matter how far away. One day, as I released my arrow, the lead weights and string I had tied to the tail of the arrow came off, and the arrow damned near went in orbit. Lost sight of it, so I listened carefully for a thud on a neighbors roof. To my great relief, No Thud. I never even saw where it came down. But somewhere up the street, Im convinced a neighbor came across a perpendicular arrow in his yard. Or maybe it was in the adjacent golf course. Im not sure 4. Per the above, "an abundance of caution" is never too much to ask of yourself. _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inv L corner insulator
My hunch is that your problem is the wire you are using. My inv. L is strung with hard drawn 7 strand bare AWG 14 copper. Multi-strand or solid soft drawn will probably break on you eventually. 73 Rob K5UJ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inv L corner insulator
On 9/26/2021 12:05 AM, Jim Monahan wrote: On my property, I have an endless number of trees so I try to use the largest trees which will sway less to minimize stress on the installation. This correctly considers the options available to each of us afforded by the details of our own real estate, whether a sprawling forest or meadow, or a suburban or urban lot. I had an urban lot, now I have a sprawling forest, and I've assisted several local hams in assessing their options and fitting practical antennas into them. THAT'S what good engineering is all about! It's not about esoteric details of theoretical concepts, but rather applying fundamentals to our own individual problems and resources. What skyhooks are available, and how might we use them? Where might I locate RX antennas, and which types of RX antennas work well in those surroundings? (See W3LPL's excellent talks on this). 73, Jim K9YC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Inv L corner insulator
The pulley system is probably the best way to go as others have noted. As an option, perhaps, I use springs selected from Home Depot that are about 6 inches long. I put a loop of dacron between each end of the spring just in case of failure. They are installed at each end of the supports between two trees. The spring rate is subjective as you don't want it to stretch too easily or be to stiff. On my property, I have an endless number of trees so I try to use the largest trees which will sway less to minimize stress on the installation. And, I use fishing arrows (which have weighted tips) with a bow to shoot fishing line into the trees then 100 lb nylon line to pull up the dacron rope. This has worked quite well for over 20 years for me. Jim, K1PX _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
