Topband: Beverage Woes

[Bill Wichers]

While I have tried this myself, you could try black UHMW for your supports on the middle posts between the ones taking tension. UHMW is Ultra High Molecular Weight polyethylene. The black stuff holds up outside pretty well. It wouldn't be hard to make a small support with a bottom and top piece and a spacer on either side so that the ladder line could slide a bit inside. The UHMW won't wear through the insulation of the wire as much as a harder material would, and it should hold up in the weather well itself.

UHMW is cheap and easy to get. There is some on Ebay now, otherwise any plastics supply house should have it. It's commonly used as a wear material industrially.

  -Bill


> I have two bidirectional 720 ft beverages that use 450 ohm ladder line,
> oriented NE-SW and NW-SE. The ladder line is supported by 4x4 wood posts,
> about 7 ft above ground, spaced every 60 ft. The antenna works well, but has
> turned out to be a maintenance nightmare. My first mistake was to anchor
> the ladder line to the top of each 4x4 post using little plastic clamps (DX
> Engineering). Those lasted about a week before being pulled apart by the
> wind. I replaced them with wood pressure plates screwed down over the
> ladder line with 2" lag screws into the top of the posts. Those lasted about a
> year before cracking and splitting. The ladder line turned out to be very
> fragile. The plastic material gets brittle and cracks, and the wind causes metal
> fatigue and eventual failure of the strands.
> 
> 
> 
> I've spent the past three afternoons patching up the beverages for the
> winter DX season and am only about half done.Yesterday, I thought I had
> everything fixed and only needed to phase the ladder line properly. I left one
> wire open and grounded the other wire at one end, and then used a DMM to
> identify the grounded wire. To my dismay I found an open circuit on both
> wires. A spent a couple of hours with a toner trying to find the break, but to
> no avail. Then, it occurred to me that my Fluke 87-V DMM may be giving me
> erroneous readings. I replaced the Fluke with my trusty Simpson 260 and
> discovered the wire was actually intact. Evidently, the Fluke's sensitive solid
> state ohmmeter circuit had been overloaded by the inductance/capacitance
> of the ladderline or possibly RF pickup. I should have known better from the
> get-go.
> 
> 
> 
> So now, I've got one of my beverages working and will start repairs on the
> 2nd one. I've decided ladder line is a terrible choice for a beverage antenna,
> at least in New Mexico, where there is intense UV sunlight and windy
> Springtimes.  My plan is to replace the ladder line with parallel strands of 12
> AWG copperweld wire, with pass-through insulators on each 4x4 post, and
> the wire anchored at each end. I'll use turnbuckles to adjust the tension. I'm
> really tired of repairing the damn antennas, and my feet hurt from hiking
> back and forth to each end.
> 
> 73,
> 
> Jim W8ZR
> 
> _________________
> Topband Reflector