Antenna Suspension Maintenance

My main HF antenna is a Buckmaster 80-6m OCFD. Two of my friends put it up for me just after my leg was broken in 2015.

At the time none of the 3 of us knew anything about hanging antennas. That said we/they did a great job with one single mistake, which today I fortunately caught just in time, and corrected half of the problem today.

The feedpoint of the antenna is suspended by a halyard that runs through a pulley; the pulley is at the end of a line that runs over a big-ass Douglas Fir.

The ends of the dipole are supported by lines that run through pulleys attached to trees, at the end of the lines the tension on the line is maintained by a suspended weight of about 10 lbs. I replaced those lines today; they were very close to failing after 8 years out in the elements.

The polypropylene rope mistake

The mistake was that we used polypropylene rope we bought at Home Depot. It’s not that rope bought at Home Depot is bad, it’s that polypropylene rope is bad for a use where it sits out in the rain and sun all day, every day, for years on end, constantly under tension.

After 8 years outside, in the rain and snow and sun, it looked like this:

It’s so very close to failure.

So those two end lines have been replaced with black dacron line, which in my experience holds up much better over time. In particular it’s much better in the face of UV exposure.

Over the next few days I’ll replace the overhead suspension for the feedpoint as well; the ropes for that are also pretty much completely shot.

For what it’s worth the Buckmaster antenna is in great shape. I actually have another, held in reserve for when the currently active one fails, but the one that’s been out in the elements is looking really good so far. Maybe when I lower the feedpoint I’ll find some problem but it seems bombproof.

Paracord

In addition to the polypropylene rope problem, I found another problem I still need to address - there are several places where I’ve used 550 paracord to make parts of the suspension. One part is the paracord webbing I use to build useful attachment points for the PET jugs full of gravel I use for weights to maintain tension. And another part is to form a small connector between the end insulators of the antenna and the carabiner that is the end of the suspension rope, because the hole in the insulator is too small to fit any reasonable carabiner through.

All that paracord is slowly degrading - not as fast as the polypropylene rope was, but definitely worth replacing. I’m just not yet sure what I’ll replace it with. In the case of the nets for the weights I guess I’ll just replace it with something made from dacron rope.

In the case of the insulators I’ll have to come up with something else. I’m leery of using anything metal close to the end of the antenna because I worry about coupling with the antenna and causing weird effects.

Thimbles

One particular stress on the rope is clearly any place where the rope is tightly curved - knots, or where the rope looped around some connector. The smaller the radius of the curve, the worse the degradation seems to be. In all the suspensions I’ve built recently, I’ve used metal thimbles to increase the radius of the curve and to provide a better wear surface than the rope. Looking at how this suspension, built without using thimbles, I’m pretty convinced thimbles are a great idea to prevent problems from cropping up.

Morals:

Inspecting antennas is good. Inspecting antenna suspensions is good. Inspecting them on an schedule more frequent than once every 8 years seems wise. Dacron rope is way better than polypropylene rope for antenna suspensions.