Re: Plastic Antenna Insulators

Dave Heil wrote:
Mike Coslo wrote:
Dave Heil wrote:
Highland Ham wrote:
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To be UV resistant the plastic should be black ,eg it contains carbon black ( like soot) If ,in general, plastic material is exposed to sun light it deteriorates over time (especially when pigments are involved).
Example: coloured polypropylene rope .
If that material would be black ,it would have a very long life.
But then the sales of this material would decline ;)), hence you only find coloured polypropylene rope ,blue ,orange ,red , yellow ,etc ,at least in the UK.

Here in the north of Scotland (no sun in abundance) I use (blue)polypropylene guys on a 13m (40ft)mast ,which have to be replaced every 7 -8 years .But it is cheap.


I question that 7-8 year figure. Some Finnish friends put up a "temporary" tower with a tribander at the OH0Z site in the 1990s. They used new polypropylene ski rope. I went out one weekend and there lay the tower and tribander, victims of a guy rope failure. I'd NEVER use the stuff for guying or antenna supports.


I've not found the polyester stuff to be very good either. I wonder if that stuff lasting for 7 years might be something else?

Polyester or polypropylene? The polyester is pretty good even without the black UV resistant layer. Polypropylene frizzes, fades and gets weak very, very quickly.

Polyester rope as used on sailing boats is UV resistant (even without carbon black) and would last 30+ years ,but it is relatively expensive.


Polyester is excellent material. There is a polyester rope sold under the "Synthetic Textiles" name here in the U.S. which is simply great.
It is braided, not twisted. The inner core is white. There is an outer braid which is black. I have some which is fourteen years old. It is still strong and flexible.

I've seen it. I might just pt my next antenna up with it.


Does it have much stretch? I'm looking for something new after replacing my dipole the third time since January.....

One of the very good things about polyester rope is that it doesn't stretch much at all--let's say, compared to nylon rope which stretches a great deal.

Where I am at, we get some pretty strong and gusty winds the past few years. The trees can get whipping in different directions fairly often. My old nylon string would stretch, and could even
support my weight (don't ask how I know that) My thoughts are that iff I put up something that doesn't have a little give, the stress is just going to transfer from the line to the antenna. At that point I'd start breaking the antenna.

Where is your rope breaking and what is it attached to? I use plain old nylon 1/4" rope to support the end of my inverted L for 160m. The far end runs though a nylon pulley attached to another rope up in a maple tree. The rope attached to the antenna runs down the tree and is attached to an old window sash weight. The weight is free to bob up and down with the swaying of the tree. That keeps the rope and antenna wire from breaking.

Nothing so complex. I have some line running through a grook in the limbs. The failure point for the old stuff I was using was at the rub point. Now it seems almost random. Your method would probably be a lot better for me to use.


Plastic antenna insulators (sold in the UK ) are usually black , so are the outdoor balun enclosures and plastic insulators on Yagi antennes.


We're now seeing some white plastic insulators here. I tried some in the sun of Africa. They looked like they were pitted and deteriorating after three years in the sun of Botswana. I either use ceramics or make my own out of 1/2" thick clear plexiglass *** or 3/4" plexi rod. That yellows but doesn't otherwise seem to deteriorate.


I've been using black plastic eggs sold for electric fencing apps. They've worked well for about 5 years now.

They're likely a little short for high power, Mike. You might consider using a couple of them at each end with a short piece of nylon rope in between them. I use the black plastic "nail-on" fence insulators for running a beverage antenna down a tree line. They are cheap and they work well. The have a snap-in retainer so they're easy to re-use if the aluminum fence wire I'm using should ever break.

I use those Hy-Gain center insulators made of black plastic with rubber membrane and stainless screws and nuts. They never seem to fail and certainly keep water out of the coaxial cable. Ten-Tec is making their little Acro-Bat center insulator. It is good for 300 ohm window line and RG-58 but they don't make a model for RG-213-sized cable.

Once again, sounds like a setup I might want to emulate.

Thanks, Dave.

- 73 de Mike KB3EIA -
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