[Antennaware] Re: 40m vertical questions

[Barry L. Ornitz]

Durwydd MacTara wrote:

> .105 dia. Grass trimmer line is cheaper than dacron and just 
> as strong!

Unfortunately string trimmer line is almost always Nylon 
(Nylon 6 with plasticizers is a common composition).  Nylons 
as a class have poor ultraviolet resistance.  They are also 
attacked by acids in acid rain and in industrial environments.  
I have seen some cheap "wannabe" string trimmer 
line made from polyolefins too.  These fair even worse in 
ultraviolet exposure.

Dacron is DuPont's trademark name for their line of 
polyethylene terephthalate (PET) polyester fibers.  This 
material has excellent ultraviolet resistance.  [It dissipates 
the energy produced by ultraviolet absorption by fluorescing 
at a longer wavelength.]  PET is also resistant to most 
atmospheric pollution.

Stick with the Dacron or polyester rope if you want good life.

    73,  Dr. Barry L. Ornitz     WA4VZQ     ornitz at tricon.net