[TowerTalk] Single Point Ground

[Tom Rauch]

> Thanks for the reply Tom.  I'm using 7/8" Heliax 
> (LDF5-50A).  Is it considered acceptable to direct bury 
> that coax?  I'll probably go with conduit, but direct 
> burial might be a reasonable alternative.


Any of the modern Heliax cables I have seen are closed cell 
with the dielectric bonded to the center and shield. The 
shield is also a solid "pipe", and even if it does leak the 
water has nowhere to go.

Not only that, the primary mechanism of loss after moisture 
is contamination of the braid. it insulates all the pressure 
connections from lay to lay.

I don't give a second thought to burying my "hardline" 
cables. I recently measured the loss on a 400 foot plus run 
to my 40 meter vertical and with 26-27 watts applied there 
was 25 watts at the antenna. That cable has been in the 
ground for 8 years, and prior to that laid outside with open 
ends for years. Only the first half inch had any signs of 
the conductors discoloring.

You can of course get water in a hollow center conductor, 
but after you drain it and dry it and install connectors the 
cable is fine.