[TZ] Elevated radials vs buried ones

[Mike McCarthy]

Rolf,

I would think some modeling might be in order. There has been some
research done on this and I seem to recall 8 wires 8-10 deg. above the
ground gets you to within a couple dB of the buried system. They need to
take off at 45 deg. angle from the base of the tower to the horizontal
runs.  Which by my calculations would be between 7 and 9M AGL. and some
90M in length.

But don't take my word for that as fact. You need to do the leg work or
have a person exceedingly familiar with NEC run the model for you.

Let me also suggest that if coverage is reduced, perform field
measurements and go to the governmental agency regulating AM's and ask for
a power increase to compensate for the loss of efficiency.

As for cutting the tree tops, that would essentially kill the trees as the
vast majority of the growth occurs at the top.  If it is possible, seek a
limited permit to clear a narrow (say 6M) path along each radial's bearing
to protect against damage to the radials from high winds blowing trees
into the radials.  Then make sure the paths are cut at least annually.

MM

On Tue, May 17, 2016 6:50 pm, Rolf Sandmeier wrote:
> Dear Braintrust
>
> An AM station, 40 kW, 910 kHZ, single tower 330 feet had half the radial
> wires stolen.
>
> To worsen the situation, vegetation including 10 to 30 ft slim trees have