[BC] Lightning Prevention?????

[Phil Alexander]

Jerry,

The tower was too tall for a good AM signal and the top hat would make
it effectively taller yet. It might have been better to sectionalize
it and possibly drive the top section for more ground wave or run it
at ground potential strictly as a mounting support for the FM. The
best compromise is somewhere between 190 - 210 deg. If you start with
225 deg and add top loading, it is a self defeating proposition. 

A bazooka is OK, but it tends to complicate the reactance by adding 
capacitance to ground. You need to be careful so the floating impedance 
is matched as closely as possible by the isolated impedance. The 
resistances can be matched, but the reactance tends to shift a bit.
However, with the good isocouplers we have today, that is probably
a better way to go, all things considered.

On 11 May 2005 at 8:13, Robert Meuser wrote:

> Sounds to me like the tower was too tall.
> 
> R
> 
> Jerry Mathis wrote:
> > I'm not sure I understand. Are you saying the AM coverage was terrible 
> > because of the lightning top hat installation? Why would that affect the 
> > AM coverage?
> > 
> > 
> > 
> > Jerry Mathis
> > Clear Channel Radio, Tupelo & Meridian MS
> > 
> > 
> > 
> > 
> >> From: "tosenkowsky at prodigy.net" <tosenkowsky at prodigy.net>
> >>
> >> I did a job at a combo ND AM/FM in NJ. The tower was over 5/8 wave at the
> >> AM freq. It had a bazooka section for the FM and NWS transmitters. They
> >> also had installed a lightning 'top hat' 
------------------------------------------------------------------------------
Phil Alexander, CSRE 
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037




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