[Towertalk] Grounding mast to tower

[Pete Goudreau]

n4kg@juno.com wrote:

> On Tue, 2 Apr 2002 Pete Goudreau <goudpj@mac.com> writes:

>> SNIP

>> The other half of my original question was in wondering how
>> effectively capacitance of the antennae and mast is coupled to the
>> top of the tower for use in shunt loading it as a vertical.

>> Pete, AD5HD

> Very effectively. See my article on Reverse Fed Elevated GP Antennas
> in QST for JUNE 1994 or any of the subsequent ARRL Antenna Books or
> ARRL Handbooks. Of course the antenna elements need to be connected 
to
> the boom for maximum loading effect.

Been over that, very cool idea.

> When I installed an 80M inverted vee fed with ladderline spaced away
> from my 140 ft R25 tower that is also fed as an Elevated GP on 160M,
> the 160M tuning was severely impacted indicating that capacitive
> coupling of insulated conductors can still load a vertical. I merely
> tune for maximum output (my 3-500 based amplifiers don't mind the
> SWR). Performance on 160M seems to be enhanced with the 80M Inverted
> Vee providing additional loading.

Makes sense, thanks for that.  Capacitively coupling from the tower 
to the wires would be in series with their intrinsic capacitance to 
ground so the arrangement must've acted as a bit of capacitive 
loading at the top of the tower via the "vee" wires, right?

Thanks very much,
AD5HD