Ive doubted some of the claims about fresh water swamps based only on
personal experience. At a prior QTH I had them on 2 sides and extending to a
mile or more and the 160 vertical "appeared" to play better then expected.
All that rotting vegetation had to be good for something and it rarely froze
more than a few inches in the winter.
Carl
KM1H
----- Original Message -----
From: "Guy Olinger K2AV" <olinger@bellsouth.net>
To: <herbs@vitelcom.net>
Cc: <topband@contesting.com>
Sent: Friday, September 23, 2011 5:37 PM
Subject: Re: Topband: Effect of current max not at base of vertical.
> Apologize for earlier half-done post. Spastic hit on send key.
>
> See http://www.fybush.com/sites/2005/site-051028.html for a Franklin and a
> nice article.
>
> For 1530 kHz, that's a *pair* of two vertical halfwaves in phase. 50 kW
> gives 3545.89 mV/m for broadcasting purposes. Note the relative lack of
> neighbors, and therefore lack of 24 hour miscellaneous diodic signal
> demodulation, talking window screens, permanently lit florescent bulbs,
> etc.
>
> Note that this monster is not too far from 160m. Think big and put an
> only
> slightly downsized 160 version out in the salt shallows somewhere on the
> western side of Cheasapeake Bay. Without any controversy whatsoever as to
> ground induction losses (zero) EZNEC says this would put 13.6 dbi gain
> toward Europe at 3.1 degree takeoff. Order of magnitude: three element
> yagi.
>
> Just for comparison, if I drain Chesapeake Bay and fill it with concrete
> rubble and other urban debris (can do magical things in EZNEC) I get 5.0
> dbi
> at 12.9 degrees. The full EZNEC preloaded table follows, filling
> Chesapeake
> Bay with other dirt, or turning it into a fresh water lake. These figures
> are *without* any ground field copper underneath, as it is not needed for
> a
> current sink and I have no data on what kind of field might actually be
> employed.
>
> Urban debris: 5.0 @ 12.9d (-5.0 dB from that angle takeoff over
> seawater)
> Sandy 4.8 @ 10.7d (-6.6)
> Rocky, poor 5.2 @ 10.6d (-6.2)
> Average 5.4 @ 9.0d (-6.8)
> Forest 5.7 @ 8.7d (-6.6)
> Marshy 6.1 @ 8.4d (-6.0)
> Rich pastoral 6.8 @ 8.1d (-5.8)
> Very rich 9.1 @ 7.1d (-3.8)
> Fresh water 8.4 @ 8.9d (-3.8)
> Salt water 13.6 @ 3.1d (0)
>
> One can dream. 73, Guy.
>
> On Fri, Sep 23, 2011 at 1:21 AM, Herb Schoenbohm <herbs@vitelcom.net>
> wrote:
>
>> George, Are you familiar with the Franklyn antenna design?
>> Some broadcasters swear by them and claim a 3 db increase over a 1/4
>> vertical radiator.
>>
>> Herb, KV4FZ
>>
>>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
>
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