Re Re: Di-Rectional.....

[Dan.Strassberg]

Although the Tampa 620's current pattern is very similar to the
original 1930s version (still protects WTMJ and only WTMJ--except for
incidental protections to stations built after the '30s--that is, just
about all of them) and the tower spacing and electrical parameters are
probably quite similar, the current 620 site on the west side of Tampa
Bay is NOT the 1930s site. This site was built in--I think--the '50s
(maybe even the '60s) and was extensively rebuilt in the last year or
two. The towers had to be shortened and strengthered to comply with
new hurricane-safety requirements and to rectify the ravages of
salt-air corrosion over many decades. Zoning restrictions precluded
replacing the towers; they had to be shortened and repaired, which
surely must have cost a lot more than a complete replacement would
have. A slight power increase compensates for the loss of efficiency
caused by the height reduction. In addition, although it remains
licensed for approximately 5 kW, 620 has been running a nominal 10 kW
(now a bit more) under STA for several decades to compensate for
coverage lost to Cuban jamming. There have been many postings about
the original site on Barry Mishkind's Broadcast Engineering mailing
list. Somewhere in Barry's archives, you will find the location of the
original site. My understanding is that it is both south and east of
the current site. I believe that all that remains--hidden in the marsh
grass--are the crumbling footings of the original towers.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "Robert F. Sutherland" <madprof@ix.netcom.com>
To: <boston-radio-interest@rolinin.bostonradio.org>
Sent: Saturday, September 01, 2007 3:26 PM
Subject: Re Re: Di-Rectional.....


> Kevin Vahey & Dan Strassberg  -  you rate an extreme appreciation
> award,
> and a "you rock, man!"
> for pointing to WFLA / WSUN as  1st (WSUN says so!) directional
> site.
> I've seen the Gandy Causeway towers, and never thought to check the
> history.
>
> I'd never thought to wonder where was 1st direx site,
> Thanks  to Don A   for the spark!
>
> yes, Google search shows much....(woo! thrill!)
> Including Barry Mishkind's  listing "Radio Roots Discovered at Tampa
> Bay"
> which has a color pix at the Gandy Causeway!!!  (not as clear as
> Scott's
> pix are tho)
>
> Don -  you are ever so correct, re computing power having
> eased creating a direction array plan.
> I recall a pre 1950 Engineering book, found at
> Worcester Poly Institute, which had an article & photos of a
> oscilloscope
> with input circuitry to simulate array pattern, with controls (pots)
> to provide tower / array parameters.  Today, ridiculously
> inaccurate,
> years back, saved much manual pre-calculation time
>
> Bob Sutherlan
>