[Fwd: Roof Mounted Antenna Farm]

[Bruce (AA8U)]

At 02:21 PM 6/9/96 -0700, you wrote:
>I'm resending as it does not appear to have made it the first time.
>X-Mozilla-Status: 0001
>Message-ID: <31A1CF8F.6624@ibm.net>
>Date: Tue, 21 May 1996 07:13:35 -0700
>From: Richard Thorne - WB5M <rthorne@ibm.net>
>X-Mailer: Mozilla 2.0 (Win16; U)
>MIME-Version: 1.0
>To: cq-contest@tgv.com
>Subject: Roof Mounted Antenna Farm
>Content-Type: text/plain; charset=us-ascii
>Content-Transfer-Encoding: 7bit
>
>I received permission from our Land Lord (for our office space) to
>build my station on top of the building.  Its an old JC Penny building
>and the roof is huge and is made of steel.
>
>I'm going to contact a professional engineer to design the base and
>guy anchor points, have them installed and then put the tower up myself
>, with a ground crew of course.
>
>Anybody out there have experience building on to of a two story building?
>Any advice or experience is appreciated.  I need to work through a few
>issues like grounding how high to put the antenna's ect.  The room is
>about 30' above the ground and I have 90' of 25g to put on top of
>that.  
>
>I'm hoping to have this all complete before the October contest season
>begins.
>
>Thanks

Hello Richard,
>From my experience, I would say you should have a near ideal ground plane
under all your antennas. Use building steel for your ground system and
connect to it using excellent connections, cad-weld if you can. 

You might consider using a "roof crew" rather than a "ground crew"......hi

Our company radio system uses roof mounted towers, some 90' and larger at
several district offices. They have been up for many years. They are well
guyed and grounded. Of course they only support low band vhf and high band
vhf antennas. 

Using a professional to design is wise. What ever, just do it safely or
don't do it. 

Some friends of mine in JA land have large antennas on top of university
buildings and they really get out well. One tower on each building with
large mono-band yagi antennas. The towers are only about 40-60' tall, but
the height above the average terrain where the reflections take place, make
these short towers effectively much taller. 

Don't forget to ground all the guy wires if you choose solid wires instead
of insulated sections. Building steel is usually an excellent low impedance
ground system. If you use side mount antennas, don't over stress the 25G.
Torque arms are highly recommended in either case. I always install an extra
set of guys, sometimes two extra to overbuild. Most of the Rohn spec's
assume commercial vhf antennas, I think. Again go with the advice of the
Pro's..... 

I copied this to Towertalk so you could get some more good advice. Hope you
don't mind.

Hope to hear you on in the comming contest season from your new super qth.

73,
Ugly
AA8U  ZK1AAU