[UK-CONTEST] Aerial Mounting?

[Dave Sharred]

Just to contradict Chris (!!!) ; either method can be used , depending on
the type of antenna.

Chris G3VHB is a Dab hand in knowing what to do in the method that Tony I
think was alluding to.

The Force 12 Boom to mast clamp is clamped to both the mast and the boom, so
that you can assemble the side that is going into the air , with the
elements parallel to the tower.

You then upright the mast; swivel it back through 90 deg so that the
elements are correct; tighten the clamp fully, and then erect the last side
of the boom / elements from the ground (winding the tower up; insert extra
boom piece , then elements until it is completed.

At IOM (MD4K); we do in fact mount our Force 12's with the boom horizontal
to the ground. We also use Force 12's;  and we use self tappers where the
rivets should be on the ground side of the elements. You still often have to
be perched on the top rung of a step ladder though !!!

As a final thought as I am writing this (and thinking of safety !!); the
swivel method means that when winching up the antenna; in the event of a
winch rope breaking, the weight of the tower would be borne by the boom.
With a horizontal boom; this scenario would be less forgiving ! And people
would be inside the tower area !  Just a thought !

73

Dave
G3NKC

-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com]On Behalf Of Chris Tran GM3WOJ
Sent: 16 May 2008 18:03
To: Tony Bettley; uk-contest at contesting.com
Subject: Re: [UK-CONTEST] Aerial Mounting?


Hi Tony

I have two HyGain 205CAS antennas here - by far the easiest method of
installation is to mount the boom on the stub-mast, with the boom parallel
to the ground i.e. horizontal, with the boom at a convenient working height
e.g 5'.   Mount the boom to element clamps on the boom.

The upper halves of each of the 5 elements are fully assembled and mounted
on the upper side of the boom, along with the bracing wire, coax + balun -
then the tower is progressively tilted upwards, adding the lower half
elements in sections, tightening each section as you go.

Eventually the antenna is fully assembled, with the tower still tilted over
at about 45 degrees.

Don't waste time/money on any sort of swivelling clamp system - the above
method is well proven with all yagi antennas where the elements can be
broken down into short sections - rivetted antennas like Force12 are another
matter.

73
Chris
GM3WOJ

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