Many years ago I used a car windscreen wiper motor and gearbox to do
just this. IRRC the boom was monted in two ball races and there was an
operating arm , set at 45 degrees to the main polarisation, which was
attached to the wiper motor and the boom. Sorry but I really can't
remember any further details but ISTR that I had to make the motor
operate in "one wipe" mode by frigging the switch.
hth and seasons wotzits, Mike W, G8NXD
--
On Tue, 23 Dec 2003 10:24:12 -0000, "Richard"
wrote:

Hi. Has anyone designed a way to mechanically rotate their VHF/UHF yagi so
that it can be either horizontally or vertically polarized? If so, can you
please direct me to a website or whatever. Preference right now for a
manual system, but would also take a look at motorised systems.

TIA.

Rich.

(Followup set to rec.radio.amateur.antenna, so all replies will go to this
group).

Mike W wrote:
Many years ago I used a car windscreen wiper motor and gearbox to do
just this. IRRC the boom was monted in two ball races and there was an
operating arm , set at 45 degrees to the main polarisation, which was
attached to the wiper motor and the boom. Sorry but I really can't
remember any further details but ISTR that I had to make the motor
operate in "one wipe" mode by frigging the switch.
hth and seasons wotzits, Mike W, G8NXD

Yep, that's an idea.

I could buy 2 yagis, it's not really the expense, but a question of loading
on my scaffolding pole mast! :c)

Or I figure a peice of string and some kind of mechanism.

Richard,
I remember seeing something like your string idea. Used a
'barn-door' hinge with a rope-loop attached. Pull one rope the
antenna 'stood up', pull the other it laid down. Ran the ropes
through a couple of 'turning blocks', into the shack's window.
The 'turning blocks were low on the tower so the rope sort of
twisted around the tower when the beam was turned. Didn't seem
to be much of a bother...
'Doc