On 4/29/2011 7:49 AM, Mike Cizek W3MC wrote:
> Hello Guy -
> You don't want a mast mount for your rotor. Use a couple pieces of
> angle coming out from a corner of the tower and mount it directly on
> them. It's best to do it a a section joint using heavier horizontal
> braces; G22, G23 G24 - and use a pair of G25s for your rotor mount.
> Put another one at the next higher section joint, and mount your
> thrust bearing there. I can send you pictures if you like. You will
> get almost 300 degrees of rotation this way.
I've used a "swing arm" arrangement made of pipe, pipe fittings, steel
tube, and saddle clamps that take the "tilt" or leverage off the
rotator and gives close to, or even more than 300 degrees of rotation.
I reamed out two "T's" for bearings. The rotator was mounted about 2
1/2 feet out with about a 2 to 3 foot arms. However this does increase
the wind load on the rotator and the tower.
The antenna was mounted on a piece of steel mast between the arms and
at a right angle to the arm. The critical part is the elements of the
antenna have to clear the tower. At the tower you'd be limited to 120
degrees for each leg, but due to the "reach" or length of the stand offs
to the rotator the arms can swing well past 120 degrees for each tower
side whether you mount the arms parallel with one side or straight out
from one leg.
If need be I could sketch this out for clarity and post it although it
might take me a while to get it posted on my page.
> If you really want a lower mast mount for the Ham IV, I have a couple
> sitting here I will gladley sell - but I don't recommend it for this.
> Mike W3MC
> On Fri, Apr 29, 2011 at 00:25, Guy Molinari<firstname.lastname@example.org> wrote:
>> Anyone have any recommendations for mounting a Ham IV atop a 2" mast
>> section. I'm building a standoff mount on one of my towers for a 3
>> element SteppIR. I've got some 2" angle iron that I'm going to bolt in
>> place of 2 sets of steps on my AB-105 tower. This will allow for about a
>> 4' piece of mast held about 10-12" from the tower.
>> Now I just need to track down a mount for the Ham IV. I should get about
>> 100 degrees or so of azimuth. Together with the 180 feature of the SteppIR
>> it should do the trick for JA/CA mults and for keeping the US off my QRG
>> when I've got the big boys pointed at EU.
>> Any thoughts?
>> Guy, N7ZG
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