Good One Dennis,
I actually use a length [approx 10 ft long] of 2" grey PVC drainage pipe
between the rotator & the pipe from the antennas.. . and it does twist a bit
in strong winds...with a 10 element duobander 10+15m and a 10 element 2m
yagi at the top.
I don't know if that is good or not.... Does it have a cushioning effect
on the rotator with strong gusty winds????
or the opposite ??? I do have a piece of steel pipe inside the lower end
of the PVC pipe to reinforce it...
Any Comments appreciated ....
Originally, I used a section [about 2ft long] of the PVC pipe to connect two
pieces of 2" ID pipe & also be flexible enough to keep the pipe in the
rotator aligned.. and it twisted a bit in strong winds - with a 5 element
10-15m duobander yagi and an 8 element 2m Yagi at the top.
I kept checking all the bolts to see if any were loose... but never found
Lee Noonan VK2LEE
----- Original Message -----
From: "Dennis Mowers" <email@example.com>
Sent: Wednesday, September 11, 2002 8:34 PM
Subject: Re: [Towertalk] Mast Coupler
> Thanks everyone, for the many suggestions.
> I visited the BMW dealer, and had no trouble finding the part.
> When I mentioned flex disk, the parts man said "what size". He said
> they come in small, med, and large. He than walked about 5 ft, pulled
> out a couple of drawers, and brought a 4 inch disk, and a 7 inch disk
> for my inspection.
> I selected the small one. The price was $63 with tax. A little more
> than the $25 mentioned in the by Leeson.
> The actual size is 4.25 in X 1 inch thick, with 6, 1/16 inch wall
> inserts for 3/8 inch bolts. Stamped with the BMW logo, which probably
> added $30 to the price.
> A couple of weeks ago, I spent a few hours looking for off the shelf
> Most of the flexible couplers I found by searching the internet are made
> for marine applications, and expensive.
> I spent a lot of time looking at couplers in the McMaster-Carr and
> Graniger catalogs. There are several types available that might do the
> job and the ones for 2 inch shafts were also a little pricey. You need
> to buy 3 pieces. Two, 2 inch shaft couplers, and a rubber insert. As I
> recall, Boston Gear has a nice one that would be about $150 for each
> coupler, and $40 for the insert.
> So, I saved a little money, and have the joy of trying something new,
> and making my own part. The part will be a lot easier to make than the
> custom top plate and rotor shelf I just made, for the non Rohn tower I'm
> Now that I have the BMW part number, I will look for a cheaper
> substitute for the next one I need.