[TowerTalk] ID of A3s boom

[Bill Coleman]

On Mar 11, 2007, at 11:33 PM, george wrote:

> Anyone know the dimensions of the inside of the boom on a cushcraft  
> A3S?
>
> I am looking to install wooden dowels into the ends to prevent the  
> elements
> from turning.

I've had my A3S up at three different locations for about 13 years  
total, and never had any problem with the elements turning on the  
boom. Do you have the elements properly assembled on the boom with  
the U-bolts coming down from the top and the saddles underneath? With  
the element hanging below the boom, the antenna should naturally seek  
to hold the elements level. (I have seen many a Cushcraft antenna at  
Field Day improperly assembled with the elements upside down)

According to the manual, the boom is 1 1/2" OD. The manual doesn't  
say, but the boom is 0.058" wall, which means the next size lower, or  
1 3/8" tubing will slip inside it. So, a 1 3/8" dowel should work.

One warning about forcing a dowel into the end of tubing like this --  
you will be trapping moisture inside the boom, which will hasten the  
corrosion of the interior of the boom, especially in the area where  
the dowel contacts the tube.


Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901