[TowerTalk] Mosley S-402

[Jim Thomson]

Date: Tue, 28 Mar 2017 05:54:13 -0500
From: Stan Stockton <wa5rtg at gmail.com>
To: Tom Martin <tmartin at chartermi.net>
Cc: TowerTalk at contesting.com
Subject: Re: [TowerTalk] Mosley S-402

I would use about 4 Stauff clamps on either side of the center of the element on an aluminum plate that was about 5" X 24" X 3/8".

73... Stan, K5GO

##  4 inch wide channel aluminum works superb, extremely strong.  You can also get channel in 3 inch and also 5 inch wide..and even wider. 
Beware,  I have 3 x different versions of 4 inch wide channel.   1st version is .187 thick across the 4 inch wide portion, with 2 inch high x .25 inch
thick, vert walls. 

##  2nd version is .187 thick across the  4 inch wide portion, but vert walls are only 1.625 tall..and  .265 thick.

## 3rd version is  .25 thick across the 4 inch portion,  but vert walls are 2 inch tall...and  .281 thick.  This is the version that I used to modify my F12-340N.
The oem F12   setup used a 4 x 8 inch  wrap around  bracket, that is bolted to the boom, with 4  X  .25 x 20 SS bolts + nylocks.  A  4 x 12 x .25  thick al plate
was bolted to the above 4 x 8 boom bracket.   On all 3 of mine, the 4 x 12 plate had a slight bend in the middle, right below the boom.   The way F12 built it,
the 4 x 12 plate doesnt quite touch the underside of the boom. 

##  My 4 inch channel is  16 inch long..which is  now bolted to the oem 4 x 8 boom bracket, so that entire mess ends up   .4375 thick, same as b4.   Except this
doesnt budge, it cant... not with any amount of vert side walls.  That leaves me with exactly 4 inchs of channel sticking out past each end of the oem f12 4 x 8 boom
bracket.  Which is ample to get 3 x  dx eng  2.5 inch saddle clamps on each end of the 16 inch long channel.  The entire assy is bomb proof.  

##  ken, W3JK of  JK antennas   uses yet a 4th version of the 4 inch wide channel.   His is  .1875 thick across the  4 inch wide portion, and his vert walls are 2 inch tall,
but the vert walls are  a hair less than .25 thick.   His stauff  clamps, made for  the 2 inch od  tubing he uses on his 40m eles, fit like a glove.  2 for each ele half.   IE:  4 
required per ele.  Then the 22 inch long channel is attached to the boom with a pair of clamping blocks. 

##  dunno how thick the boom is on the Mosely, but being a 2 el,  you could also re-enforce each end of the boom with a simple insert, like perhaps 4-6 inch long.
A 16-24 inch long channel will also re-enforce the center portion of the inner ends of each ele, but you can also do that with a short inner liner.  The various sized stauff 
clamps the dx eng and other sell, are robust, and will easily handle the mosely 40m eles.  If stauff clamps are used, make use you use the black polyimide  types, with the
backing plate. 

Jim   VE7RF