[TowerTalk] Stainless Steel Hose Clamps on antenna elements

[K3BU at aol.com]

Jack Schuster wrote:

> Has anyone else experienced SS hose clamps loosening?


The losening of hose clamps can be caused by the clamps and their design. If 
you use larger clamp than is appropriate (not always ideal size fits the 
diameters of tubing) then what we have is larger curvature under the helix assembly 
than what the curvature of the tubing under the clamp is (or vice versa). You 
tighten the clamp and everything seems fine and tight. But what you have in 
fact, there are some gaps between the clamp body due to mismatch between radii 
under the helix screw portion. Add tolerances in tubing, temperature cycling, 
vibration, flow of material and you end up with whole assembly "finding better 
fit" and resulting losening of the grip. Case is aggravated by thicker clamps 
that resist embracing the curvatures of tubing. Sometimes couple of smaller 
clamps can do better job.
Giving it a rest day or two and retightening helps, or trying to preform the 
clamps to fit the diameter of tubing better. Those old Hy-Gain clamps with 
screw and nut were good for electromechanical joint, but devil to take appart. 
There was never problem of joint coming appart due to loose clamp.
The best solution is to use that Dayton aluminum solder rod and solder the 
junction for perfect RF and mechanical continuous joint. Use clamps where 
dissasembly is a must.


Yuri, K3BU.us