[BC] bonding AM tower sections

[Cowboy]

On Tuesday 27 June 2006 11:46 am, Rob Atkinson wrote:
> 
> Hi all,
> 
> a ham, putting up a 4 tower array for 3.5 mhz, is using sections of rohn 25 
> and is wondering if anything special has to be done to bond the sections 
> together for long term conductivity.  It seemed to me that this is an area 
> where you guys might have some useful advice.  Are AM tower sections bonded 
> in any special way (tack welding for example) or is the compression from 
> weight and standard bolting of leg flanges enough?   I'd guess the latter 
> but wanted to be sure.

 Depends on the tower.
 I've talked to Wayne directly, so I know that Magnum steel by design will have
 some 80 KIPS per flange, so welding *should* be unnecessary.
 Generally, we tack weld them anyway.

 For ham use, I would ( and have ) simply silver-braze a #10 jumper across
 each joint.

 Commercial towers will stand for decades. With ham equipment, that's
 not the case, so the #10 jumper allows you to simply cut the jumper
 when the structure is disassembled, or  modified for whatever reason.

 The whole idea, is to maintain electrical continuity throughout.
 You *could* run a wire ( #14 copper for instance ) the whole length,
 top to bottom, and for amateur purposes it would have continuity.
 I'd still hose clamp it at least once per section.

-- 
Cowboy