[TowerTalk] rotor-to-beam shock obsorber problem/solution

[Roger (K8RI)]

Al Williams wrote:
> ----- Original Message ----- 
> From: "Bert Almemo" <balmemo at sympatico.ca>
> Sent: Sunday, October 26, 2008 2:25 PM
>   
>> Dave Leeson, W6NL designed a great solution to the rotor-to- Beam shock
>> absorber problem, using a rubber BMW steering shaft  coupler....But that, 
>> as
>> you say, was a different cart of apples than the Killer spring-guy wire
>> idea.
>>
>> I have Leeson's Masterpiece, "Physical Design of Yagi Antennas" (covering 
>> a
>> lot on towers, also) in storage, somwhwere, and miss thumbing through it
>> once in a while.  A real gem.  It should be a reference in the Bookshelf 
>> of
>> any Tower owner/user.
>>
>> Manufacturers ought to  incorporate mention of same, so that Leeson's 
>> great
>> idea can  meet the high standards of Steve's prime directive.
>>
>>     
> Thanks for reminding us where to find this information.  It is on page 7-29.
> While watching my Steppir Monstr whip around even in moderate winds I
> suspect that it isn't the wind velocity but rather the sudden shock that 
> causes
> the boom to slip on the mast.  I will appreciate additional information from
> anyone who has used one.
>
>   
Just a word of caution.  Depending on the size, weight, and elasticity 
of the antenna plus torsional effects of the mast, it  is possible to 
hit a resonant point with any specific dampening coupling. This is 
particularly important with antennas that have long and more flexible 
elements and the more massive systems. The odds are the automotive 
coupling would have a relatively high self resonant frequency, but who 
knows when coupled into a system. 
> I am also considering purchasing a folding boom-to-mast plate and would
> appreciate information on who makes them and how they work on crankup
> towers--I understand that somehow they automatically move to a level
> position when the tower is tilted up.
>
>   
Those I've never tired.

73 and good luck,

Roger (K8RI)
> Thanks
> k7puc 
>