[TowerTalk] Fw: Rohn 45 Question

[Barry]

Another option for mast stability when the rotor is removed is 2 pieces 
of angle iron, held together with a bolt and nut, shaped like the letter 
T.  2 U-bolts hold the top of the T to the tower face and 1 U-bolt 
through the mid-section of the vertical of the T holds the mast.  Snug 
the bolts before removing the rotor, and everything stays put.

Barry W2UP

Ron Todd wrote:
> So why does a rotator want to have that second thrust bearing?
>
> I wanted two because when you take the rotor out and with only one thrust 
> bearing you don't have control of the mast horizontally. With two TB you 
> always have control.
>
>
>
> ----- Original Message ----- 
> From: "David Gilbert" <xdavid at cis-broadband.com>
> To: "jeremy-ca" <km1h at jeremy.mv.com>
> Cc: <towertalk at contesting.com>; <K7LXC at aol.com>
> Sent: Saturday, August 25, 2007 3:03 PM
> Subject: Re: [TowerTalk] Rohn 45 Question
>
>
>   
>> Carl, you pretty much avoided Steve's question.  What rotator failure
>> mode is minimized by having two thrust bearings above the rotator?   Can
>> you give any examples of your YCCC buddies that would back up your
>> comments?  It would be interesting to hear their experiences first hand.
>>
>> I recently ordered a tower, rotator, and fairly large antenna system ...
>> and both of the tower manufacturers I investigated strongly recommended
>> against using two thrust bearings (at least if both were secured to the
>> mast) for the same reasons Steve mentioned.  A single thrust bearing at
>> the top of the tower makes sense, but a simple plate inside the tower
>> with a hole in it facilitates the task of replacing the rotator (which
>> is a separate issue anyway).
>>
>> So why does a rotator want to have that second thrust bearing?
>>
>> Dave  AB7E
>>
>>
>>
>> jeremy-ca wrote:
>>     
>>> I take it then that you have never experienced the installation of a 
>>> large
>>> stacked array without a crane.
>>>
>>> Old wives tales? Hmmm, most of those that I know have at least a Masters
>>> degrees in an engineering discipline.
>>>
>>> Plus NE Yankees are not known for spending money frivolously.
>>>
>>> Cheers Yourself
>>> Carl
>>> KM1H
>>>
>>>
>>>
>>>
>>> ----- Original Message ----- 
>>> From: <K7LXC at aol.com>
>>> To: <km1h at jeremy.mv.com>; <towertalk at contesting.com>; <john at kk9a.com>
>>> Sent: Saturday, August 25, 2007 1:21 PM
>>> Subject: Re: [TowerTalk] Rohn 45 Question
>>>
>>>
>>>
>>>       
>>>> In a message dated 8/25/2007 10:00:45 A.M. Pacific Daylight Time,
>>>> km1h at jeremy.mv.com writes:
>>>>
>>>>
>>>>         
>>>>>  Thats strange. Numerous YCCC and other serious  contesters/DXers with
>>>>> big
>>>>>
>>>>>           
>>>> stacked arrays have been using dual bearings for  decades with a
>>>> significant
>>>> reduction in rotator failures.
>>>>
>>>>    Reduction because of what? Reduction from what to  what?
>>>>
>>>>    What actual mechanical improvement does the  additional mid-bearing
>>>> make?
>>>> More torque reduction? No. More vertical weight  reduction? No, the
>>>> weight's
>>>> already on the top bearing. A psychological  improvement? Probably. More
>>>> ham
>>>> radio old wive's tales? Probably.
>>>>
>>>> Cheers,
>>>> Steve     K7LXC
>>>> TOWER TECH -
>>>> Professional tower services for hams
>>>> Cell: 206-890-4188
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ************************************** Get a sneak peek of the all-new 
>>>> AOL
>>>> at
>>>> http://discover.aol.com/memed/aolcom30tour
>>>> _______________________________________________
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> TowerTalk mailing list
>>>> TowerTalk at contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>>
>>>>
>>>>         
>>> _______________________________________________
>>>
>>>
>>>
>>> _______________________________________________
>>> TowerTalk mailing list
>>> TowerTalk at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/towertalk
>>>
>>>
>>>       
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk at contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>>     
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>   

-- 

Barry Kutner, W2UP             Newtown, PA