On 11/17/2010 4:46 PM, Mark Robinson wrote:
> There are bushings available to go inside the Rohn top section
Not really needed unless the mast is notably smaller than the sleeve.
I might go as far as wrapping the mast that will be inside the sleeve
with PVC sheet to serve as a bearing/protection for the mast. A real
bearing isn't needed.
73
Roger (K8RI)
> http://www.3starinc.com/rohn_25ag_45ag_section_tower_bushing_r-tb50.html
>
> http://www.3starinc.com/rohn_25ag_45ag_section_tower_bushing_r-tb75.html
>
>
> Mark N1UK
>
>
>
>
>
>
> ----- Original Message -----
> From: "J.Gordon Beattie, Jr., W2TTT"<w2ttt@att.net>
> To: "'Alex Malyava'"<alex.k2bb@gmail.com>; "'towertalk'"
> <towertalk@contesting.com>
> Sent: Wednesday, 17 November, 2010 4:19 PM
> Subject: Re: [TowerTalk] question on thrust bearing
>
>
>> Alex,
>> Naw...it will be fine if your mast is going through the top section
>> sleeve.
>>
>>
>> Thanks& 73,
>> Gordon Beattie, W2TTT
>> 201.314.6964
>>
>>
>> -----Original Message-----
>> From: towertalk-bounces@contesting.com
>> [mailto:towertalk-bounces@contesting.com] On Behalf Of Alex Malyava
>> Sent: Wednesday, November 17, 2010 8:13 PM
>> To: towertalk
>> Subject: Re: [TowerTalk] question on thrust bearing
>>
>> Reviving this, 3 years old, subject...
>>
>> I am about to install 30' of Rohn 25 tower with MQ-26 (5 HF Bands 2
>> element)
>> on it rotated by Yaesu G-450.
>> I understand that antenna itself is pretty light and it will never become
>> anything bigger than MA5B, so it is an easy job for the rotator..
>> The top section of tower is "Rohn 25 top section"... I am planning to use
>> 4'
>> long "military surplus aluminum green mast" for an antenna mast.
>>
>> How exactly I skip thrust bearing step? Do I just feed antenna mast
>> through
>> that top pipe and that's it?
>> Wouldn't it be scratching and squeaking up there?
>>
>> Thanks,
>> Alex K2BB
>>
>>
>>
>>
>> On Thu, Dec 20, 2007 at 12:32 AM, Dino Darling<dino@k6rix.com> wrote:
>>
>>> A thrust bearing provides two functions...
>>>
>>> 1. Vertical load support (not really the right bearing for this
>>> application for most thrust bearings).
>>> 2. Lateral support (exactly what most thrust bearings were designed to
>>> do).
>>>
>>> The simple answer to your question is NO, as the vertical load of the
>>> MA5B is minimal. The lateral support is an advantage and will
>>> protect the aluminum from long term wear.
>>>
>>> If you can afford the bearing, buy it, but its not a "concern" in
>>> THIS application.
>>>
>>> "This is just MY opinion, I could be wrong."
>>>
>>> Dino
>>>
>>> At 07:08 PM 12/19/2007, Mikemedic130@aol.com wrote:
>>>
>>>> I will be looking to add a cushcraft m5ab mini beam (35lbs, and 3.35sq
>>>> windload) along with a
>>>> yaesu g-450a rotor to my 7-40 universal aluminum tower. Question is
>>> should I
>>>> be concerned
>>>> with using a thrust bearing? I wont be looking to add anything more
>> later
>>>> since I have a small
>>>> city lot and want to be nice to my neighbors. I currently only have a
>>> 2meter
>>>> vertical on the tower now.
>>>> I guess I am asking do I really need a thrust bearing or not? Any and
>> all
>>>> replies would be appreciated.
>>>>
>>>>
>>>>
>>>>
>>>> Thanks mike kc8unr
>>>>
>>>>
>>>>
>>>> **************************************See AOL's top rated recipes
>>>> (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004)
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>>>
>>> Dino - K6RIX
>>> dino@k6rix.com
>>>
>>>
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