There are bushings available to go inside the Rohn top section
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
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>> >
>> >
>> >--
>> >No virus found in this incoming message.
>> >Checked by AVG Free Edition.
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>> >12/18/2007 9:40 PM
>> >
>> >
>> >
>> >
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>> 12/18/2007
>>
>> Dino - K6RIX
>> dino@k6rix.com
>>
>>
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> 12/18/2007
>>
>>
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