Just to echo Dino's opinion, maybe phrased a bit differently but with the
same intent; with the small anenna and wind load you really don't need
either vertical or lateral support. OTOH a carefully aligned thrust bearing
and rotator that would allow the mast to go through the top of the tower
without putting any bearing load on the tower top sleeve might reduce some
possible long term wear, but so would a shot of grease. Typically there is
very little wear if the mast is smooth where it goes through the sleeve at
the top of the tower.
Also as Dino said, if the cost of the bearing is not a concern go ahead and
purchase a good one. Properly installed it won't hurt.
Roger (K8RI)
>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
>>
>>
>>
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>
> Dino - K6RIX
> dino@k6rix.com
>
>
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