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@aol.com>
> To: <km1h@jeremy.mv.com>; <towertalk@contesting.com>; <john@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@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@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|