I wonder what the basis was for the advice you got, Jim. I have used a
Rohn 25 pointy-top with a 10-foot Rohn galvanized mild-steel mast
carrying a tribander and a shorty 40 for 15 years. At 1 RPM max, it
looks like it's good for another 15, which will be plenty, I suspect.
Depending on your rotator, a thrust bearing may be totally unnecessary
(depending on the dead-weight of the mast and antennas) or even
detrimental. I recall a discussion in Towertalk's early days of a
common rotator - maybe an Orion - whose specs actually required a
minimum vertical load,
73, Pete N4ZR
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On 3/17/2012 1:59 AM, Jim Brown wrote:
> On 3/16/2012 7:52 PM, Joe Barnes wrote:
>> I don’t see much info out there about this tower
> That's not the official name of it, but it is what it is commonly
> called. It s really an OEM part made for Motorola, and I think it's
> been discontinued for years. I was lucky enough to find four straight
> sections and a pointy-top, and it's currently holding up mono-banders
> for 20M and 15M. I had a friend make a rotor plate to fit it.
>
> For those who don't know, "Rohn 35" is heavier gauge and has wider
> spaced legs than Rohn 25, but less than Rohn 45, so it's pretty robust.
> I suspect you can find the "real" nomenclature for it by Googling Rohn
> 35 and Motorola.
>
> I have been told that pointy-top sections should not be used in place of
> thrust bearings, so you might want to consider buying a real thrust
> bearing and using that if you can't find a pointy-top.
>
> 73, Jim K9YC
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