[TowerTalk] Rohn 35 Tower

[Wayne Kline]

I also want to 2nd Pete ZR's experience with  Rohn pointy top 2" od tube  in RG25, RG 35 and RG45. They all having 20 plus ft  of mast material with 7= ft inserted in the tower, and shorty 40's and big Tri banders with years and years of service,  As for the rotors wanting the weight applied B-4 tightening the mast clamps Create is one who did as per there instructions.    My only problem I ever experienced was a pointy top Rohn 25G with a 14'  1/4 wall cromemolly mast driven by a W0MLY prop pitch on a 46' 4" boom HB 7 element 20 meter Beam. Where the W0MLY prop pitch can was fastened at first to the three rungs,  and in short order fatigued the welds at the Z brace. The Fix was to fab a bracket that went to the legs with 1 1/4 id u bolts  and it lasted many a year till the beam fell apart during a ice storm.  I say this with the notion that the rotors are place well inside the tower and in my experience at the joint section area.  Wayne W3EA    The fun part is to STAB a 24' mast in side a taper top at height.. BTDT to many times. 
 > Date: Sat, 17 Mar 2012 06:10:05 -0400
> From: n4zr at contesting.com
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Rohn 35 Tower
> 
> 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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