Just got back from our local Rohn distributor with my replacement 25G
tower and accessories. I had mistakenly ordered a pier pin base and while
trying to get that straightened out was made aware of the 25GSSB
Self-Supporting Base. This thing is massive. The distributor said it is a
new item and neither the nice lady in the office or Rita at R&L (who I
purchased the tower thru) could find the pricing info for it. Turns out it
is in a recent supplement. Anyhow, this base is made of about 1/2 inch thick
steel plate and does not have the hinge mechanism (which I did not need or
want anyway). The SSB is about $30 or so less expensive than the hinged base
so I jumped on it. I still took the 1/2 x 12 bolts for mounting and they
gave me some heavy gage 9/16 washers to use but the plate will take up to
5/8" bolts (hole dia = 11/16). Still thinking about going to the heavier
bolts though. I guess that in reality the primary function of the baseplate
is to keep the base of the tower on the concrete pad and support the tower.
Sooo, if everything else is ok the diameter of the bolts should be
relatively (within reason) insignificant. The alignment will certainly have
to be right on with only 1/16 clearance. The drawing on the Rohn website
does not show the size of the holes in the hinged base. Any comments?
I checked the Rohn web site for info and there is a drawing posted there.
Funny thing is, the date is 1999. Wonder if it took this long to get it into
production or if it is just new to this area of the country.
Also, I had ordered 3/16 guy wire, big grips, and 1/4 inch thimbles. Turns
out the Rohn book recommends 5/16 or 3/8 thimbles for use with big grips.
Changed those out while I was there too.
FWIW, YMMV, etc.
Mike / W8DN