[time-nuts] Freestanding mast

Tom Holmes tholmes at woh.rr.com
Tue Sep 7 16:32:14 UTC 2010


HI Bill...

Yes, the HDBX version goes that high, it was the base BX that I didn't think
went past 50 feet.

Tom Holmes, N8ZM
Tipp City, OH
EM79


> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of WB6BNQ
> Sent: Friday, September 03, 2010 9:38 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Freestanding mast
> 
> Tom,
> 
> Actually the Rohn HDBX towers went up to 64 feet (not counting any pipe
used to
> mount the Beams) free standing as I have one.  What happens is the amount
of
> allowed loading decreases with height.  Just sticking up a GPS antenna
would not
> overload a HDBX at 64 feet.
> 
> You are right about it being a PITA as for climbing.  Each section is only
8 feet
> in length but narrows as it goes up.  It is possible with the right base
to have
> it in a tilt-over arrangement.  Otherwise, it helps to rent a man-lift to
do the
> assembly if you got the guts to go in one.
> 
> Bill....WB6BNQ
> 
> 
> Tom Holmes wrote:
> 
> > Charles...
> >
> > Rohn's HDBX series would go to 50 feet, free-standing. It is a real pain
to
> > climb because the braces cross in an 'X' pattern, but is quite sturdy.
Two
> > reasonably fit climbers plus a one person ground crew could put it up in
a
> > few hours once the base is ready. These towers tend to twist more than
rock,
> > unlike Rohn 25, 45, or 55.
> >
> > For your minimal load GPS antenna, even the BX series would be adequate,
but
> > I don't believe there is a 50 foot version.
> >
> > Now that I think about it, Rohn sold off all of the various BX series,
and
> > it is now marketed by Thomas & Shelby.
> >
> > Any piece of tubing you would try to take to 50 feet would likely buckle
> > under its own weight and length pretty quickly (all of you ME's and
physics
> > majors can correct my terminology and choice of failure modes off list,
the
> > point being that it WILL fall down if you can even get it put up), and
would
> > definitely need to be guyed.
> >
> > This leads me to another possibility, if money is not a concern. One ham
> > friend of mine has a 120 foot tower that is based on those tapered
lighting
> > supports you see along the freeways. It is galvanized and consists of
three
> > sections that simply nest for about a 10 foot overlap. Of course, it
takes a
> > crane to assemble. Remember, I said if money is not a concern...but it
does
> > look very nice and serious and professional. Climbing it is not for the
> > faint of heart, believe me!
> >
> > Tom Holmes, N8ZM
> > Tipp City, OH
> > EM79
> >
> > > -----Original Message-----
> > > From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
On
> > > Behalf Of Charles P. Steinmetz
> > > Sent: Friday, September 03, 2010 1:08 AM
> > > To: Discussion of precise time and frequency measurement
> > > Subject: Re: [time-nuts] Freestanding mast
> > >
> > > Stanley wrote:
> > >
> > > >ROHN 9H50 34 Foot Telescopic TV Wireless Antenna Push Up Mast
> > >
> > > Interesting suggestion.  Rohn is well known to me, though I don't
> > > typically think of them for things like push-up masts.
> > >
> > > For those suggesting 6-10' of pipe, at my rooftop I get a reception
> > > cone of about 50 degrees elevation and above during the vegetated
> > > months (say, mid-March through mid-November), and about 30 degrees
> > > and above in the dead of winter, due mostly to dense tree cover that
> > > is 60-80 feet tall.  So, I'd really need to get 20 feet + above the
> > > chimney (50+ feet above the ground) for a significant
> > > improvement.  The suburban residential lot size doesn't leave me much
> > > to work with (no centrally-located tower, therefore no guys unless I
> > > negotiated easements with the neighbors, and Hell will never be that
> > > cold...).  I doubt I could get a permit for 80' of Rohn 55.  Maybe if
> > > I put a wind generator on it....
> > >
> > > Thanks again,
> > >
> > > Charles
> > >
> > >
> > >
> > >
> > >
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> 
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