[time-nuts] Freestanding mast

Tom Holmes tholmes at woh.rr.com
Sat Sep 4 01:02:50 UTC 2010


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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