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-boun...@febo.com [mailto:time-nuts-boun...@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 > > > > > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
