Hmm...that's interesting, thanks for the file.
Given that Steve has maintained that 25G isn't self-supporting at any
height literally dozens of times on this reflector, I wonder if that
document from 1987 has been superceded.
I know that the tower is now manufactured by others (not Rohn); is
that the reason you refer to it as RH-25, as opposed to the long
tradition of 25G?
I agree..temporary guys are necessary at least for antenna & feed
line & tower installation purposes. The risk beyond that lies
entirely with the owner. Additionally, if this tower were erected and
not guyed, anti-climb panels should be installed without question.
Without the panels & guys, if some unwary person were to climb this
tower, he/she & the owner would be at terrific risk.
At 09:17 AM 5/12/2006, you wrote:
>I have the Rohn Chart that shows RH-25 can self support 1.5 sq.ft of
>windload at 70 MPH with no ice.
>For 90 MPH is self supports 1.7 sq. ft 30 feet of height (no
>ICE). The specs are for 3 - 5/8 feedlines and round antenna members.
>If I were doing this and had to climb it, I would install temporary
>rope guys and climb in no wind conditions.
>20 ft of RH-25 will self support 6.9 sq feet of antenna at 90
>mph. I am really comfortable putting up RH-25 sections with a Gin
>pole 2 or 3 sections above the temporary guys but not more... so
>this fits what I feel is safe when I am on the tower.
>Robin Midgett wrote:
>>Yes, I can tell you...No, absolutely not! 25G isn't self-supporting
>>at any height. Additionally, if you were to erect this 40' tower
>>without guying it, someone would have to climb it and install the
>>antenna...making for a very dangerous situation. The ice loading
>>situation that someone else mentioned is another reason not to do this.
>>Granted, hams have used this technique and gotten away with it for
>>years...but that doesn't justify doing it. You should either guy
>>the 25G installation or use self-supporting tower.
>>At 05:32 AM 5/10/2006, you wrote:
>>>>[mailto:email@example.com] On Behalf Of Martin
>>>>& Ann Mein
>>>>Sent: Monday, May 08, 2006 8:37 PM
>>>>Subject: [TowerTalk] self-supporting rohn 25g??
>>>>Can anyone tell me if it's OK to install a 40' tower, made from
>>>>four 10-foot sections of Rohn 25G, as a self-suppoting
>>> tower? The antenna that wpould be on the tower is a small
>>> omni-directional circularly-polarized FM antenna for 95.9 MHZ, so
>>> it is small with not much windload. How big does the cement base
>>> have to be? Locally, the minimum concrete order is 4 yards. We
>>> are located in upstate NY. 4 yards would be somewhere around a
>>> 4.5' X 4.5' X 5.5' foot base.
>>>>Thanks and 73...
>>>>Spirit And Truth Christian Radio WJIH-LP 95.9
>>Robin Midgett K4IDC
>>615-322-5836 office - rolls to pager
>>TowerTalk mailing list
>Robin Midgett K4IDC
>615-322-5836 office - rolls to pager
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