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Re: [TowerTalk] Rohn Self Support Chart Says.......

To: Dave Fuller <>,
Subject: Re: [TowerTalk] Rohn Self Support Chart Says.......
From: Robin Midgett <>
Date: Fri, 12 May 2006 12:01:34 -0600
List-post: <>
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document from 1987 has been superceded.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.
>-Dave NN5K
>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:
>>>>-----Original Message-----
>>>>[] On Behalf Of Martin
>>>>& Ann Mein
>>>>Sent: Monday, May 08, 2006 8:37 PM
>>>>Subject: [TowerTalk] self-supporting rohn 25g??
>>>>Hi all,
>>>>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...
>>>>Jeff KP3FT
>>>>Spirit And Truth Christian Radio  WJIH-LP  95.9
>>Robin Midgett K4IDC
>>615-322-5836 office - rolls to pager
>>615-835-7699 pager
>>615-301-1642 home
>>TowerTalk mailing list
>Robin Midgett K4IDC
>615-322-5836 office - rolls to pager
>615-835-7699 pager
>615-301-1642 home


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