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## Re: [TowerTalk] FW: Antenna spacing on mast

 To: lists@subich.com Re: [TowerTalk] FW: Antenna spacing on mast k2qmf@juno.com Sat, 15 Sep 2012 12:02:01 -0400 mailto:towertalk@contesting.com>
 ```Mine lasted over 30 years!!!!! On Sat, 15 Sep 2012 09:14:03 -0400 "Joe Subich, W4TV" writes: > > > running this problem through a mast calculator program shows a > wind > > survival of 93 mph with the following assumptions: > > That also assumes no ice. Add even 1/4" to 1/2" of ice and the > wind > survival drops significantly. One doesn't need to be in KL7 to > deal > with high winds and ice simultaneously. > > With multiple antennas on a mast it's not a matter of whether water > pipe will bend, it is how soon will it bend. > > 73, > > ... Joe, W4TV > > > On 9/15/2012 8:53 AM, TexasRF@aol.com wrote: > > Hi All, running this problem through a mast calculator program > shows a wind > > survival of 93 mph with the following assumptions: > > > > 1.9" OD .145" wall water pipe > > yield strength of pipe 27ksi > > pipe length 48" > > antenna load 5 sq ft > > > > Changing the antenna load to 2 sq ft increase wind survival to 143 > mph. > > > > 73, > > Gerald K5GW > > > > > > > > > > In a message dated 9/15/2012 6:32:45 A.M. Central Daylight Time, > > lknain@nc.rr.com writes: > > > > Don't forget about the moment generated by the antenna. Wind > pressure of > > 100 > > mph is about 40 psf IIRC. That means an antenna at 4 feet that > has a wind > > load of about 182 lbs would deform the pipe at the bottom of the > 4 feet > > (based on your 750 psf figure and ignoring the wind load on the > pipe > > itself). At 40 psf that works out to about 4.5 sq ft of antenna. > If the > > pipe were longer the antenna size would be less for the same > effect. > > > > 73, Larry W6NWS > > -----Original Message----- > > From: KM5VI > > Sent: Friday, September 14, 2012 5:57 PM > > To: towertalk@contesting.com > > Subject: [TowerTalk] FW: Antenna spacing on mast > > > > It would take a wind pressure of over 750 psf to bend a 4' > section of 2" > > SCH > > 40 pipe to the point of permanent deformation. 750 psf is about > 30 times > > as > > much pressure as would be generated by a 100 mph wind. > Strength-wise it > > would be no problem for a vhf antenna at this length. > Interference-wise, > > the VHF antenna is really too small to affect the HF antenna even > at close > > wavelength. At VHF, 4 ft is substantially enough wavelength away > that the > > HF antenna that it should not adversely affect the VHF > performance. > > > > KM5VI > > > > > > > > > > > > > > > > > > -----Original Message----- > > From: TowerTalk [mailto:towertalk-bounces@contesting.com] On > Behalf Of > > David > > Thompson > > Sent: Friday, September 14, 2012 2:21 PM > > To: Michael Zeglen; towertalk@contesting.com > > Subject: Re: [TowerTalk] Antenna spacing on mast > > > > Please don't use Sch 40 water pipe even for a VHF antenna. > Exposing 4 or > > more feet increases the chance of it bending in the wind. Water > pipe > > strength is a flow inside not outside wind strength. > > Dave K4JRB > > > > ----- Original Message ----- > > From: "Michael Zeglen" > > To: > > Sent: Friday, September 14, 2012 2:42 PM > > Subject: [TowerTalk] Antenna spacing on mast > > > > > >> > >> > >> > >> > >> Want to mount my 2m - 440 small beam antenna above my Pro57B. > How far > >> shouuld I space it or or does it really matter as long as there > is 3 - 4 > >> feet spacing. I realize the more the better. What do you > suggest? What is > >> good rule to follow. Sched 40 pipe is NO problem my son is a > plumber! > >> _______________________________________________ > >> > >> > >> > >> _______________________________________________ > >> TowerTalk mailing list > >> TowerTalk@contesting.com > >> http://lists.contesting.com/mailman/listinfo/towertalk > >> > > > > > > _______________________________________________ > > > > > > > > _______________________________________________ > > TowerTalk mailing list > > TowerTalk@contesting.com > > http://lists.contesting.com/mailman/listinfo/towertalk > > > > _______________________________________________ > > > > > > > > _______________________________________________ > > TowerTalk mailing list > > TowerTalk@contesting.com > > http://lists.contesting.com/mailman/listinfo/towertalk > > > > _______________________________________________ > > > > > > > > _______________________________________________ > > TowerTalk mailing list > > TowerTalk@contesting.com > > http://lists.contesting.com/mailman/listinfo/towertalk > > > > _______________________________________________ > > > > > > > > _______________________________________________ > > TowerTalk mailing list > > TowerTalk@contesting.com > > http://lists.contesting.com/mailman/listinfo/towertalk > > > _______________________________________________ > > > > _______________________________________________ > TowerTalk mailing list > TowerTalk@contesting.com > http://lists.contesting.com/mailman/listinfo/towertalk > ____________________________________________________________ Woman is 57 But Looks 27 Mom publishes simple facelift trick that angered doctors... http://thirdpartyoffers.juno.com/TGL3141/5054a68eeeaa2268e0a38st04vuc _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
 Current Thread [TowerTalk] FW: Antenna spacing on mast, KM5VI Re: [TowerTalk] FW: Antenna spacing on mast, TexasRF Re: [TowerTalk] FW: Antenna spacing on mast, Joe Subich, W4TV Re: [TowerTalk] FW: Antenna spacing on mast, k2qmf <= Re: [TowerTalk] FW: Antenna spacing on mast, Joe Subich, W4TV