Mine lasted over 30 years!!!!!
On Sat, 15 Sep 2012 09:14:03 -0400 "Joe Subich, W4TV" <lists@subich.com>
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" <kl7ai@hotmail.com>
> > To: <towertalk@contesting.com>
> > 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!
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