The shorter ones as I understand it are so you can leave them behind in the
ground without leaving your tower behind if you move and
so when you calculate height you don't loose 4ft in the ground.
I was just reading where the whole for 25G should be a min of
4.5ft deep (.5 for drain sand or gravel)
And 4 feet on each side
I also just noticed in the files from Rohn, that the allowable antenna area for
a 70MPH wind load (which isn't much wind considering
a storm of any size at all) for Rohn25G is
only 1.5 sqft at 40' in height and that is assuming:
round elements, little or no square plates, centered and symmetrical antennas,
and proper coax distribution of one RG-8 (or such)
on one leg of the tower and no more than one.
That is a very small antenna is it not?
My Hornet tribander is a lot bigger than that.
14' boom and a 14' reflector.
Which if I am calculating it correctly
makes for a lot more than 1.5 sqft
My question is how much does the HAMIV rotator add to wind load calculations as
far as square footage. Now just looking at that
thing out here in the shack, it must have some pretty heavy duty wind load all
of it's own.
How do the fellas but so many antennas on those towers and get by with it???
73 fer nw es gud DX,
QSL VIA: BUR, LotW, e-QSL
Bob AD5VJ
Old calls: WB5ZQU/WY5L/KH3-KE5CTY-N5IET
http://www.ad5vj.com/
Member: CTDXCC, NTCC, STXDXCC
FISTS: # 12637, SKCC# 2369
10X# 37210, FP#-1141
SMIRK#-5177, RARS #-149
> -----Original Message-----
> From: towertalk-bounces@contesting.com
> [mailto:towertalk-bounces@contesting.com] On Behalf Of merlin-7
> Sent: Thursday, June 28, 2007 8:03 PM
> To: jeremy-ca; towertalk@contesting.com
> Subject: Re: [TowerTalk] rohn qusestion
>
> No difference in wall thickness etc?
>
> Bottom sections are just shorter?
>
> Is it better off cost wise to just buy a normal section for
> the base and get the few feet extra in height?
>
> Thanks again
>
> > 5' feet and 6'8"
> >
> > Carl
> > KM1H
> >
> >
> >
> > ----- Original Message -----
> > From: "merlin-7" <merlin-7@sc.rr.com>
> > To: <towertalk@contesting.com>
> > Sent: Thursday, June 28, 2007 7:34 PM
> > Subject: [TowerTalk] rohn qusestion
> >
> >
> > > What is the difference between the short sections that
> you bury in
> > > concreate and a regular 10 foot section?
> > >
> > > Thanks
> > > _______________________________________________
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> > >
> >
> > _______________________________________________
> >
> >
> >
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> >
>
>
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