I've done mine that way and it's been fine for the
last 28 years! I have two RG8-type feedlines taped
together with the lower antenna being two feet above
the tower top plate.
73, Stew...
--- "Jerry Keller (K3BZ)" <k3bz@arrl.net> wrote:
> I've always used a feedline "loop" that hangs out
> and down from the tower
> leg that's half-way on the rotation circle, is
> attached to the boom a few
> feet out from the mast, and is long enough that it
> doesn't impede antenna
> rotation in either direction. I recently saw an
> installation with the
> antenna mounted about 2 feet up the mast from the
> tower top, with the
> feedline coiled about 2 turns loosely around the
> mast rather than hanging
> down. The antenna end of the coax was attached at
> the bottom of the
> mast-to-boom plate. The arrangement looked like
> those coils of cable that
> the TV trucks deploy when they raise their microwave
> towers, but only a
> couple of turns to the coil. When rotated in one
> direction the coil got
> tighter to the mast, but not touching it. In the
> other direction the coil
> got looser.
>
> My question is.... is this a good idea? I have
> never seen it before, so
> maybe it isn't in widespread use, which makes me
> wonder why not.... as it
> "appears" that it would put less stress on the coax
> than the usual U-shaped
> arrangement.
>
> Any comments or experiences about this?
>
> 73, Jerry K3BZ
>
> ----- Original Message -----
> From: "John Elsik" <wa5zup@msn.com>
> To: <towertalk@contesting.com>
> Sent: Monday, July 23, 2007 11:58 AM
> Subject: Re: [TowerTalk] Antenna/mast height above
> tower?
>
>
> > Since most tower manufacturers spec so many sq ft,
> 1' above the top of the
> > tower. Then mounting the antenna 1' above the top
> would seem reasonable.
> > The main thing is to have enough room for the
> cable loop, so it does not
> > snag on anything.
> >
> > John
> > wa5zup
> >
> >
> >
> >> From: km1h@jeremy.mv.com> To:
> rusty_atkins@yahoo.com;
> >> towertalk@contesting.com> Date: Mon, 23 Jul 2007
> 11:08:41 -0400> Subject:
> >> Re: [TowerTalk] Antenna/mast height above tower?>
> > 1 inch. As long as no
> >> part of the antenna or mount scrapes the tower
> you are > OK.> > Carl>
> >> KM1H> > > ----- Original Message ----- > From: "R
> Atkins"
> >> <rusty_atkins@yahoo.com>> To:
> <towertalk@contesting.com>> Sent: Monday,
> >> July 23, 2007 10:08 AM> Subject: [TowerTalk]
> Antenna/mast height above
> >> tower?> > > >I haven't seen many recommendations
> on this. I've googled
> >> and searched > >eham.net to no avail.> >> > What
> is the minimum height
> >> above the tower top shelf recommended for an HF >
> > beam (KT34A, FWIW).
> >> I'm trying to run as short of a mast as possible
> > > without impacting
> >> performance of the antenna.> >> > Thanks!> >
> Rusty> > K0FE> >> >> >> >> >
> >> > >
> >>
>
____________________________________________________________________________________>
>
> >> > Luggage? GPS? Comic books?> > Check out
> fitting gifts for grads
> > at Yahoo! Search> >
> >
>
http://search.yahoo.com/search?fr=oni_on_mail&p=graduation+gifts&cs=bz>
> >
> > _______________________________________________>
> >> >> >> >
> > _______________________________________________> >
> 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
>
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|