Meant to post the message below to the reflector. Sorry Keith.
----- Original Message -----
From: "W3YY" <w3yy@cox.net>
To: <keith@dutson.net>
Sent: Thursday, September 30, 2004 12:49 AM
Subject: Re: [TowerTalk] 80m Newbie...Help w/ Inverted V Please
> I'd be worried about the 124' (exactly one-wavelength) no-insulator guy
> wires at about the same height as the the inverted vee. If there is
> coupling, moving the antenna up a bit or in a different position relative
to
> the guy wires should reveal this.
>
>
>
> ----- Original Message -----
> From: "Keith Dutson" <kjdutson@earthlink.net>
> To: "TowerTalk" <towertalk@contesting.com>
> Sent: Wednesday, September 29, 2004 8:51 PM
> Subject: RE: [TowerTalk] 80m Newbie...Help w/ Inverted V Please
>
>
> > I have the Alpha-Delta 80 meter dipole as inverted V on my 150 foot Rohn
> 45
> > tower. It is suspended from 90 feet, and hangs off a short piece (about
4
> > or five feet) of 1 inch PVC tie wrapped/taped through the tower
(sticking
> > out about 2 feet). The legs are tied off at about 200 feet from base of
> > tower. It is direct fed with LMR400 coax. VSWR is close to 1:1. This
> > antenna was installed several years back when guys were 1/4 EHS. All
have
> > been replaced with Phillystran, but this change did not affect VSWR to
any
> > extent. VSWR measurements were made with MFJ259, and later with MFJ269
> that
> > replaced it when it went south.
> >
> > I am wondering if your aluminum stand off is causing the problem.
> >
> > Keith NM5G
> >
> >
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com] On Behalf Of Robin Midgett
> > Sent: Wednesday, September 29, 2004 3:14 PM
> > To: towertalk@contesting.com
> > Subject: [TowerTalk] 80m Newbie...Help w/ Inverted V Please
> >
> > Hi,
> > My attempts to make an inverted V resonate on 80m are not meeting with
> great
> > success. I've put up inverted V antennas before (10m & 40m) and they
> worked
> > very well...not so in this case; 2.8:1 (feed point fully up) is the best
> > match I've seen yet. I'm hoping some of you more experienced will have
> some
> > constructive input.
> > Here's the configuration:
> > 130' of Rohn 45G, on fairly flat, level ground with a 24" (out from the
> > tower) aluminum stand off bracket at the 60' level. A rope and pulley
rig
> is
> > used at the end of the stand off to haul the feed point of the V up to
the
> > 60' level. Each leg of the V is ~62' long, and there is ~ 80-90 degrees
> > between them. The ends of the wire (14 ga. stranded) are formed into a
> loop,
> > which is where a small piece of rope attaches and anchors to a stake in
> the
> > ground. Pretty typical stuff, from all I've seen before.
> > The tower is guyed at 30' intervals to posts 85' from the tower base, so
> guy
> > wire lengths (all 1/4" EHS) are 90', 104', 124' & 127', no insulators on
> any
> > of them.
> > With the feed point pulled up all the way, ~3:1 is the best match I get.
> If
> > I lower the feed point to ~50', and the ends of the wires are drooped
onto
> > the lawn, the match improves to ~1.8-2:1.
> > I'm using a MFJ-269 to make the measurements. I find really good matches
> > (~1.5:1 or better) at 12 MHz, and odd multiples up the bands.
> > I've changed the coax, no help. Removed the coiled coax choke; no help.
> > Checked continuity from shield to end of one wire, OK; from center pin
to
> > end of the other wire, OK; no shorts, either.
> > Is this possibly a case of guy wire coupling/interaction? Might raising
> the
> > feed point to a higher level help the match? Should I extend the
distance
> > from the side of the tower to the feed point?
> > Thanks,
> > Lost in H.F....going back to VHF+....Robin KB4IDC
> >
> > "Success is the ability to go from failure to failure with no loss of
> > enthusiasm." -Winston Churchill
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> any
> > questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
We
> ather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
> questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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