There's little or no difference between 50 and 70 feet on 80M.
Bill, N3RR
----- Original Message -----
From: Brad Nowak <bnowak@telocity.com>
To: Bill Hider <n3rr@erols.com>
Sent: Thursday, April 26, 2001 12:32 PM
Subject: Re: [TowerTalk] Guy wires as inverted Vee?
> I agree with Bill. I tried a steerable 80M inverted Vee using the tower
as
> the "ground" side and the results weren't very good. While there was some
> difference in the directivity, it was at best about 3dB. 95% of the time
> there was virtually no difference in received sigs. In all fairness
though
> my apex was only at 50'.
>
> Brad - N8SNM
>
> ----- Original Message -----
> From: "Bill Hider" <n3rr@erols.com>
> To: "Tom Mattus" <wa9wsj@yahoo.com>; <towertalk@contesting.com>
> Sent: Thursday, April 26, 2001 02:15 AM
> Subject: Re: [TowerTalk] Guy wires as inverted Vee?
>
>
> > Tom,
> >
> > Think about what you are trying to do from an antenna propagation
> > point of view.
> >
> > As stated, you wish to obtain some kind of directivity-switching by
being
> > able to switch
> > from one set of inverted "V" wires to another set, right?
> >
> > Well, at 70 feet high, a 75/80M inverted "V" has little or no
> > directivity.
> >
> > An 80M inverted "V" at 0.5 wavelengths high (130-140 feet)
> > exhibits approx a 6 dB front to side ratio. (At 32 Deg elevation
take-off
> > angle.)
> > REF: ON4UN's Low Band Dxing Third Edition, page 8-19.
> >
> > At 0.25 wavelengths (approx 70 feet) that would drop by
> > 1 or 2 dB (ibid., fig 8-5, page 8-6), making it essentially
> omnidirectional
> > with a front-to-side of
> > 4-6 dB (or approx one S-uint).
> >
> > So, in my view, there would be no point in building a "steerable" 80M
> > inverted "V"
> > with an apex at 70 feet using guy wires or any other mechanism.
> >
> > That said, I've used inverted "V" antennas for over 30 years on 160, 80,
> 40,
> > and 20 M,
> > including 80M inverted "V"s with an apex of 52 feet. They perform
> > very well. I've worked much DX with that "low" 80M inverted "V".
> >
> > I currently use a 160M inverted "V" with an apex at 134 feet, and it
> > is a barn-burner of an antenna. Note that this antenna is a scaled
> > version of what you are contemplating - It's at 0.5 wavelengths
> > high and is quite omnidirectional. Check out the details
> > at: www.erols.com/n3rr
> >
> > So, abandon your idea of a steerable switching 80M
> > inverted "V" at 70 feet as a waste of time and energy for only
> > 4-6 dB of "steerabiltiy", but don't abandon your idea of a fixed 80M
> > inverted "V"
> > at 70 feet. It will perform excellently (albeit omnidirectionally).
> >
> > 73,
> >
> > Bill, N3RR
> >
> >
> > ----- Original Message -----
> > From: Tom Mattus <wa9wsj@yahoo.com>
> > To: <towertalk@contesting.com>
> > Sent: Thursday, April 26, 2001 2:43 AM
> > Subject: [TowerTalk] Guy wires as inverted Vee?
> >
> >
> > > Hello again! What is the collective wisdom on using
> > > guy wires as an inverted Vee? Specificaly for 75
> > > meters, maybe switchable from side to side? Since I
> > > have the opportunity to incorporate this idea, before
> > > the system is constructed, I would like to know if it
> > > is really that good. What complications might I be up
> > > against? They will be on a 70' tower. Hmmm, another
> > > thought, would it be more efficient to load the tower
> > > instead? Insulating the guys from same, etc...
> > > I haven't run across this in the archives, unless I
> > > just missed it, a guy can go stir crazy looking at all
> > > that good info!!!
> > >
> > > Thanks again,
> > > Tom
> > >
> > >
> > >
> > >
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>
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