Oops. I was thinking of 40M, but said 80. Nothing new, I've been groping in
the dark since 1941. I do have EZNEC 3.0, but haven't yet sorted out what
the effects of the tower proximity and the 33' boom C3XL above the dipole
are. Unfortunately I'm still a newbie where antenna modeling is concerned.
Thanks for your input.
73, Jerry
----- Original Message -----
From: "Guy Olinger, K2AV" <k2av@contesting.com>
To: "Jerry Kincade" <w5kp@swbell.net>; <towertalk@contesting.com>
Sent: Thursday, May 30, 2002 10:47 PM
Subject: Re: [Towertalk] Dipole height
> Moving the center of a 75/80 dipole from 65 feet to 75 feet is highly
> unlikely to change anything discernibly except the feed impedance of
> the dipole, and that not much.
>
> Are you thinking that 75 feet is close to a half wave on 80? A half
> wave for calculating heights and such (not the length of a dipole) at
> 3.5 MHz is around 140 feet.
>
> Get a modeling program. Play around with a dipole, move it up, down,
> tilt it, droop the ends, whatever. Once you get the hang of it a bit,
> you will realize you have been groping in the dark all along.
>
> Eznec 3 costs less than taking four out to a nice restaurant. If you
> are into diddling with antennas and trying to see what if xxxxx, it
> will be the most enjoyable piece of software you ever bought.
>
> 73, Guy.
>
>
> ----- Original Message -----
> From: "Jerry Kincade" <w5kp@swbell.net>
> To: <towertalk@contesting.com>
> Sent: Thursday, May 30, 2002 12:57 PM
> Subject: [Towertalk] Dipole height
>
>
> > Antenna mavens: In addition to a large 10-el F12 tribander, I'm
> running a
> > 121' dipole/balun with it's apex at 65' on a 6' insulated standoff,
> with
> > both ends at about 50'. Sort of a gently inverted V. It works very
> well on
> > everthing between 10 and 80, and absolutely great on several bands.
> The
> > question: If I was willing to sweat a little I could the apex up
> to 75',
> > with the ends at about 55'. Is the extra 10' worth a trip up the
> tower, db
> > wise, on 75 and 80? My thinking was it might work even better if the
> > *average* height were up about a half wave on 80, instead of just
> the apex.
> > All guys are Phillystran, which is probably one reason it works so
> well now.
> > Thanks for your opinions.
> > 73, Jerry W5KP
> >
> >
> >
> > _______________________________________________
> > Towertalk mailing list
> > Towertalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
>
>
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