[amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs

[i8cvs]

Hi Art, KC6UQH

I would like to receive from you copy of the Microwave Journal December 1970
Pgs 49-54 By Doctor CC Kilgus about the QFH Antennas.

Tanks

73" de

i8CVS Domenico

----- Original Message -----
From: "Art McBride" <kc6uqh at cox.net>
To: "'i8cvs'" <domenico.i8cvs at tin.it>; "'AMSAT-BB'" <amsat-bb at amsat.org>;
"'Franklyn A. Ballentine, jr'" <art.ballentine at gmail.com>
Sent: Thursday, October 01, 2009 7:09 AM
Subject: RE: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design
specs


> The most comprehensive info on QFH antennas is the Microwave Journal
> December 1970 Pgs 49-54 By CC Kilgus.
>
> Art, KC6UQH
>
> -----Original Message-----
> From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On
> Behalf Of i8cvs
> Sent: Wednesday, September 30, 2009 5:35 AM
> To: AMSAT-BB; Franklyn A. Ballentine, jr
> Subject: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design specs
>
> Hi Frank, KB1QZH
>
> The best starting point is the original article of the inventor of QHA i.e
> Walter Maxell, W2DU
>
> In a separate email I have attached the above fundamental article.
>
> 73" de
>
> i8CVS Domenico
>
> ----- Original Message -----
> From: "Franklyn A. Ballentine, jr" <art.ballentine at gmail.com>
> To: "i8cvs" <domenico.i8cvs at tin.it>
> Cc: "AMSAT-BB" <amsat-bb at amsat.org>
> Sent: Tuesday, September 29, 2009 6:45 PM
> Subject: Re: [amsat-bb] Re: quadrafilar helix for 70cm- ambiguous design
> specs
>
>
> I have a question along the same line.  Is the QHA in the ARRL
> Satellite Handbook \ Antenna handbook, a good starting place?
>
> Thanks,
> Frank B.
> KB1QZH
>
> On Tue, Sep 29, 2009 at 11:17 AM, i8cvs <domenico.i8cvs at tin.it> wrote:
> > ----- Original Message -----
> > From: "Tim Goodrich" <tim at timgoodrich.net>
> > To: <amsat-bb at amsat.org>
> > Sent: Monday, September 28, 2009 9:45 PM
> > Subject: [amsat-bb] quadrafilar helix for 70cm- ambiguous design specs
> >
> >> Hi All,
> >>
> >> The house I just bought precludes me from even using my arrow inside as
> >> there must be something un-RF friendly in the walls. Therefore, I was
> >> looking for a roof antenna and the October QST article on the QFH
> inspired
> >> me to build one. However, after doing some research, I have come up
with
> > two
> >> sets of design specs and I'm unsure which one is correct.
> >>
> >>
> >>
> >> I converted everything from you're the 146Mhz QST model to 436Mhz.
> > However,
> >> when I plug that info into http://www.jcoppens.com/ant/qfh/calc.en.php
> >>
> >> The values it puts out are different in the "compensated length" field.
> > The
> >> only difference is this model calculates for a full turn as opposed to
a
> >> half turn, but the lengths shouldn't be as different as it says. Under
> the
> >> QST model, I get a wavelength of 688mm, but under the website's model,
it
> >> gives me a "compensated wavelength" of 729mm.
> >>
> >>
> >>
> >> The values I used to calculate are:
> >>
> >> 436
> >>
> >> 1
> >>
> >> 1
> >>
> >> 15
> >>
> >> 2
> >>
> >> .23
> >>
> >>
> >>
> >> Can anyone tell me which specs to use and/or explain this compensated
> >> wavelength issue?
> >>
> >>
> >>
> >> Thank you,
> >>
> >> Tim
> >>
> >> KI6VBY
> >>
> > Hi Tim, KI6VBY
> >
> > Read please the book "REFLECTION" Transmission Lines and Antennas by
> > M. Walter Maxwell, W2DU Chapter 22 The Quadrifilar Helix Antenna pages
> > 22-1 to 22-23 and also
> > "Experimental Investigation of Quadrifilar Helix Antennas for 2400 MHz"
> The
> > AMSAT Journal May/June 2004
> > In a separate email I have sent to you both articles as an attachement.
> >
> > 73" de
> >
> > i8CVS Domenico
> >
> >
> >
> > _______________________________________________
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> >
>
>
>
> _______________________________________________
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