I have the complete article from '79 HR if anyone is
interested.
Jeff
k4bp@arrl.net
--- Steve Katz <stevek@jmr.com> wrote:
> The actual article to which ZL1DD refers is in the
> May 1979 issue of Ham
> Radio magazine, and entitled, "Quads vs. Yagis
> Revisited," by Dr. Wayne
> Overbeck, N6NB. A photo from that article, and a
> little writeup about it
> can be found at:
>
>
http://commfaculty.fullerton.edu/woverbeck/antgain.htm
>
> (scroll down, the reference is near the bottom of
> this section)
>
> I knew Wayne well (still do) at the time he did this
> research and wrote the
> article, and he traveled all over southern
> California with an LM470
> motorized tower trailer (70' tower) and TH2 Hy-Gain
> 2L trapped yagi, not
> known for its stellar performance. He would park in
> the driveways of, or in
> front of the homes of, noted DXers using cubical
> quad antennas, typically
> also up about 70 feet, and do one-on-one, on-air
> comparisons in real time.
> In virtually every case, the station/quad owner was
> shocked to find his quad
> worked no better (and normally no worse) than the
> little 2L yagi, on short
> paths, long paths, and all paths. It was a very
> good article, since it was
> well documented with lots of photographs and the
> callsigns of the DXers who
> participated in the research. -WB2WIK/6
>
> "If everything seems under control, you're just not
> going fast enough." -
> Mario Andretti
>
> > -----Original Message-----
> > From: Barry Kirkwood [SMTP:bjk@ihug.co.nz]
> > Sent: Monday, November 18, 2002 1:49 AM
> > To: Tower Talk
> > Subject: [Towertalk] Quad vs Yagi
> >
> > I know of but one comparative study of quads and
> yagis in the field that
> > seems to me to meet scientific standards.
> > Cannot remember the reference, but it was in Ham
> Radio a long time ago.
> > Method:
> > Two element trap tribander used as comparison
> antenna with truck mounted
> > telescoping tower.
> > Comparison antenna could be used at same height on
> same site as test
> > antenna.
> > Criterion was forward gain.
> > Across the bands the trap tribanders looked rather
> bad. Away from optimum
> > frequency the larger trap antennas often did worse
> than the reference
> > antenna.
> > Two element quads did better than monoband yagis
> of same boom length, in
> > line with theory which predicts ca 1.8 dB better.
> > Longer multielement quads tended to underperform
> by comparison with
> > monoband yagis of the same boom length.
> > Note:
> > (i) This was before antenna modelling programs
> were widely available. It
> > may be possible to optimise the performance of
> longer quads, as witness
> > some exercises reported in QEX in recent years.
> > (ii) The larger tribanders would have given better
> f/b and narrower
> > beamwidth compared to the smaller tribander even
> though forward gain was
> > mediocre. This would give advantage on receive and
> if ample TX power was
> > available the overall communication capability of
> a staion so equipped
> > would be satisfactory to most users.
> > (iii) The case Force 12 makes for horizontally
> stacked full length element
> > tribanders is based on sound science.
> > (iv) Data published in RSGB Radio Communication
> suggests that the
> > Cushcraft triband yagi with a log cell driven
> element is underperforming
> > on 28mHz.
> > (v) Speaking generally, as the good Dr Cebik
> shows, modern modelling
> > programs have good success in matching real world
> antennas of the sort
> > under discussion.
> > (vi) Claims of x% loss for various configurations
> should at least be
> > supported by data from modelling if they are to be
> taken seriously.
> > 73
> > Barry
> >
> > end
> > Barry Kirkwood PhD ZL1DD
> > Signal Hill Homestay
> > 66 Cory Road
> > Palm Beach
> > Waiheke Island 1240
> > NEW ZEALAND
> > ph/fax 64-9-372-5161
> > www.waiheke.co.nz/signal.htm
> >
> > --- StripMime Report -- processed MIME parts ---
> > multipart/alternative
> > text/plain (text body -- kept)
> > text/html
> > ---
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