That's great, Jim! Give it a try on 40 and 30m as well. You'll be pleased. The
FO0AAA loop, because of its larger area, has a bit more gain than my 40' X 10'
KAZ loop but both are good antennas. I expect that you are going to enjoy it
this winter!
73,
Charlie
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of James
Rodenkirch
Sent: Saturday, September 07, 2013 9:41 PM
To: Charlie Cunningham; topband@contesting.com
Subject: Re: Topband: 5/8 wavelength vertical is mo betta than shorter
versions??
My loop, Charlie, is doing well - it's not a Kaz thingy -- it's a take off on
the FO0AAA delta loop. Seeing 2 to 3 S units of difference when switching from
east to west and listening to a signal of S5 to S7 on 80 meters! On Top Band,
when I can find a signal of average strength I'm seeing about the same.
Finishing up the switching box in the shack - it's a glorified T/R switching
arrangement with some added protection for the pre-amp and a foot switch to
switch transmit and receive (my transceiver doesn't have separate RX and TX
antenna connections)
> From: charlie-cunningham@nc.rr.com
> To: rodenkirch_llc@msn.com; topband@contesting.com
> Date: Sat, 7 Sep 2013 20:00:48 -0400
> Subject: Re: Topband: 5/8 wavelength vertical is mo betta than shorter
> versions??
>
> Hi, Jim!
>
> Good to hear from you!
>
> I don't think there's any simple or definitive answer to your question. The
> reason is that the 5/8 wave vertical splits the radiation into 2 lobes and
> has a second higher angle lobe, compared to a 1/4 wave monopole. Sometimes,
> depending on distance (and skip distance), time of day, frequency,
> trans-equatorial propagation etc. the high angle lobe can add some advantage.
> A similar situation exists sometimes at VHF/UHF in mountainous areas with
> mountain top repeaters, Sometimes the high angle lobe can help out the
> mobiles at lower elevations. Similarly, the mountaintop repeater is better
> using a 1/4 wave or 1/2 wave vertical than 3 or 5 half-waves in phase that
> have gain toward the far horizon, but put less signal down into the valleys
> and hear less well at lower elevation angles. So no simple answers. But,
> after all, we can't reason people out of firmly beliefs that they didn't
> arrive at through reason! :-)
>
> BTW - how's your KAZ terminated loop doing??
>
> Regards,
> Charlie, K4OTV
>
> -----Original Message-----
> From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of James
> Rodenkirch
> Sent: Saturday, September 07, 2013 7:25 PM
> To: topband@contesting.com
> Subject: Topband: 5/8 wavelength vertical is mo betta than shorter versions??
>
>
>
>
> I saw someone post a "my 5/8 wavelength vertical really outperformed my 1/4
> wavelength vertical" a day or two ago.
> I kinda wondered about that (I've "heard" a 5/8 wavelength is mo betta) so I
> did a little digging around.
> From a K3LC paper on tall verticals -
> http://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2011/QEX_5_11_Christman.pdf
> - I found the below:
>
> Performance comparison between vertical antenna systems of varying height,
> when operating on 80 meters at a frequency of 3650 kHz. The monopoles are
> made from no. 10 AWG wire, with a ground screen composed of 60 buried no. 14
> AWG radials (radial length = monopole height). All conductors are aluminum,
> and the soil is “average” (conductivity = 0.005 siemens/meter and dielectric
> constant = 13).
> ¼ λ System 3⁄8 λ System ½ λ
> System 5⁄8 λ SystemMonopole Height and Radial Length (ft)
> 67.368 101.05
> 134.74 168.42Input Impedance (Ω) 41.4 + j 24.4
> 229 + j 605 2324 – j 1425
> 86.1 – j 479SWR (50 Ω ref.) 1.75
> 36.8 64.0
> 55.5Peak Gain (dBi) and Take-off Angle (°)0.39 at 24.7
> 0.79 at 21.7 0.96 at 17.6
> 0.42 at 13.3Gain (dBi) at 5° Take-off Angle–5.21
> –4.34 –3.42
> –2.81Gain (dBi) at 10° Take-off Angle –1.70
> –0.91 –0.14
> 0.06Gain (dBi) at 15° Take-off Angle –0.32
> 0.35 0.85
> 0.34Gain (dBi) at 20o Take-off Angle 0.25
> 0.76 0.89
> –0.63Half Power Beamwidth (°) 43.7
> 38.0 29.0
> 20.3Efficiency (%) 33.8 34.3
> 29.6 29.8
>
> Performance comparison between vertical antenna systems of varying height,
> when operating on 40 meters at a frequency of 7150 kHz.
> The monopoles are made from no. 10 AWG wire, with a ground screen composed of
> 60 buried no. 14 AWG radials (radial length =monopole height). All conductors
> are aluminum, and the soil is “average” (conductivity = 0.005 siemens/meter
> and dielectric constant = 13).
> ¼ λ System 3⁄8 λ System
> ½ λ System 5⁄8 λ SystemMonopole Height
> and Radial Length (ft) 34.391 51.586
> 68.781
> 85.976Input Impedance (Ω) 39.9 + j 25.0 235 + j
> 570 1937 – j 1247
> 81.9 – j 436SWR (50 Ω ref.) 1.81
> 32.5 54.8
> 48.7Peak Gain (dBi) and Take-off Angle
> (°) 0.15 at 26.2 0.68 at 23.3
> 0.89 at 19.1 0.68 at
> 14.5Gain (dBi) at 5° Take-off Angle–6.15 –5.15
> –4.13
> –3.12Gain (dBi) at 10° Take-off Angle –2.38
> –1.44
> –0.56 0.08Gain (dBi) at 15°
> Take-off Angle –0.82 0.02
> 0.66
> 0.67Gain (dBi) at 20° Take-off Angle –0.11
> 0.59 0.88
> 0.04Half Power Beamwidth (°) 44.1
> 39.3
> 30.7 22.3Efficiency (%)
> 31.9 34.0
> 30.4 31.7
> Performance comparison between vertical antenna systems of varying height,
> when operating on 20 meters at a frequency of14.175 MHz. The monopoles are
> made from no. 10 AWG wire, with a ground screen composed of 60 buried no. 14
> AWG radials (radial length = monopole height). All conductors are aluminum,
> and the soil is “average” (conductivity = 0.005 siemens/meter and dielectric
> constant = 13).
> ¼ λ System 3⁄8 λ System ½ λ
> System 5⁄8 λ SystemMonopole Height and Radial Length
> (ft) 17.347 26.020
> 34.694 43.367Input Impedance (Ω) 39.0 +
> j28.4 247 + j536 1595 –
> j1070 77.4 – j392SWR (50 Ω ref.) 1.97
> 28.3 46.3
> 41.8Peak Gain (dBi) and Take-off Angle (°) 0.29 at 27.1
> 0.91 at 24.3 1.16 at 19.9
> 1.21 at 15.0Gain (dBi) at 5° Take-off Angle –6.35
> –5.28 –4.18
> –2.86Gain (dBi) at 10° Take-off Angle –2.46
> –1.45
> –0.49 0.48Gain (dBi) at 15° Take-off Angle
> –0.8 1 0.1
> 1 0.84 1.21Gain (dBi) at 20° Take-off
> Angle –0.04 0.76
> 1.16 0.70Half Power Beamwidth
> (°) 44.4 40.4
> 31.5 22.8Efficiency (%) 32.9
> 36.3
> 32.9 34.7
> The above modeling results just don't support that contention/posit so I'm
> wondering what else comes in to play that could lead folks to love the 5/8
> wavelength vertical over a shorter version, regardless of frequency? I don't
> see one performance comparison that supports that claim. I'm not saying the
> "claiming person" isn't correct but....I don't see how!
> Help - what am I missing here?
> 72, Jim Rodenkirch K9JWV
>
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> Topband Reflector
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