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-boun...@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-cunning...@nc.rr.com > To: rodenkirch_...@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-boun...@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 > > _________________ > Topband Reflector > > _________________ > Topband Reflector _________________ Topband Reflector _________________ Topband Reflector