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Re: Topband: 5/8 wavelength vertical is mo betta than shorter versions??

To: "'James Rodenkirch'" <rodenkirch_llc@msn.com>, <topband@contesting.com>
Subject: Re: Topband: 5/8 wavelength vertical is mo betta than shorter versions??
From: "Charlie Cunningham" <charlie-cunningham@nc.rr.com>
Date: Sat, 7 Sep 2013 22:15:08 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
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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