[Antennas] Would vertical be better than yagi? Maybe...

[K6MHE]

Charles,

I have been following this with some interest however I am wondering if you 
are comparing a *vertical* dipole to a *horizontal* Moxon Rectangle? If so 
I would expect the "takeoff angle" to be different. I wondering you modeled 
the Moxon in the vertical or horizontal position? In other words are you 
truly comparing a dipole and yagi in alike curcumstances?

Danny, K6MHE

   At 06:55 AM 6/12/2002 -0400, you wrote:
>Karl and All,
>
>I'm sorry I have to disagree with you Karl.  One big advantage of a Yagi 
>compared to a dipole, is it's take off angle is lower.  I modelled the 
>field day Moxon Rectangle antenna in June 2000 QST for 40 meters with 
>EZNEC, and also modelled a vertical and dipole at the same height for 
>comparison purposes. A Moxon Rectangle is a two element beam with the ends 
>folded toward the center.  Results:
>
>         Vertical angle
>         of maximum radiation           Gain
>
>1/4 Vertical         22 deg            -.59 dBi
>
>40 meter dipole      62 deg            6.61 dBi
>at  37 ft.
>
>Moxon Rectangle      45 deg            9.55 dBi
>at 37 ft
>
>The antenna is for 40 meters but a similar comparison can be made for 
>higher frequencies.  Actual results may vary, but the advantage of the 
>beam with respect to gain and take off angle is readily apparent.
>
>For actual results, I have a G5RV at 30' and its gain is about the same as 
>my Hustler 6BTV vertical on 20 on US stations but slightly better on 
>DX.  The gain of the G5 is slightly greater on 40.  I don't have a 
>comparison on the other bands except to state that they both work about 
>the same.
>
>73's
>
>At 05:55 PM 6/11/2002 -0500, Karl Kanalz wrote:
>>Actually, John, if you look at the elevation patterns ("take-off angle")
>>of a Yagi antenna, you'll find that the take-off angle of a Yagi is the same
>>as a dipole at the same height!  The major difference is that the Yagi has
>>(usually) a front-to-back and front-to-side ratio that the dipole *doesn't*
>>have,
>>and that's why it produces "gain" over the dipole.
>>
>>Your particular "... lack of height..." is why your Yagi is not performing
>>as
>>expected.
>>
>>If you'll read the appropriate sections of the ARRL "Handbook" or the
>>ARRL "Antenna Book", you'll begin to understand the importance of
>>height above ground for *any* antenna, and how it affects the radiation
>>pattern, the "take-off angle" and so on......
>>
>>Karl K - W8TIF
>>McKinney, Texas
>>
>>-----Original Message-----
>>From: John Geiger
>>Sent: Tuesday, June 11, 2002 3:04 PM
>>To: antennas@mailman.qth.net; dx-list@yahoogroups.com; dx@mailman.qth.net
>>Subject: would vertical be better than yagi?
>>
>>I recently put up a 2 element triband yagi (full size
>>tribander) but it is not up very high-maybe 25 feet or
>>so.  The lack of height is noticable in performance.
>>It does show gain towards Europe vs my dipole (G5RV
>>type, also not up very high), and it also showed gain
>>over the dipole when working VK9LO the other day.
>>SOmetimes the yagi is a couple of S units better than
>>the dipole towards Europe.  Most of this has been done
>>on 20 meters.  Have not found enough stuff on 10 to
>>compare yet.
>>
>>However, the past few days been trying to work BQ9P
>>for #298, and the yagi doesn't show much gain at all
>>over the dipole towards the far east-observe the same
>>with Japan.  Did work DU3NXE on 20 cw this AM with the
>>yagi, but he was about as loud on the dipole.
>>
>>THe way I understand it, the low height does not give
>>me the low angle radiation lobes that the long haul DX
>>often requires.  So my question is:  Given that I
>>might not be able to get the Yagi much higher for some
>>time (my yard is a nightmare of trees and power lines)
>>would I be better off getting a vertical on the roof
>>instead.  I know that verticals hear equally poor in
>>all directions, but would it allow me to get the lower
>>angle-long haul stuff.
>>
>>I would appreciate any comments, especially from those
>>who have been in the same boat.
>>
>>73s John NE0P
>
>73, Chas, W1CG
>
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