Topband: Vertical dipoles in the real world

[PaulKB8N at aol.com]

Here is some fresh data on my Vertical Dipole versus my Double Zepp.   This 
was run last night and is typical of the reams of comparison data that  
I've accumulated on 40M.
 
My methodology:  I find a clear frequency, and after a couple of QRLs  make 
a series of three CQ messages, spaced 5 seconds apart.  Once the first  
antenna is checked, I change frequency by a few kHz and repeat the same series  
of CQs with the second antenna.  I alternate which antenna I use first in  
case that might somehow skew the data.
 
I create a printout of the RBN responses and determine which responses are  
common to both antennas and compare those reports.  I also note which  
stations were received by just one antenna or the other.  The data is  
remarkably consistent.
 
Antennas:  180' Double Zepp, 30-35 feet above ground.  This is a  charmed 
antenna.  I've been at this QTH for almost 20 years, and have tried  
countless antenna designs, and this is the best I've ever used, great even on  160M 
considering its length and height.  I have a 40M inverted Vee with  apex at 
40' which rarely beats this antenna.  This DZ is strung  above the route for 
neighborhood underground utilities, and has a road and  green belt in the 
foreground to the east.  This may provide something of a  counterpoise.  I've 
won the Low Power NA Sprint and had numerous top five  and top ten 
performances thanks to this antenna.  
 
The Vertical dipole is 25' long with 42" square hats on top and  bottom.  
It is tied to a tree limb, and is pretty much buried in a stand of  trees.  
It is fed with 300 ohm ladder line.
 
Here is the comparison data compiled between 0303Z and 0305Z.   Vertical 
dipole was the first antenna tested.  Here are the results by  receiving sites:
 
Station        Best  Antenna    dB Difference
DR1A          DZ                   10
F5MUX        VDp                 7
V51YJ         Equal               0
EA4TX         VDp                  2                               
WA7LNW     DZ                   5
N4ZR            DZ                   1
W4KKN        DZ                   6
KM3T            DZ                   3
K1TTT           VDp                  1
WZ7I            Equal                0
NC7J            DZ                    2
K3MM            VDp                4
NQ6N            VDp                 3   
W3LPL          DZ                   1
NY3A              VDp                9
KQ8M              VDp                2
N0TA              DZ                  7
N7TR              Equal              0
N6NC              VDp                4
N6WIN            VDp                1
K8ND               VDp               2
 
Reverse Beacon Reports for only one antenna:
DZ (1)  W8WTS
VDp (3) DL1EMY, WB2LSI, GW8IZR
 
dB advantage over all common stations between antennas (the sum) is equal  
at 35 dB for each antenna!
 
DX advantage:   VDP had the advantage on 2 DX stations, DZ one  and one was 
equal.  Two of the three beacon stations reporting  exclusively on the VDp 
were DX.  The DZ was heard exclusively on only  one reverse beacon, and it 
was stateside.
 
These are completely unexpected results.  I was hoping to find  something 
that would be within a few S units of the DZ to use as a backup, but  this 
antenna is more than its equal.  Daytime results a quite similar,  
surprisingly.  I haven't paid as close attention to them as 40M is a money  band 
primarily at night, but during daylight periods of high absorption,  the DZ seems 
to do 2-3 dB better.
 
I was quite flummoxed after a rare but heavy rainstorm.  The DZ was  
showing an average 5-6 dB advantage shortly after the storm.  I surmised  that 
somehow the wet ground was providing a better counterpoise for the  DZ.  Recall 
I mentioned that the VDp was nested in a stand of trees, that  seemed to 
actually be the problem, as results normalized after two dry days. 
 
If there is one thing I can say with some authority, I know which antennas  
have worked well for me.  I am limited to about 35' max height and 100' max 
 length in my lot (one leg of the DZ goes into the lot of a very awesome 
and  supportive neighbor!).  My antenna effort is the sub optimization  of 
some rather limited choices, when I find something this good, especially when  
it takes so little real estate, it is truly exciting.  My mind now wanders  
to a multi-element array for 40M.   I also wonder how I might apply  this 
concept to a small 160M vertical.
 
YMMV, but I've got abundant evidence that it works for me.
 
Paul, K5AF
 
 
 
 
In a message dated 9/22/2012 12:05:27 P.M. Central Daylight Time,  
armstrmj at aol.com writes:

Well  Tom, all I can say is that it works...... Here is more data.... The 
mast was a  wood pole about 12 feet long and the feedline was buried, so 
there wouldn't be  much radiation from them.  There could be some from the base 
of the  vertical to the dirt via the feedline, but that would be all that 
was  possible.  Well, there could be some while it is buried in the dirt, too, 
 of course..... Not sure how much since I had a current balun close to the  
feedpoint. 

I do try to think of things like incidental radiation in my  setup.  Can't 
always do much about it, but I try.  The point here  was not modeling, it 
was experience..... Of which I have considerable.  I  have used these antennas 
alot (half wave verticals) during my 52 years.   They have never 
disappointed from an actual performance point of view.  I  will say, however, that 
they seemed to work better from Hawaii and my house  was VERY close to the sea 
there almost 360 degrees.  But ANY antenna  seems to work better when 
surrounded by sea water, so that is kind of a  given.

If we are talking a modelling contest, then I haven't got a clue  with all 
the variables.  I can just answer someone who asks if I used  one..... The 
answer is no.... I have used many of them and they ALL worked  well enough to 
make me want to keep them.  That is about a good as I can  say for any 
antenna :) :)  BUT I do hear you, which is why I said what I  did about the 
installation..... All of it may well apply to my success with  the antenna.  

Mike AB7ZU
Kuhi no ka lima, hele no ka  maka

On Sep 22, 2012, at 5:54, "Tom W8JI" <w8ji at w8ji.com>  wrote:

>> A ringo ranger is a vertical half wave using "end feed"  and they work
>> great.  I prefer end feeding, using hte method  of the ringo (which is
>> easy to scale to other bands).  I  purchased the 10 meter version some
>> years back and built ones for  all bands to 20 meters by scaling the
>> end-feed  arrangement.
> 
> When we end-feed a vertical like that, without  radials, the system can 
have as much radiating current on the mast and  feedline as the vertical 
itself has. This can do all sorts of things to the  pattern and gain, because 
the feedline and mast become a major part of the  actual antenna.
> 
> There is a basic electrical rule that cannot  be broken. In order to 
force current up into the vertical at the feedpoint, an  EQUAL current has to 
flow back down into the coax shield, the mast, radials,  or something else.
> 
> We are kidding ourselves if we look at an  end-fed antenna without a 
ground system and proper feed isolation and assume  only the vertical is the 
radiator.
> 
> This is why, later in the  Ringo's life, Cushcraft added a kit that added 
radials to the Ringo.
>  
> 73 Tom 
_______________________________________________
UR RST  IS ... ... ..9 QSB QSB - hw?  BK