Topband: 5/8 wavelength vertical is mo betta than shorterversions??

[Tom W8JI]

),
> I am well aware that my comments concerning the 5/8ths wave was based upon 
> subjective/anecdotal evidence.  I am in a science (Astrophysics) by 
> profession..... I do know the difference.  HOWEVER, I cannot completely 
> throw out the simple fact that when I altered my 20 meter omni antenna for 
> Winlink to the 5/8ths, that I received UNSOLICITED comments from the 
> system users stating (100 percent of them) that my signal was much 
> improved into the areas they happened to be sailing.  None of those 
> people, not a single one, knew that I was changing my antenna.  The 
> purpose being just that..... to see if anyone complained or said anything 
> else concerning performance from THEIR point of view.  In reality, THAT is 
> the point when supplying a service..... What do the USERS think of the 
> performance, not what I think or what a FS meter says.
>

.....but this is 160, and it behaves much different than 40 meters, let 
alone higher bands, so I tend to only comment on the 160 part of things 
unless something applies across the board.

 >
> As an aside, alot of folks are using that so-called non-resonant vertical 
> antenna that is roughly 43 feet tall....... They seem to be having some 
> success with them on the bands.  Physically, they are pretty 
> convenient..... and on 20 meters, they happen to perform pretty well, 
> judging from user comments, anyway..... and at that band, it is roughly 
> 5/8 wave in electrical height.  So, again, I find it interesting that 
> actual experience argues with the modelling software (in MY particular 
> instance).  >>

Any model I've tried has always been right when I do things correctly, and 
understand the requirements of a band. I've had a lot of experience with 
5/8th waves on 160, and taller antennas, and have painfully learned some of 
the pitfalls of using models. For example, EZNEC undercalculates low angle 
gain because it calculates at a considerable distance from the antenna. I 
generally ignore that problem because we don't use groundwave, and after 
years and years of operating with various antennas I'm pretty well convinced 
exceptionally low wave angles are not very useful.

I can't think of anyone ever, since I first got on 160 in the early 1960's, 
who has seen an overall improvement from compressing vertical elevation 
pattern much lower than a 3/8th wave provides on 160. Some things come to 
mind from history, like the weak signal and poor results of W8LT in 160 
contests. Another are the hundreds or thousands of blind AB and ABC tests 
with people on 160 I have done. I chose to not use my tall tower as a 
vertical on 160 because of those results.

Also, nearly all gain in a stack of a 1/2 wave vertical over a 1/4 wave, or 
a 1/4 wave over a 1/4 wave, does NOT come from the stack. Virtually ALL of 
the gain comes from the current in the higher element and the earth 
reflection. If you build a stack of a 1/2 wave vertical over a 1/4 wave 
vertical, and if the 1/4 wave bottome vertical is completely removed, gain 
is almost the same.

The lower element mostly serves to suppress the higher angle lobe.

This is why the 5/8th wave is a good analogy. Ignoring getting above local 
ground clutter, the 5/8th wave obtains gain from distant ground 
"reflection". A stack of a 1/2 over a 1/4 is nothing more than a 5/8th wave 
with 1/8th wave more current maximum height, and the current "turned around" 
in the lower section so the lower 1/4 wave cancels the higher angle lobe. 
There is NOT a significant contribution to field at low angles, or 
modification of low angles, by the presence of the lower 1/4 wave.

Pretty much only Hams, or Ham based companies or designers, have such an 
overpowering fascination with the 5/8th wave radiator. Most commercial 
designs created by designers, those who actually understand radiating 
systems, use ~1/2 wave or shorter elements. The 43-foot vertical is an 
engineering marvel, just like a new 40-10 meter "groundplane" that has its 
roots from the same design source. It is a religious or political figure 
more than an actual antenna. As such, people really love it and it does all 
sorts of wonderful things. Even if it was killing them, they would follow it 
blindly.

Only L. Ron Hubbard could have invented better antennas.

73 Tom