Topband: More anecdotal "stories" to cause one to stop and....

[Tom W8JI]

> But then if you overlay the two models you see something very strange. The 
> Total radiation of the horizontal antenna (against normal ground, not sea 
> water) is so much better that its effective radiation at low angles is 
> about the same as the vertical. At most it's down 6 dB at 5 or 10 degrees 
> depending on ground conditions, radial fields etc. When I model it I 
> actually see less than this difference in my location.
>
> So the fact that you can be heard by DX on a low horizontal isn't all that 
> amazing. You have to have a pretty ideal vertical set up to beat it by a 
> lot.
>

Part of the problem with that and some of the other models floating around 
is EZNEC does not calculate very low angle signals on low frequencies very 
well. We have to be careful with that, and the overuse of TOA. EZNEC 
calculates at a very large distance along flat perfect ground. I can't 
recall the exact distance, but perhaps it was something like 500 
wavelengths? I'm only guessing, but it is a large distance. 500 wavelengths 
is 50 miles away over flat earth, so groundwave and low angles looks like 
zero when they are really not. On ten meters, that's only 3 miles or so. It 
is more realistic on higher frequencies. Someone else probably knows the 
exact answer.

As an example though, EZNEC shows FS of a vertical as virtually zero at zero 
degrees. We know that isn't true.

This also messes up the TOA, which pretty useless number anyway.

That aside, if we look at statistics from hundreds of people on 160, most 
people favor verticals of some type for the best overall results. There is 
good reason for that, and it is more than lack of room for antennas.

I did hundreds and hundreds of blind tests from here, and horizontals are 
competitive only at sunrise or sunset or during severe magnetic storms. 
There are people who report exceptions, but that small number could be a 
location or installation anomaly.

VK3ZL and I did thousands of comparisons over many years. As I recall Bob 
was convinced a low dipole was the only answer, but he later changed to 
favoring his vertical. Both his vertical and dipole are height limited, and 
he is in a location where supposed the dipole should have an advantage.

I had multiple verticals, and dipoles at low (100 foot or so) and high (300 
foot or so) heights. The dipole at 300 feet should, on paper anyway, kill 
the verticals. It never did. No one contesting here ever wants to use the 
dipoles, and I almost never found them better for anything except within 200 
miles (the low dipole). The high dipole had almost no local signals (out to 
maybe 200-500 miles) and was never really better for DX. At sunrise or 
sunset, or during geomagnetic storms, all the antenna would get pretty even. 
On other rare occasions when the dipole would be better, I was still plenty 
loud on the vertical. When the vertical was weak, the dipoles were generally 
totally useless.

W0BTU probably remembers when I was playing with antennas in NW Ohio on King 
Road. King Road was in a black sandy loam marsh, there was almost always 
water mixed with black soil, and there was a 355 ft tower I had access to. I 
was convinced a dipole at the tower top worked great, but when I finally A-B 
tested that dipole against a 1/4 wave tower at my house a few miles away, 
the vertical was pretty much equal or better.

Taller verticals or verticals that focus at low angles have consistently 
been underachievers also. While they make contacts, just as a high or low 
dipole does, they are never better and more often than not they are 
significantly worse for most contacts.

This is just how it was for me based on years and years of trying different 
things at three or four different locations.

If someone has the room and one antenna does not bother the others, there 
certainly can be an advantage to a range of antennas. But some of the most 
unreliable unpredictable oddly behaving antennas come from too many antenna 
on top of each other. I remember W8LNV just blowing up at K8GIJ for running 
an amplifier, when GIJ just had a pair of 6146's and less power than LNV. 
This is because LNV had a mess of antennas and wire in a 50x200 foot back 
yard, and Harold had one zepp fed as an inverted L on 160 (a very clean 
install). Harold had a 10 or 20 foot deep backyard, about 100 feet long, and 
was always within an S unit of my 1/4 wave tower over 120 radials.

It all depends an awful lot on how people do things.

73 Tom