[TowerTalk] 4-Square Owners & Experts "& resonant trees..."

[Tom Rauch]

> Date:          Thu, 07 May 1998 09:20:15 -0400 (EDT)

> K1VR: Dana Atchley, then W1HKK and later W1CF, who held the patent on the
> four square (along with W1FC, formerly W1FRR), believed that the key was
> not vertical vs. horizontal at 40 m, but rather the ground losses
> inherent in a vertical phased array design vs. losses associated with
> horizontal antennas. He felt that even on 80 meters, a 3 el. Yagi would
> always beat a 4 square (and WA1EKV, now K1KW proved it).

Four squares traditionally use less than optimum gain phasing 
systems. The excellent phasing system described by Roy Lewallen 
(no splitter) uses 90 degree / 180 degree phasing that still has 
the null at zero degrees off the back, producing a broadly focused 
front lobe. The phasing systems alone gives up some gain.
(I use 125/250 degree shift in my four square.)
 
All that aside, the yagi does have an advantage of having a few dB 
more gain due to less ground loss. (The often mentioned six dB 
enhancement of a horizontal antenna is the absolute theoretical 
maximum at one optimum angle for a given height with perfect lossless 
ground none of us have) 

But no disagreement the yagi would have more gain if the loading 
scheme didn't suck up too much power. The vertical relies on ground 
reflection at a longer distance and longer grazing angle to form 
patterns, and so has a larger and lossier Fresnel zone. (The Fresnel 
zone is the entire area where the pattern is being formed, not one 
set distance. It is different for every different system, just 
like near field distance is.) 

> Putting it another way, if you have a signal on 160 which is DOWN 1 dB
> from a half-wave dipole a half-wave high, you have a SPECTACULAR signal!

I was asking if anyone else notices what appears to be progressively 
MORE advantage to the dipole over a ground mounted vertical as 
frequency is raised, all other things equal. For example, on 160 a 
1/4 wl vertical would often equal and at times beat a 260 ft high 
dipole for DX. That's why I quit driving a mile to operate 160.

On 80, I can A-B  a dipole at 110-120 feet and a 70 ft vertical. The 
vertical ties it for almost any contact over a few hundred miles. 

On 40, a 1/4 wl ground mounted vertical never beats a dipole at 70 
ft, unless the station is off the end of the dipole.

I suspect a ground mounted (or near ground mounted) vertical works 
poorer on increasing frequencies compared to a dipole.

I've also had a trap vertical mounted on the support mast at the 
center of a five element monoband yagi (at about 150-160 ft). When I 
would A-B that yagi against the vertical, or the vertical against a 
40 meter rotatable phased array with 70 ft long elements at 140 ft, 
the signal difference was about ten real dB (as opposed to S unit 
dB's) on 20 and always less than five or six real dB on 40. By that 
difference, it appears a very high vertical is about equal to a 
very high dipole.

(As a matter of fact, my usual 20 meter DX ragchewing operation was 
transmitting on the vertical and receiving on the yagi, so the QRM 
off the sides and back of the yagi wouldn't take over. I called it my 
"Florida filter")

73, Tom W8JI
w8ji.tom@MCIONE.com

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