[TenTec] Radial Research

[Richards]

On 5/21/2012 4:37 PM, Stuart Rohre wrote:

> If your local soil varies so much that your radial currents are not
> balanced, the effect will likewise alter your pattern, but that does not
> prevent the vertical from working as expected, it just may favor one
> direction over another, slightly.
		
> The variations in the propagation has a much greater effect on the
> signal and for that we have no control, once the signal leaves the
> antenna.


		Of course, we also have little or no control
		over the ground conditions under the stick	.

		For that reason, if I ever get the chance... I will
		pull up the sod and lay a huge ground screen made
		of welded galvanized fencing, heavy duty lawn fabric
		or the like following Rob Sherwood's example - but even
		more extensive than he did !   	I would have laid some
		of that when I put up my big stick, but (as you suggest)
		the ground under my stick is far from even - either in
		composition or elevation - and I could not imagine how
		I would get it to lay flat enough to work its way into
		the thatch over time.   That stuff could really wreck
		my wife's mower if it did not lie flat and disappear
		like wire does.   I certainly don't wanna have to
		start doing the lawn MYSELF !

And seriously folks...

		All this talk about the 43 foot vertical... just makes
		me wonder how much better something TUNED and
		somewhat RESONANT - LIKE THE HY-GAIN HI-TOWER -
		might work over a nice, sweet radial field.   This is
		one of the reasons I shortened my 43 footer to a 33-
		foot 40 meter ground plane.   I am wondering whether
		it will work any better as a tuned, resonant ground plane,
		than 	a somewhat larger non-resonant stick.  I am curious
		to discover whether the added gain from being longer
		outweighs or sufficiently counters the added losses
		from higher SWR in the coax and 4:1 Un-Un.

		Time will tell, but it was way cool to stick the analyzer
		on it and have a 1.35 - 1.38 SWR all across the 40 meter
		band,  with text-book 38 ohm impedance.    AT 43 feet,
		it showed 6.8 SWR (without Un-Un) and 2.5 SWR
		(with Un-Un).

		Should be fun finding out.


Most of the signal influence once radiated depends on the
> earth out beyond the Fresnel Zone, some 5 wavelengths beyond the antenna
> location and usually out of the ham's control as to what is on the earth
> at that distance---buildings, ponds, different terrain or elevation.


		Fresnel Zone...!  Sheesh!
		Now you gotta go and complicate matters !   I was
		just getting a handle on the Pseudo Brewster angle...
		and now you gotta throw some other nonsense into
		the mix !

		Er... um...   just kidding...    ;-)

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