Topband: Elevated radial number vs efficiency

[Jeff Blaine]

On N6LF web page you can find the QEX series on ground mounted radials.  
And there is a ton of discussion of this topic on the reflector as it 
seems to come up often (may be mixing it with the towertalk reflector).

73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com


On 1/1/21 11:28 PM, List Mail wrote:
> Yes, the antenna modelling is helpful, but by no means definitive.
>
> Several years ago I put up a top loaded vertical over a very limited 
> buried radial field, 16 x 20 m. It worked, but nothing exciting. It 
> was very hard work burying wire in very hard ground.
>
> I then put up an elevated radial system, starting with a pair, tuning 
> them like a dipole. Same with the second pair. After four, the tuning 
> didn't seem at all sensitive. I ended up with 7 x 1/4 wave radials, 
> plus a shorter one where the property boundary was too close.  The 
> radials were about 2.5 m high, just high enough to not touch with my 
> outstretched hand. That seemed to work quite ok, compared with a full 
> wavelength doublet antenna up 20 m.
>
> I then moved and set up the top loaded now trapped vertical over 
> elevated 4 x 1/4 wave radials for 160 and 4 x 1/4 radials for 80 m. I 
> quickly tired of repairing fallen radials where a horse had rubbed on 
> a post or where I caught the wire on the tractor exhaust pipe! Again, 
> it worked me a decent amount of DX. And I mean "DX" as nearly 
> everything is a very long way from VK3.
>
> Last year, I did the work of burying 60 x 33 m radials, clearing away 
> the mess of overhead wires. Does that work any better than the 
> elevated radials? I cannot know, as there was no means of comparative 
> testing. But, it's a whole lot tidier with the wires under the ground 
> than overhead.
>
> My conclusion is that elevated radials do work quite decently, and 
> they are probably a little less work than burying a decent radial 
> field. Wires on the ground were never an option, with livestock in the 
> paddock. My suggestion, and the references too, is to put the elevated 
> radials up as high as practicable (higher than I had them). This 
> allows easy access to vehicles to drive under them, without tearing 
> something down.
>
> The aim of the radials is to reduce the effect of ground return path 
> losses, and even with 8 radials, I could drive under them, listening 
> to Radio National on 621 kHz, and the signal would be significantly 
> attenuated. All of the above observations were over fairly poor 
> ground, decomposed granite, with granite rocks floating. There is 
> water underlying, however.
>
> 73, Luke VK3HJ
>
>
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