Topband: Elevated radial number vs efficiency

[Artek Manuals]

I have taken the liberty to move Jim's most recent reply on the Common 
mode thread over here where it is more on topic

Jim:
True enough

There is a work around however

Dick Weber k5UI ( SK ..I think) published an article in Communications 
Quarterly in 1999 on an approach using non resonant ( i.e not .25 
wavelength ) radials which significantly reduces the impact of 
unbalanced radial currents. I cant find a link to a copy on the WEB, I 
have a copy of the article (contact me off list) if you cant find one . 
Running four 100 foot radials ( ~.2 wavelengths) I am able to have 
(measured)� radial currents that vary less than 2% over all four radials 
installed in a heavily wooded environment where some attempt was made to 
try and keep all of them "around " 7' above ground

At .2 wavelengths N6LF's work suggests that I am giving up around .2db 
...which suggests I might want to look at going from 100' radials to 150 
/160' ? Will have to look at that, it would require I redo all my 
matching networks not sure I want to go through that for .3db ...8^(

NR1DX
manuals at artekmanuals.com

On 1/1/2021 4:28 PM, Jim Brown wrote:
> On 1/1/2021 12:09 PM, Mike Waters wrote:
>> I am ONE of the people who claim that four elevated radials can have
>> approximately the same efficiency as 120 buried quarter wavelength 
>> radials.
>
> N6LF's work on this showed that imbalance of the current in elevated 
> radials can significantly reduce field strength. Imbalance can be 
> caused by differences in heights, lengths, and soil underneath them. 
> Depending on our real estate, hams may find it difficult or 
> impractical to install elevated radials having the symmetry of a 
> broadcast station. Rudy has published work showing that 8 elevated 
> radials are better than 4 for this reason.
>
> 73, Jim K9YC


On 1/1/2021 4:55 PM, Mike Waters wrote:
> Thanks for catching that, Dave!
>
> I certanly can't argue with Rudy N6LF, but those two λ/4 10' high elevated
> radials in my old 160m page made that inverted-L a "killer"* in an ARRL 160
> contest about 10 years ago. That was using only 100 watts. Broke a number
> of DX pileups, to my utter amazement.
>
> *Having said that, I had nothing else to compare it to in an A/B test!
>
> 73, Mike
> W0BTU
>
> On Fri, Jan 1, 2021, 3:37 PM Artek Manuals <Manuals at artekmanuals.com> wrote:
>
>> Correction that should be N6LF (not N6FL)
>>
>> NR1DX
>>
>> On 1/1/2021 4:26 PM, Artek Manuals wrote:
>>> N6FL was quoted earlier ...
>>> https://www.antennasbyn6lf.com/design_of_radial_ground_systems/
>>>
>>> However N6FL states "The article is primarily intended to show why I
>>> (he, N6FL)
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector

-- 
Dave Manuals at ArtekManuals.com www.ArtekManuals.com

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