[TowerTalk] High power 2:1 transformer was Re: 16om vertical and the number of radials

[Artek Manuals]

If you read N6LF's work closely (see fig16 in 3/2012 QEX) you will see 
that radial height above 5' adds a few 10ths of a db improvement at 
most. (8ft =.015 wavelength above ground) Given noise and QSB on 160 
hardly worth the effort ..IMO.  Ditto on the number of radials more than 
4 at a reasonable (8') height buys very little as well. What is actually 
more important is soil conductivity  Rich farm loam vs sandy Florida 
(Fig 15)  is worth 5DB !!! I cant imagine trying to keep sixteen 134' 
radials 20 feet in the air !

Another good read on elevated radials ( non resonant radials) that 
doesn't get much play is by K5IU, "Optimal Elevated Radial Vertical 
Antennas" , Communication Qrtly, spring 1997. If Google is not your 
friend contact me off list and I will send you a copy.

Dave NR1DX


On 12/3/2022 2:17 PM, Jim Brown wrote:
> On 12/3/2022 10:20 AM, Chuck Dietz wrote:
>> Thanks for the info. I think I am going with 60 radials on the ground. I
>> want to use the 160 vertical tower to support an 80 meter array 
>> around it.
>> Elevated radials might make adjustments way more complicated. 
>
> It's worth studying N6LF's work on elevated radials. He stresses that 
> keeping radial currents equal reduces loss, that making them slightly 
> shorter than resonant helps that, and so does having MORE elevated 
> radials -- for example, 8 is better than four. From N6BT, I learned 
> that elevated radials for 160M should be at least 16-20 ft high; I 
> learned that when I asked him why my 4 ft high radials weren't working 
> well.
>
>> I have a
>> tractor and a good welder guy to weld a bracket and tube to a single plow
>> shear to make a radial plow.
>
> Remember that the only virtue of burying radials is to protect them 
> from damage, or from being a trip hazard. We are NOT trying to couple 
> the antenna to the earth. The function of radials is to SHIELD the 
> field produced by the antenna from the lossy earth, and to provide a 
> low resistance path for the antenna's return current IN PLACE OF THE 
> LOSSY EARTH.
>
> Radials DO couple to the earth, and the ground loss shows up as series 
> resistance. But radial current divides by the number of radials, power 
> loss is I-squared R, so gets smaller in each radial twice as fast as 
> the number of radials is increased, so more radials reduces loss.
>
> 73, Jim K9YC
>
>
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-- 
Dave Manuals at ArtekManuals.com www.ArtekManuals.com