Topband: I need help proofing an Inverted L model I made please. 40’ x 143’, four 100’ radials, #14 wire.

[Grant Saviers]

Rudy Severns has many plots of elevated radial numbers, lengths, and 
elevations on his web site  antennasbyn6lf.com

My "T" showed the expected change in feedpoint Z as I added 125ft long 
10ft elevated radials from 2 to the current 8.  The last two made no 
measurable difference.  From Rudy's analysis they could/should be a bit 
shorter than 125ft.

Another experiment with a prototype shorty vertical showed a big 
reduction in Z when two 128' radials were raised from 4ft to 9ft, 
confirming the NEC4 modeling.

Poor dirt here but a little bit better in winter when the ground is 
totally water saturated. Also, the T is pretty much surrounded with 
100ft plus firs and cedars absorbing RF.  Another reason to love 
verticals on the beach :) .

Grant KZ1W

On 12/11/2020 02:02, Artek Manuals wrote:
> Jim et all
> 
> I agree with what you say on all points when it comes to radials on the 
> ground and salt water affects.
> 
> However I have always wondered about elevated radials . The NEC ( both 2 
> and 4) models (not that those are to always be trusted) show very little 
> (if any) improvement beyond four elevated radials, you have any theories 
> on why that is? Intuitively (also not to be trusted) that is a lot of 
> real estate in the spaces between
> 
> Dave
> NR1DX
> 
> On 12/11/2020 4:37 AM, Jim Brown wrote:
>> On 12/10/2020 11:14 PM, Raymond Benny wrote:
>>> With said, I believe my ground absorption is very high so I feel the 
>>> higher
>>> numbers of radials helps greatly with my vertical efficiency and 
>>> radiation.
>>
>> Hi Ray,
>>
>> The soil affects us in two important ways. First, poor soil burns 
>> transmitter power underneath the antenna and it's near field. We use 
>> radials to shield the soil from the field, and to supply a low 
>> impedance path for return current. Magnetic fields produced around 
>> each radial by virtue of current flow couples loss in the earth into 
>> the radials in the form of series resistance. Loss in each radial is 1 
>> squared R; each time we double the number of radials the current in 
>> each is divided by two, so the power coupled to the earth by each 
>> divides by four. So the more radials, the less power is coupled to the 
>> earth. THAT'S why more is better. The result of all this is that loss 
>> in the soil under the antenna reduces the total strength of our signal 
>> by that amount.
>>
>> The second effect of soil is in the far field, where we field radiate 
>> hits the earth and is reflected by it to form the vertical pattern. 
>> The better the conductivity THERE, the our pattern will be both 
>> stronger and at a lower angle. An antenna with its base just above sea 
>> water is the extreme example of this -- the reflection is extremely 
>> strong, and it is at a VERY low angle.
>>
>> We can help the first of these two effects with a good radial system, 
>> but the only thing we can do about the second (the far field 
>> reflection), is to move where there is better soil. Most of us live 
>> where we do because we like living there for reasons other than radio. 
>> And that includes me and my XYL.
>>
>> 73, Jim K9YC
>>
>> _________________
>> Searchable Archives: http://www.contesting.com/_topband - Topband 
>> Reflector
>