Topband: Short radials?

[DAVID CUTHBERT]

Tom, with this ground system and 90 degee monopoles I measure 5 ohms ground
loss on 7 to 28 MHz. With the 30' vertical I measure about 10 ohms on 1.8
and 3.5 MHz.

The 7 MHz measurement agrees with the N6LF papers (90 deg monopole and 1/8
wavelength radials).

I have no evidence that would lead me to  doubt the measurements of the
other bands.

160 meters measurenent:
15 ohm base R
2 ohm radiation resistance
5 ohm cool loss
8 ohm ground loss (rounded to 10)

This is the accepted procedure for measuring base referred ground loss, is
it not?

Dave WX7G
On Sep 27, 2012 7:54 PM, "Tom W8JI" <w8ji at w8ji.com> wrote:

> I am presently using a 30' base loaded vertical. The ground system consists
>> of 90 radials from 12 to 25 feet. The base referred ground loss is 10
>> ohms.
>>
>
> The problem is we really can't measure ground loss at the base.
>
> Let me give an example....
>
> A 40 meter vertical here, 1/4 wave tall of fixed length.
>
> Four elevated radials had less than 40 ohms feed resistance. About a dozen
> buried radials had around 60 ohms base resistance.
>
> Field strength was identical despite the resistance difference with the
> same length resonant radiator.
>
> Others have measured the same type of thing, and it is easy to duplicate
> results like this.
>
> 73 Tom
>
>