"Reg Edwards" wrote in message
...
I have lost all previous contributions to this thread.

But Jimmie gave the description of his radial system -

12 12f t wires, Center ground stake 10 ft long, far end of each wire
has
a
stake about 3 ft long. These are used more to just hold the wires in
place.

plus a brief description of type of soil and moisture content. I guessed
at
wire diameters.

From which I deduce the following input impedances -

AT 1.9 MHz AT 7.0 MHz
---------------- ----------------
10 + j0 13 + j11 ohms.

Uncertainty = +/- 3 ohms which is adequate for the intended purpose.

The above figures have been obtained using programs ENDFEED and RADIALS2
(two different modelling methods) and averaging the results at soil
resistivities of 100 and 300 ohm metres. Programs can be downloaded in a
few seconds from website below. Calculating time no longer than needed to
enter the simple data.

In practice, only the resistances matter because the reactances are tuned
out simultaneously with the antenna, equivalent to minor readjustments of
the tuner. The resistance values, in conjunction with calculated
radiation
resistance can be used to calculate radiating efficiency.

If Jimmie should ever measure input resistance with similar uncertainty
(not
too difficult) then I should be pleased to hear his results.

I had really not given it a whole lot of thought unti gettin invovled in
this thread but I am beginning to think that my sort of unique soil
conditions may effect my ground system considerably. With the moist, top
soil and clay at the lower levels I am getting a good primary power ground,
but now I dont think my RF connection to earth is very good at all ass the
counter poise is in some fairly dry sandy clay. Wife says that when I
installed this thing back in '94 that she remembered me putting in some
longer wires than the 12 12 ft wires. At this point I am thinking maybe is
was 8 12 ft wires and 4 1/4 wl 20m wires. I know the origonal plan waas to
put in the 12 ft wires and 1/4 wl wires for several bands out to 80m with 3
or 4 wires for each band. I know I didnt do it for 80M but now I must admit
I am not sure about other bands. I may have put in other radials for 20 and
40 meters. Shortly after this I almost totally gave up radio until
recently.