Topband: Monopole Radiation Patterns, takeoff angles etc

[Richard Fry]

Guy Olinger wrote:

>BL&E gave their study conductivity limits as between 20 and 100 
>milli-Siemens !!!

Those who believe so might want to review the conversion from the e.m.u. 
units used for earth conductivity in the BL&E publication to the mS/m units 
more commonly used today.

--> The conductivity values used by BL&E as quoted above are overstated by a 
factor of ten. <--

Other details that may have been overlooked or forgotten:

- The BL&E tests were conducted in the sandy soil of New Jersey, where 
according the FCC M3 chart of earth conductivities, that state ranges from 2 
mS/m to 4 mS/m.

- Field intensities were measured by BL&E at a distance of 3/10 of mile from 
the radiator, and mathematically converted to an equivalent IDF at 1 mile.

- The test frequency was 3 MHz.

- Even with such rather low earth conductivity at/near the BL&E test site, 
the fields they measured for monopoles of ~45 degrees and more, using 113 x 
0.412-wave buried radials were within several percent of the maximum fields 
possible for the applied power when using perfect monopoles of those heights 
driven against a perfect (zero loss) ground plane.