Topband: Skywaves from Monopole Surface Waves

Richard Fry rfry at adams.net
Sun Oct 7 16:37:52 EDT 2012


Guy Olinger wrote:

>** What was the station and location?  This allows us to view the location 
>ourselves with Goggle Earth and other tools. etc etc etc

The data I posted was sent to me as a courtesy by the consulting engineer 
who measured and compiled it.  He performed these measurements as a paid 
service, for submission to the FCC.  Revealing the requested details would 
not be not appropriate or fair to the client who paid for them.

I will respond to a few of Guy's comments, although most of this could have 
been learned by a more careful reading and consideration of what I posted.

As I stated in my post, the measurements were made at a distance of 2.8 km 
from the radiator.  That distance is 5 wavelengths from a MW broadcast 
monopole on 540 kHz, and almost 16 wavelengths at 1700 kHz.

At a distance of 2.8 km, the elevation range over which the measurements 
were made was zero to 3 degrees (as posted).  It would be the same 
regardless of the height of the monopole.

As I posted, the path length is so short that earth conductivity will have 
little affect on the measurements.  That is why a short path length was used 
for these measurements.

This consultant has made helicopter measurements of 4-5 other MW stations, 
but I would not expect them to show anything different in principle than 
what I already posted.

The measured fields by the consultant show that no "notch" exists in the 
elevation pattern of that monopole from 0-3 degrees.  Nor would one appear 
in the elevation pattern of ANY monopole up to 5/8-wave in height. 



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