[HCDX] Groundwave Propagation On SW -- rule of thumb is 300 km on SW

["mhev" <mhev@xxxxxxxxxxx>]

The general rule of thumb is 300 kms per hop for 5 - 20 mhz, as I understand
it.
VOAarea, ICEarea, and REC533 programs basically agree with me, but these are
skywave numbers.

SW (using groundwave) is almost like AM / MW to a point, with dipoles.
Vertical Dipoles (ground screen or not) seem to, as you go higher in
frequency, have launch angles that begin to approach the horizon. Still,
except for several EU nations that have used dipoles for European service --
dipoles are not commonly used on SW.


----- Original Message -----
From: "Thomas Giella KN4LF" <kn4lf@xxxxxxxxxxxxxxx>
Subject: [HCDX] Groundwave Propagation On SW


  Groundwave propagation distance is definitely dependent upon transmitter
power, transmission mode, vertical antenna design and ground conductivity.
Horizontal antennas produce virtually no ground or surface wave broadside to
the antenna but they do produce some off of the ends.
  [ ...]
   You might expect to see the following approximate ground or surface wave
distances for given frequencies:

350 kc 400 miles
540 kc 200 miles
1800 kc 100 miles
3000 kc 60 miles
7000 kc 40 miles
28000 kc 10 miles

Over water is a totally different story. At day on the beach at Cape
Canaveral, FL you can here the MF AM broadcast band 50 KW stations in New
York City at an approximate distance of 1000 miles.


73,
Thomas F. Giella
Space & Atmospheric Weather Forecaster




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