Many thanks to Alan Melia G3NYK and John VE1FTL for the
valuable details on canadian station CFH.
Antenna systems designed for the frequency range around 150 kHz,
composed of vertical mast 200-360m in height, capacitive toploading,
radial system 60 to 120 radials (each having a length which is equal
to the mast height) reach a typical over-all system efficiency of no less
than 80% and no more than 95%, 90% being the most common
design target value (for no compromise implementation).
example-1 (Donebach LW BC station on 153 kHz):
double 360m mast + cap-top
transmitter power = 500 kW (27.99 dBkW)
EMRP = 794.3 kW (29 dBkW)
antenna efficiency = 88%
antenna directivity (**) = 1.805 (2.565 dB)
antenna gain (**) = 1.589 (2.01 dB)
(**) = relative to lossless monopole over perfect ground plane
In compromise implementations and for lower operating frequencies,
system efficiency degrade rapidly.
example-2 (Mainflingen standard time and frequency station on 77.5 kHz):
single 200m mast + cap-top
transmitter power = 50 kW (17.99 dBkW)
EMRP = 30 kW (14.77 dBkW)
antenna efficiency = 60%
antenna directivity (**) = 1 (0 dB)
antenna gain (**) = 0.6 (-2.218 dB)
Best 73 de Gamal
Gamal Soegiono (SWL)
50N01 / 08E27 / JO 40 fa
[email protected]
or
[email protected]
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