Stefan,
I you could measure the power delivered by the earth antenna to a correct load
you would be able to calculate the efficiency of the antenna (knowing distance
to and ERP of DLF)
73, Rik ON7YD
________________________________________
Van: [email protected] [[email protected]]
namens Stefan Schäfer [[email protected]]
Verzonden: vrijdag 9 juli 2010 0:26
Aan: [email protected]
Onderwerp: LF: DLF passive received with earth antenna
Roger, LF,
Just forgotten to mention: Today i tried just for fun if it is possible
to make the Deutschlandfunk DLF / 153 kHz audible in a car speaker (4
Ohm) without any additional energy sources and using my 300m earth
antenna that is fixed installed on the hill.
It is possible! The level is not too loud but you clearly can understand
all what they say when holding the speaker in a distance of 0,5m to the
ear. I just used a bridge rectifier out of 4x BAT47 diodes and a 10nF C,
that's all ;-)
There was not really a difference when using a 1:4 audio transformer (4
Ohm on low impedance side).
Currently the R-loss of the earth antenna is 1 kOhm although it was 650
Ohm in the last TX test. Probably this is due to the heat...
Maybe it has to be mentioned that DLF transmitts 500 kW and is in a
distance of 40 km to that QTH ;-)
73, Stefan
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