DK8KW Longwave Information
Calibration of my Receiving Antenna in dBµV/m

Basic Calibration to convert dBu or dBm readings taken with my receiving equipment into dBµV/m:

Following some instructions given by Dick, PA0SE, I have made a 1 m Diameter loop (for deteils see below) from a solid copper pipe and took some very basic measurements. The comparison of taking the measurments in my shack or out in the fields is marginal.

Hen, DF3OE with the loop

I measured the voltage of DCF39 to be -86.9 dBu which is equivalent to a voltage of 35 µV
(0 dBu=0.77V, so -86.9 dBu=20*log(35µV/0.775V)).

From the equation (valid for 137 kHz):

    I derive
  equivalent to
  (83.7 dBµV=20*log(15 mV/1 µV)).

At the same time the signal strength of DCF39 with my regular 18m high umbrella antenna was

This value equals to

So the correction factor for my antenna system for dBm can be calculated as follows:
    and for dBu as follows:

For my antenna system and the signal strength given in dBu, add 108.1 dB to achieve values in dBµV/m.

Details of my solid loop
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