LF: Power of Donebach 153kHz TX

["Dick Rollema" <d.w.rollema@freeler.nl>]

To All from PA0SE,

Sorry to bother you again with a field strength story. But the delete key
is within easy reach...

The Deutschlandfunk Donebach transmitter at 153kHz is on again. At 0840
UTC today I measured its field strength as 5.6millivolt/metre.
Using the CCIR groundwave propagation curve that produces plausible
results on DCF39 and M0BMU the Effective Monopole Radiated Power (EMRP)
comes out as 157kW.

On the Internet I found transmitter power is 500kW. But there are two
363m high aerial masts. This suggests a directive array. As the
transmissions are probably not meant for the Netherlands we may get only
part of the full blast.

Measuring with the SPM-12 in 25Hz bandwidth the reading moved up and down
a bit with the modulation. Perhaps some power (and money) saving
controlled carrier system is used. It could also be that some of the
lowest modulation frequency components are passed by the 25Hz  I.F.
filter. But other BC stations on LF do not show the effect. 

73, Dick, PA0SE