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Dear Dick and All,
about DLF. During daylight time normal
transmitting power is 500KW from 2 transmitters by Telefunken, each 250KW. These
power is fed to the northwestern one of the two masts. The southeastern one is
coupled by radiation and has a phase shift. This generates a 3dB attenuation to
southeast - because of Radio Brasov, Romania, on the same frequency. During the
night power is reduced to 250KW, fed to both masts, also with phase shift. So
the attenuation increases to 11dB to protect the Brasov-area. I think you get
the full radiation. But probably today is only one transmitter in use because of
maintenance. Please try next week again. BTW: The carrier is also modulated in
phase shift with GPS-correction-data.
73 Walter DJ2LF
-----Ursprüngliche Nachricht-----
Gesendet: Samstag, 27. Juli 2002
11:03
Betreff: LF: Power of Donebach 153kHz
TX
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
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