DK8KW Longwave Information
Field Strength Profile of Burg, DCF39

On April 8, 2000, Gamal  he and myself took a nice ride to the Burg transmitter facility, took some pictures and a field strength profile
from the location back to my home QTH, approximately 120 km away.

As DCF39 is one of the few LF signals that has been heard on the other side of the atlantic, it might be interesting for further field strength
calculations to know the ERP. With our measurements with an untuned 1m-diameter loop and a calibrated level meter (MV61, as my Siemens D2108 gave up its work) we came to the result, that the 50 kW DCF39 signal on 138.830 kHz mark frequency is being transmitted from a 325m high antenna. The actual ERP we came up with (matching the appropriate CCIR-curves with a very good correlation) is

40 kW ERP (see below).
So for all you guys in Canada or the U.S. that are able to hear DCF39, you might consider this ERP in relation to an amateur signal of only 1 W ERP (but maybe 1000 km closer to you location if it is a UK or Irish station).
The 40 kW estimation is based on calculations made by Veino (OH2LX) and also on the curves derived from the CCIR- RECOMMENDATION 368-7 named "GROUND-WAVE PROPAGATION CURVES FOR FREQUENCIES BETWEEN 10 kHz AND 30 MHz". The recommendation contains curves from 30 kHz to 30 MHz, based on various conductivity values. As no 136 kHz is available, we have selected the 150 kHz curve instead. The curve shows the expected field strength for a 1 kW signal vs. distance.
The conductivity can be derived from the following map. The area we used for our measurments has an average conductivity of approx 6 mS/m.
Courtesy of Telefunken Sendertechnik Berlin

Please send comments & suggestions to:  

copyright (c) 2001-2006 by dk8kw, all rights reversed