Hi Peter and group,
If you are close enough to receive surface wave from DCF39 and surface
wave from Sylt, then a ratio of the DCF39 carrier level to the level
of a typical Sylt LORAN line (at midday) could be used to give the
emrp of the LORAN line. WE can estimate the path loss from the
distance within a few dB so long as the both paths are over similar
type of ground.
But Dave G0MRF also sent me a nice spreadsheet of some measurements
which were made at Rugby when the LORAN transmitter was installed.
This is a record of the classic USCG measurement to confirm that only
1% of the energy is outside 90-110kHz. This spreadsheet seems to be a
chart of the readings of a spectrum analyser which is changed in 2kHz
steps between 70 and 130kHz, measuring the levels in a narrow
bandwidth (<2kHz?) from an antenna-current monitoring point.
I think Dave's "extrapolated" chart will give more reliable data than
this "relative" measurement described in my previous message:
I live 230 km away from Burg, and 300 km from Sylt. Now I found this:
Turning the receiver's AGC off (to get a meaningful result from the
audio amplitude), and setting the gain manually so DCF39 just doesn't
overload it, I can hardly see the Loran signals on 137.x kHz / QRSS3
mode. The dynamic range is not sufficient for this test. I guess a
transmission from an amateur station with well-known radiated power
(possibly close to a Loran site) would be better suited.