From G3PLX:
When Rugby LORAN failed to shut down last Tuesday, it occured to me that I
could adapt my coherent locking program to measure the LORAN SNR even while
LORAN was transmitting. I measured -5dB, that is, LORAN (from Rugby) is 5dB
below the noise level (without LORAN). G3NYK also tried it and gets -2dB. He
is closer to Rugby than I am.
This morning I noticed that Rugby LORAN went off between 10:15 and 10:45
utc, and during that gap I measured the noise level, and again when it came
back on. The difference was 1.2dB, which agrees with the above measurement
of the LORAN and the noise separately.
I am not sure that it would be easy to do a large-scale survey of LORAN
noise levels with my program because it's not easy to set up, and there will
be a large variation in the noise levels at different locations, but if
anyone would like to experiment with the program I wrote to do it, contact
me off the reflector. It needs an ordinary PC with a good quality soundcard,
and a 136kHz receiver with good frequency stability.
73
Peter
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