Peter Martinez wrote:
John:
By all means quote my explanation, but it's not an explanation which
should be attributed to me, since the reason behind it has been known
since LORAN began. It only applies to LORAN transmitters like Lessay
and Sylt which are 'dual rated', that is, which have two distinct
pulse repetition rates. Rugby and Soustons (SW France), for example,
don't gallop.
The term 'Galloping Horses' has also been around for a while. UK
stations were certainly using it in 1998 when the LORAN problem first
reared it's ugly head on 136kHz.
I think I may have coined the term. During the early days of listening
for test transmissions from G4JNT on 73kHz around the summer of 1997 I
was using a loop antenna. I found that I received this strange galloping
signal when the loop was orientated for maximum to the south. I put out
an e-mail on the reflector asking what this strange signal was
(describing it as sounding like Galloping Horses) and G3JKV responded
informing me that the signal was from the Loran station at Lessay on 100kHz.
The Loran interference was not that bad on 73kHz but was a lot worse
when we went to 136kHz. It would hold the S meter at S7 at 2.5kHz IF
bandwidth.
Peter, G3LDO
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