John G4CNN,

Regarding your comments:

One thing has become very clear, this sort of experiment requires good

preparation, and a familiarity with the very small bit of the band that one
is monitoring, which at 120 second dots is only 1.3 Hz wide and includes no
Loran lines. So you either need a very accurate frequency standard or have
got to know what is where on the band.

ZL6QH will be having another all night transmission on 15 December.  We do
not want to compete with any known QRM, so I am open to suggestions as to
selection of optimum test frequencies.  Also I can arrange for FSK down to
0.1 Hz but I did not change from what was first notified by bulletin as it
could have caused confusion with self-analysis of what was captured.

The recently arranged loading coil at ZL6QH is light on inductance, so I
will provisionally say that any new frequency needs to be within 500 Hz of
the upper band edge.  The frequencies can be set to "anything" as I use
computer generated tones (VFSKCW software developed by Steve VK2ZTO) and an
SSB exciter directly at LF (modified TS-850SAT for LF tx, and with a very
good TCXO).

I have not seen Loran lines down this way, so I do not know what spacing
they have, but it strikes me that the ZL6QH frequency shift should be
arranged to have a "half spacing" relationship with Loran lines, so even if
one ZL6QH tone is covered by QRM, the other would be as clear as it could be
(for Argo display).

So I'm open to suggestions on centre frequency and frequency shift for the
next test from ZL6QH on 15 December.

73, Bob