[600MRG] LF: SlowJT9 update (v0.9.10): tuning issue solved

[N1BUG]

Hello Rik, all,

Yesterday I could do some tests with my QRP Labs U3S transmitting,
SlowJT9 receiving. I used a lot of attenuation between U3S and TX
antenna. Then there is another 30 or 40 dB lost between the TX
antenna and RX antenna. The result was that in JT9-1 I had a signal
which was most of the time -27, occasionally -26 or -28.

I then switched to JT9-2. I confirm SlowJT9 will decode these
transmissions using the old baud rate. SNR was now mostly -29, so I
am not sure this is reporting correctly. SNR should have remained
the same when changing modes.

I then switched to JT9-5. I confirm SlowJT9 will decode this OK. SNR
was now mostly -30, again does not seem logical to me.

More tests are needed to see if I always get the same SNR results on
the different modes! There was not enough time to run enough cycles
of each mode to eliminate random chance.

I tried JT9-10 but I could not get any decode. I assume for this
mode the audio frequency must be under 500 Hz? I tried 470 Hz but
nothing. The signal was clearly visible on the waterfall but did not
decode.

Later, K3MF upgraded to the new version and made some JT9-2
transmissions on 2200m. His signal was strong as usual, but I could
not decode him at all. I could confirm that his transmission was
occupying the correct amount of time for the slower baud rate, but
it could be decoded.

That is all for now. I will continue my SNR tests between the submodes.

73,
Paul N1BUG