locked JT9-Fast Tone spacings #JT9


Andy Talbot
 

I've been silly
I programmed my real time locator beacon source using JT4G-Fast via QO-100
for the tone spacing specified for JT4G, viz. 111.1Hz. For the fast mode
this was wrong. It needs to be equal to the baud rate, 100Hz tone spacing.

What is amazing is that is worked at all, albeit only decoding a small
fraction of transmissions. On my mobile tests I originally put this down
to satellite reduced gain, and shading by foliage. Tests using a fixed
message a couple of months earlier *did* have the correct tone spacing.

RSGB members will see the test results in the next RadCom due in a couple
of weeks. Now I need to run the mobile test again, with the proper tone
spacing.


Andy
www.g4jnt.com