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FT8 and splatter

KF4VAR
 

I discovered this article and found it interesting---G4DBN  used an FDM Duo  for testing....thought I would share this...

http://www.g4dbn.uk/?p=783

Regards & 73
Carr KF4VAR

Neil Smith G4DBN
 

That post needs an update.  Since 2.1, the FT8 tones are generated using  a Gaussian frequency shift keying, so the sidebands no longer look like that.  The skirts of the specrum are hugely improved.  I gave a lecture at the 2018 RSGB Convention and then the same talk had an urgent reprise at the 2019 Convention when another speaker was taken ill, but I didn't have time to update those slides.  The improvement is HUGE.

Of course it should never have been released with abrupt changes of frequency in the first place, but now it uses GFSK, the bandwidth usage is so much better.

Neil G4DBN

On 14/11/2019 21:31, KF4VAR wrote:
I discovered this article and found it interesting---G4DBN  used an FDM Duo  for testing....thought I would share this...

http://www.g4dbn.uk/?p=783

Regards & 73
Carr KF4VAR></a>

KF4VAR
 

Neil
Many thanks for the additional information.  I am in total awe  that I posted an earlier version of your article...... Given that I sold my station in 2012  and am still trying to get an FDM Duo to Ecuador (have not operated since 2012)  your information is much appreciated. Didnt know about the change. I am going to guess that you were a contributor  to the bandwidth improvement, no?

Many kind thanks again, I am getting an education. What a great forum and users group this is!

Regards & 73
Carr KF4VAR