moderated #JT4 Worrying comment for beacon users #JT4


Andy TALBOT
 

In an email I received today, someone made the comment 

"the earlier JT4 (which has unfortunately been declared 'obsolete' and removed from the latest release candidate), JT65 and QRA64 (also removed..."

I'm hoping above all else this was just a mistake on the writer's part and that JT4 and JT65 will always remain, even if they are less efficient than the others   They have been implemented on a large number of beacons around the World now and it would be catastrophic if the modes were removed from the WSJt-X suite, and users required to keep an older copy in parallel with the latest.  AFAIK, it's only QRA64 that has gone, to be replaced with Q65.

As far as I can see, JT4G is still the only mode that can cope with the really wide spread of rain scatter on 10GHz and 24GHz.
I'm also hoping JT9 stays, too.   Like JT4 its implementation in a small processor, encoding in real time is straightforward, unlike the memory-heavy matrix-encoder later modes.

It really would be a great pity if beacons were forced into using the rather cut-down PI4 mode because of a fear of built in obsolescence on any of those in WSJT-X.  PI4 itself, being inspired by and generated the same way as JT4G
 

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Joe
 

Hi Andy,

You say someone told you

"the earlier JT4 (which has unfortunately been declared 'obsolete' and removed from the latest release candidate), JT65 and QRA64 (also removed..."

... but you don't identify the source.  Certainly the comment did not come from the WSJT Development Team.  We have no plan to retire either JT4 or JT65.

While I think of it: The wider Q65 submodes work very well on 10 GHz rainscatter.  An example is included in the sample files downloadable from the WSJT-X Help menu.

  -- 73, Joe, K1JT


Mike Lavelle K6ML
 

Joe & Andy,

Sorry, that was my mistake.   I mixed up ISCAT (which is unfortunately being deleted... it’s still being used for microwave aircraft scatter) with JT4 (which is alive and well).    In the last part quoted, I was not writing that JT64 was retired, just QRA64 (the parens only applied to QRA64).  The discussion after the ellipsis was about which modes used hard keying vs Gaussian keying.

Mike K6ML

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------ Original Message ------

From: Joe
To: main@WSJTX.groups.io
Sent: March 17, 2021 at 6:43 AM
Subject: Re: [WSJTX] #JT4 Worrying comment for beacon users

Hi Andy,

You say someone told you

"the earlier JT4 (which has unfortunately been declared 'obsolete' and removed from the latest release candidate), JT65 and QRA64 (also removed..."

... but you don't identify the source.  Certainly the comment did not come from the WSJT Development Team.  We have no plan to retire either JT4 or JT65.

While I think of it: The wider Q65 submodes work very well on 10 GHz rainscatter.  An example is included in the sample files downloadable from the WSJT-X Help menu.

  -- 73, Joe, K1JT


Andy TALBOT
 

Excellent news
All sorted
SRI for raising the point


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Joe
 

Hi Mike,

I think I mentioned before that we never received any comments or feedback about ISCAT being used for aircraft scatter in your area. 

I strongly encourage you to try Q65-15B or Q65-15C for this purpose, and to report back on your results, including recorded .wav files.

  -- 73, Joe, K1JT