Saturday, November 26, 2016

New Feature of the 2Tone RTTY Decoder

The 2Tone RTTY Decoder by G3YYD has been upgraded with a new feature.  This new feature is ON by default and in operation and causes 2Tone for look for strings of repeated characters that are at least 6 RTTY characters surrounded by space characters.  2Tone will then enclose those characters in brackets { } so that it will stand out better when you are looking at the received copy.

Version 3.50.294 of Logger32 contains this improvement:
The latest 2Tone RTTY engine has an auto-correlation feature. Support of this feature is added to the Logger32 2Tone windows.

Here is the description from the latest version of 2Tone about this feature:
This version of 2Tone 16.11a introduces a new function. It is an optional function that is enabled by default. It looks for repeated strings of characters surrounded by space characters and are are at least 6 RTTY characters. 2Tone combines the analogue data of the two strings and displays something like this { G3YYD }. The brackets indicating it is a combined version of the 2 strings with a lower probability of error than the single strings on their own. It is all based on statistics so sometimes there will be false matches. Sometimes the {} will not be correct while one of the strings is.

Extract 2Tone.exe to overwrite your current 2Tone.exe.

In setup menu, there are two new items: Repeat Match and Same Reject on.

Repeat match checked (default) will enable the repeated string matching function.

Same Reject on (default unchecked) when checked will surpress the { } output when both input strings are identical. This saves display clutter.

       [NOTE from W8TN: I found the "Same Reject on" feature was CHECKED by default and I had to change it to get the feature to work.]

Internally 2Tone uses auto-correlation of the analogue data to find probable repeats of information. To eliminate potential false positives, the repeated character strings are identical and surrounded with space chacaters plus being at least 6 RTTY characters.

Sent message like " DAVID DAVID " will work but " ED ED " will not - not enough characters . Nor will " DAVID DAVID, " work due to comma at end. " IO92NQ IO92NQ " will work as will " M7T M7T "

This is the way G3YYD describes the new feature in his announcement to the RTTY Contesting Group:
This new version fixes a few minor items but the big one is it will now look for character strings that are repeated and combine the analogue data together to provide an output that has a lower probability of error. To distinguish this synthetic output from what was actually decoded its output is surrounded by curly {} brackets, e.g. { G3YYD }. Occasionally, it will get the matching wrong and give a false output. It is possible to turn this off see the documentation that comes with the upgrade.
In the recent WAE RTTY contest two stations in the UK found that in 4% of their QSOs that this new system saved asking for a repeat. The normal repeat request rate is 8% of QSOs. A 50% reduction is very worthwhile.
It does however require that the sent information is correctly formatted, which it is in most cases. The format required is for the repeated characters to be at least 6 RTTY characters long and surrounded by space characters. Examples of this are, the quotes are for clarity: " G3YYD G3YYD "  or " DAVID DAVID " or " IO92NQ IO92NQ ". However  " ED ED " will not work too short or " DAVID DAVID, " will not work comma after 2nd DAVID. " M7T M7T " will work as the figure shift, letter shift and a space character make it 6 RTTY characters.
It is not just for contest, it also works for everyday QSOs. Just make sure when sending you name, QTH etc to apply the rules as above when setting up the macros.
73 David G3YYD aka M7T in contests

For Logger32 users:
Bob/K4CY has incorporated this feature in Logger32 with an added twist. Logger32 users can opt to convert the   { G3YYD } to G3YYD  . Right click on the 2Tone decode window and check “Underscore corrections/recommendations.”

Below are a couple of screenshots of how this looks.  It was difficult to find any RTTY signals this morning with the CQWWDX CW Contest running so I had to use a pre-recorded sample RTTY file and a YouTube video to get some RTTY signals.

This first one shows the output of 2Tone recognizing a repeated character string (7L4IOU 7L4IOU) and the auto-correlated output is surrounded by curly { 7L4IOU } brackets.  I can see where this might help you notice the callsign better when there is a lot of text displayed on the screen.  Note that in the line above it auto-correlated (176 176) and printed it as { 176 } to show that it had auto-correlated that text string.  [Click on any image to see it larger.]

 But, in trying to get more samples, I found that 2Tone was making many mistakes in identifying a repeated string.  Many times it would print two calls but then put inside the brackets (or underlined in Logger32) a different callsign.  To me, this could lead to more confusion.

In the above example 2Tone prints (GA7RY VA7RQ) as the two strings but auto-correlates that to (VA7RY) which happens to be the correct callsign.  Then it correctly copies (7L4IOU 7L4IOU) and auto-correlates that to (7L4IOU) correctly but also to (UL4IOU) incorrectly.

I guess I will just have to use this feature in the real world for a bit to see how useful it actually is.  If I find it to not be useful, a simple mouse-click can turn it off.

You can download the latest 2Tone program as a ZIP file here:

For those with Logger32, you need to download the latest version of 2Tone (16.11a) as a ZIP file, extract the contents, and copy the “2Tone.exe” and “2Tone.pdf” files into your Logger32 directory.

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