> When monitoring JT65A I decoded > CQ N4WO EL88 1 and 0 > What is the 1 and zero? > Also what is the meaning of the # and * I see in the decoded lines? > Dan
Hi Dan and fellow JT65 fans You ask a very good question as understanding the meaning of these symbols is at the heart of digging deep into the noise to work the DX. Here's an example decoded sequence for reference: time sync Db DT DF W 002400 6 -23 2.5 223 23 * CQ VE7TIL CN89 1 0 The first few indicators WSJT provides labels and are easy to understand. The * and # indicate whether the message is a call type message like the CQ above or something like DX1AA VE7TIL CN89... Now if DX1AA responds to me with VE7TIL DX1AA FB00 OOO then his message will be decoded with the mysterious # indicated. The # tells you the sync is reversed to indicate OOO! If you get a good sync on a message but not enough signal to decode it then you can still tell what your QSO partner is trying to send and know to keep trying! This is critical on EME where everything is marginal. Pay close attention the next time you're on the air and you'll see this in action and all will be self evident... The 1 and 0 indicate 'which' decoder has decoded the message and as we'll see how confident the decoder is it got a good decode. The 1 above indicates the Reed Soloman decoder decoded the message and is 100% sure of its contents. Now if the message was corrupted by noise and QSB then you may see something like: 002400 6 -29 2.5 223 23 * CQ VE7TIL CN89 0 5 Note the Db level... The above indicates the the Reed Soloman decoder failed (the first number changed to 0) and that the DEEP SEARCH decoder has a 50% (the range is given from 0-10) certainly the message was copied correctly. In practice and my experience, if you see this then the message is almost certainly correct. Infact, a ? will start to appear at really low confidence levels to indicate to the operator to suspect the decode and attempt another before accepting it. OR let it average up to a positive Reed Soloman decode over a few sequences. The deep search decoder works by taking the callsign AND grid in the user input boxes on the left lower side of the screen and comparing the received data with that of the call3.txt database on your hard drive. If there is a match a result like above is displayed and a confidence level given. Therefore, you must actively maintain your call3.txt file and use the Radio to: and Grid: boxes... Having gone this far lets talk about the average decoder... You'll have likely noticed the 'little' window below the main decoder window. This is the average window. There are two rows for 1st and 2nd period decodes to average up if you take my meaning. Each time a sequence is decoded and if there was enough of a sync as set by the user, the message will be added to the average buffer. If you manage the buffer (using clear aveage, include and exclude) actively you can pull VERY weak signals out of the ether that would have never been decoded on a single decode try and some may not be even visible on the waterfall!!! I have worked many an EME single yagi station using this technique. This is also where the # sign comes into practical use again. If you decode this in the average window and nothing in the normal window: 002400 1 7/10 VE7TIL DX1AA FB00 1 0 Now look closely in the normal decode window and see if there is a # in the normal decode window then you know he's sending OOO your report and has copied both calls!!! There could be no decoded text in the normal window so understanding this is giving you a great advantage during weak signal trys! Finally the 7/10 in the average example above indicates that 10 seq where averaged and only 7 where meet the required sync level to be included in the average buffer. Again actively managing the average buffers is critical to working the weak ones... I hope this answers your question Dan and you get so practical use out of this :-) 73 Scott VE7TIL CN89lg PS - I hope everyone sees that JT65 is not as automated as it first appears, it really does require a skilled operator who understands the software's capabilities and has the insight and skill to use them.
