Re: LF: SlowJT9: 1st QSO and 2nd bug found

[Markus Vester <markusvester@aol.com>]

Hi Rik,

thanks for the great work on this nice piece of software!

Comments / questions from this end:

1. My LF equipment has a fixed 135.5 kHz LO, so audio will need to be around 1800 Hz or so. Such TX and RX frequencies can apparently be be set (albeit red), but the clickable spectrogram range ends hard at 1400 Hz. Would it be possible to allow a user defined spectrogram shift? The alternative is external frequency conversion using SpecLab and virtual cables, but I'd rather avoid that due to extra latencies.

2. In the past I often found myself just missing the start of the next transmit slot (particularly when entering free text). Is it possible to start a transmission a few seconds late into the timeslot, or even change the message on the fly? I think the SNR penalty of loosing a few symbols at the beginning may not be too severe.

3. The software seems to be fairly stable. Clicking the "save any work done on this computer" disclamer may not be necessary on every startup.

Best 73,
Markus (DF6NM)



-----Ursprüngliche Mitteilung-----
Von: Rik Strobbe <rik.strobbe@kuleuven.be>
An: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>; rsgb_lf_group@yahoogroups.co.uk <rsgb_lf_group@yahoogroups.co.uk>
Verschickt: Fr, 9. Nov. 2018 23:27
Betreff:  LF: SlowJT9: 1st QSO and 2nd bug found

Dear all,

I just completed a JT9-2 QSO with Marco, DD7PC:

2141 -11  0.1 1104 2  OR7T DD7PC JN49       
2145 -10  0.1 1106 2  OR7T DD7PC JN49       
2153 -16  0.0 1105 2  OR7T DD7PC R-13       
2157 -12  0.0 1105 2  OR7T DD7PC 73         
2201 -16  0.1 1106 2  UFB RIK

During this QSO I discovered a 2nd bug: 

As can be seen above the time (UTC) is given at odd minutes (eg. Marco's 21:40 - 21-42 transmission is reported 2141). This because the time is taken at the moment of decode. 

For JT9(-1) this is not an issue, because decoding is in the same minute as the start of transmission, but for JT9-2 and JT9-5 it is because it results in a wrong calculation of the cycle (1st or 2nd). As the wrong cycle is given SlowJT9 will transmit in at the same cycle as the station you received, very inconvenient!

I will fix this big after the weekend (sorry, to many other obligations on Saturday and Sunday).

For the time being the workaround is rather easy: if you get a decode you want to reply to (by double clicking on the call) just change the cycle manually (click once on the "TX 1st cycle" checkbox). The good thing is you have plenty of time to do so as there are 20 seconds between the end of a transmission and the start of the next cycle. 

To end with a positive note: during Marco's 2152-2154 transmission there was very deep QSB and his signal dissapeared from the waterfall display for almost 1 minute. But despite that still a good decode, just some dB weaker.

73, Rik  ON7YD - OR7T