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Hello Jim, all,
my plan was that SlowJT9 will decode all JT9 submodes and show them on the same decoder window. The user can see for each decoding what the submode is (the M parameter in the decoder window will show 1, 2 or 5). If the user double-clicks on any call, SlowJT9
will change the TX submode to that of the received station (you double-clicked on) and you are ready for a QSO.
No hastle with 2 or 3 instances ...
But, as said before, this might be difficult with the initial JT9-2 and JT9-5 transmission durations (49 sec for JT9-1, 109 sec for JT9-2 and 290 sec for JT9-5) decoding for all submodes will happen at (almost) the same moment. On a moderate PC during the
a single JT9 decoding the CPU usage peaks to 40-50%. What will happen if 3 instances of the JT9 decoder are invoced at the same time?
An alternative would be to decode the 3 submodes one by one (in series). But I noticed that on a busy band one JT9 decoding can take several seconds, so 3 decodings can take so much time that it exceeds the 10 seconds "response time" (between the end of
transmission an start of the next cycle), preventing the user from responding in time.
With the current JT9-2 and JT9-5 transmission times in SlowJT9 (49 sec for JT9-1, 98 sec for JT9-2 and 245 sec for JT9-5) there is alway at least 10 seconds difference between any (JT9-1, JT9-2 or JT9-5) decoding, what should be no problem unless a very
slow PC is used.
So at this moment I am seeking advice about how to proceed. My aim to to create a tool that is useful for DX communication on 472kHz and 136kHz, so "your wish is my command" (but keep it realistic).
73, Rik ON7YD - OR7T
Rik, all,
So, as I understand it, on some ordinary night a MF station would/could run at least two software instances of JT9—one instance set to decode 2 minute slow JT9, and the other instance decoding 1 minute JT9 concurrently.
The 1st
s/w instance is set for slow JT9. If the station you want to call or have respond to a CQ is low-SNR like a QRP, transcontinental, or transoceanic station, then you activate your transmission using the slow JT9
software instance. If low-SNR stations comprise the only intended reception, then slow JT9 is all you use and forget the 2nd s/w instance.
You get deep-SNR receptions and QSOs that regular JT9 can’t deliver.
The 2nd s/w instance is set for regular JT9. Suppose the station you want to call or have respond to
a CQ is likely above, say, the 50% decode probability, at least SNR -27 dB most of the time. Then you activate your transmission on-the-fly instead with regular JT9 using that 2nd s/w instance.
That way, you either get a reply after 1 minute or have the chance to repeat your transmission.
The nimble operator uses the 1st
or 2nd s/w instance that’s simultaneously running as conditions and as sought-after stations warrant.
No need to change TX frequency. The DX may be on some other frequency than you, but that’s fine.
You call them with slow JT9 or regular JT9 as you decide on-the-fly without changing your frequency and they will see you on their PC display if they can.
Other stations may be running either slow JT9 or regular JT9 at any given time, and that’s fine too because you
can receive them either way. You’ll see stations TXing slow JT9 on one decoder window and stations TXing regular JT9 on the other decoder window. If a station sends slow JT9 for a while and then regular JT9 for a while, you’ll see that
station go from one decoder window to the other.
If a station is already running regular JT9 diversity with two RX antennas and two regular JT9 decoders connected
to SDR sub-RXs, you just add two more decoders for slow JT9 diversity as well. Depending on your PC, use a PC powerful enough to run the s/w instances concurrently.
Feel free to clarify if I’m missing anything important.
Very interesting! 73, Jim H
W5EST
-----Original Message-----
From: Rik Strobbe < [email protected]>
To: rsgb_lf_group < [email protected]>; rsgb_lf_group < [email protected]>
Sent: Mon, Nov 12, 2018 4:05 pm
Subject: Re: LF: SlowJT9 v0.9.02
Hi Paul, it seems that we will have to make a choice: - either the old JT9-2 and JT9-5 standard and only decoding one mode at a time - or keeping the current JT9-2 and JT9-5 parameters and keep the option open to decode all JT9 submodes simultanious. I tend
to go for the second option, but everyone is welcome to convince me otherwise. 73, Rik ON7YD - OR7T ________________________________________ Van: owner- [email protected] <owner- [email protected]>
namens N1BUG < [email protected]> Verzonden: maandag 12 november 2018 22:43 Aan:
[email protected];
[email protected] Onderwerp: Re: LF: SlowJT9 v0.9.02 I can confirm something similar. My CPU is running around 30% (it's a VERY busy system with many apps running). When SlowJT9
invokes the decoder I see a short spike to 50%, sometimes as high as 55%. 73, Paul N1BUG On 11/12/18 4:13 PM, Rik Strobbe wrote: > I just had a look at the CPU usage of my computer: > it is wobbeling between 2% and 5% but peaks to 40% if the JT9 decoder is
invoked. > I am afraid that invoking 3 instances of the JT9 decoder at (almost) the same time is not a good idea. > > 73, Rik ON7YD - OR7T
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