Jt65

WSJT 65 (and variants) Discussion
VK2GOM
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Re: Jt65

Post by VK2GOM » Thu Oct 21, 2010 2:57 pm

Hi John,

Yes, you have to make the call on whether you Tx on the odd or even minute. If you are just listening, and hear a station you want to work calling CQ, the decision is already made for you - when you double click on his CQ you will automatically go into Tx on the next period, be it odd or even. ie. if he was even, you will Tx odd, if he was odd, you will Tx even.

Conversely, you may see a few people on the waterfall calling CQ or having QSO's on the even minute, so you might decide to slot into a gap and Tx on the odd minute and put out your own CQ call.

Of course, here is the catch: Whilst you are TX'ing you can't receive, so have to make a careful judgement. You could be calling CQ on even minutes for a few minutes, hear nothing, then stop - then realise there was rare DX all along also calling CQ during the same even minute!

Also, if you look in the received list, you might find a station you wanted to work faded out a few minutes back due to QSB... but you can work out what period he was Tx'ing in from the time shown next to his transmission. So you would set your Tx period to the opposite so he would hear you during his Rx period if the propagation became favourable again thus ensuring you aren't transmitting on top of eachother.

If you fancy running a test / example QSO sometime, we should manage it on 20m, or we can give it a try on 40m if my QRN ever backs off here... It's useful to have a 2m FM talkback channel too, to explain what's happening and what to do/click, and when. You will soon get the hang of it! The program might look daunting at first sight, but it's really not.

73 - Rob VK2GOM / G0MOH

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Re: Jt65

Post by VK2GOM » Thu Oct 21, 2010 4:13 pm

JT65a HF is laugh a minute at the moment... R7AU is calling CQ, and our overdriven VK4 friend is also calling him right on top of him in the same time period! Of course, me in Rx, I can see all this but they are oblivious to it. A simple illustration that it pays to sit and listen for a bit. I worked R7AU earlier. And as I was working him our VK4 friend was also calling him on top of R7AU's replies to me :roll:

And also right now there is a station transmitting half in one period, half in another. An example of incorrectly set PC clock. Timing has to be spot on!

73 - Rob VK2GOM / G0MOH
Last edited by VK2GOM on Fri Oct 22, 2010 1:47 pm, edited 1 time in total.

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Re: Jt65

Post by VK2FAK » Fri Oct 22, 2010 7:26 am

Hi all...

well tried out jt65a last night......first contact...

11:19 4 -19 1.2 495 B 15W DP TU 73
11:17 5 -19 1.1 495 B VK2FAK JA4CXX RRR
11:15 6 -17 1.2 493 B VK2FAK JA4CXX -13
11:13 3 -16 0.7 493 B CQ JA4CXX PM74

Played around a bit later also...but no luck there....most signals were from Europe and was looking like most people were not making contact....multiple calls by people and others trying to get the confirmation decode without luck...

But all is good.

P.S....wonder if someone had a quiet word with that VK4....his signal was down when I heard him again a bit later ...will see

John
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John Vk2FAK

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Re: Jt65

Post by VK2FAK » Fri Oct 22, 2010 10:01 pm

Hi all....

Well listening and working just a little on JT65a this evening......and following on from what Rob was saying about a Laugh a minute...

This evening there was a VK4 (different one ) who wanted to stay on his own spot on the waterfall regardless if the CQ call he was responding to was 500hz away.....he made the other station go to him....very strange....as most times in radio we learn to tune in the other station before attempting to make contact....just because you can do as he did does not mean you should.......the program is all done for us....but we have to make some effort.


John
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John Vk2FAK

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Re: Jt65

Post by VK3AUU » Sat Oct 23, 2010 5:18 am

That's OK John, sometimes there will be a stray weak carrier on the expected frquency and it stuffs up the decodes so you have to get the other station to shift. It happens quit a lot. Just go with the flow.

David

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Re: Jt65

Post by VK2FAK » Sat Oct 23, 2010 9:36 am

Hi all

Ahhh ok ..thats fair , I commented because I did read somewhere that it was not good operating practice .....but I guess if the other station moves across there is no big issue...

BUT....if he was able to decode the signal in the first place, whatever the problem was, could not have been having a big effect on his decoding....if more a local issue for him the other station would never know..

anyway it looked strange..I had never seen it ....live and learn..

John
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John Vk2FAK

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Re: Jt65

Post by VK2FAK » Thu Nov 04, 2010 7:49 am

Hi all....

How do you go about telling another operator the timing seems to be off....

Now this happened to me last week if I remember...but not to sure I was ,as i was decoding alright..

But the Message "check time" came up.... would that other operator have adjusted his time to send the message..?

Now if my timing was off, I am assuming I would never be able to decode that message "check time" ....

if its possible, all good...I don't mind assistance in getting it right.

Reason I ask is that I was watching last night and the same operator was calling time and again....but I could not decode it, by my clock he started to transmit on or around 1 sec prior to the minute.....again I assume this makes a difference....as the program is still on "idle" not on "receive"..


John
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John Vk2FAK

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Re: Jt65

Post by VK2GOM » Thu Nov 04, 2010 10:40 am

Hi John,

From the period start, assuming a proper time calibration, it allows up to about +3sec difference in Tx start time and it will still (generally!) successfully decode. Ideally, your clock needs to be as accurate as possible so you will find that an accurately set station will start to Tx within the first second of the transmission period, and end at about 48sec. Decodes flash up sometime shortly after that, depending on the speed of your PC.

However, if someone's clock is that far out they are Tx'ing actually over a period overlap, even sending them a 'clock out!' message on their freq might mean they won't decode it, since - you guessed it - their clock is out. A vicious circle problem!

Normally, these situations sort of rectify themselves... if they have any sense they eventually realise they are not decoding anything, and they can't decode responses they can see on the waterfall, so they look into it.

DIMENSION 4 is the way to go. Download, run it once, set an update interval and you never need to worry about your PC clock again. Most digital mode software that relies on accurate timing states in the very first paragraph of instruction that your PC clock must be accurately set, and maintained. But still people ignore it :roll:

73 - Rob VK2GOM / G0MOH

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Re: Jt65

Post by VK2FAK » Thu Nov 04, 2010 1:55 pm

Hi all...

Rob.....while your around...I was taking a look at the site ..Hamspots.....seems a great idea...so set my software up to send out data...

Now the question is....when you check your own reports on there and find there is a signal report that is no way mine..what can be done....or do we just simply ignore it..as its information only anyway..

a JA station had a report of me on the 12m band.....well I have not transmitted up there...

Just ignore it ....?

John..
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John Vk2FAK

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Re: Jt65

Post by VK2GOM » Thu Nov 04, 2010 4:21 pm

Hi John,

Could be all manner of things from the other station having his band-spotting parameters set incorrectly, to having your call pirated :shock: I think the latter is unlikely, and most probably cause is user error at the JA end.

PSK Reporter is popular for spotting data modes, including JT65a: http://pskreporter.info/pskmap.html The map can be interrogated to show contacts by anyone, country, or callsign, for any mode, on any band, within any set timeframe. A very useful facility.

It gives a quick snapshop map view of who is working who. When you run JT65-HF, if you tick the boxes 'enable PSK reporter' and 'enable RB' it will then upload to the site.

73 - Rob VK2GOM / G0MOH

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Re: Jt65

Post by VK2FAK » Fri Nov 05, 2010 7:52 pm

Hi all..


Hi Rob.....oh I was just watching you try to get the confirmation from that JA station....oh that was painful...lol..

Needed popcorn and a coke to watch that.....haha


John
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John Vk2FAK

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Re: Jt65

Post by VK2GOM » Fri Nov 05, 2010 8:36 pm

Hi John,

JA1KEV and I have been trying to complete a JT65a QSO for about a month now!! I think he's really after VK stations. Every time we attempt it, QSB kills our attempt! It will be a special QSL card the day we complete that one :D

73 - Rob VK2GOM / G0MOH

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