Re: LF: 500 kHz WSJT JT4A

[Andy Talbot <andy.g4jnt@googlemail.com>]

Also, Gary,

what frequency Tol setting do you have?   I see Jim's freq reading is -77Hz, so if you have Tol set to 50Hz, for example, it'll miss Jim's signals. 

 

It defaults to 400Hz at startup, so a lower value will have to have been set somehow.

Andy
www.g4jnt.com

2010/1/21 Andy Talbot <andy.g4jnt@googlemail.com>

Ah...

I wonder.

 

Jim's DT setting for your sigs  is around +2 seconds.   Which means in the opposite direction it would be -2s.   This is a bit marginal.   The WSJT modes were designed originally for EME, and I think the acceptable time window is assymetric, being around 2s negative and up to 6s positive to allow for the EME delay.

 

But if you're decoding JT65A on HF all OK, not too sure - depends if it has the same time-search margin.  Would have thought it does.   Unless Jim's timing is out.....?

 

Just a thought.   WSPR is probably more tolerant of timing and it certainly doesn't need to be assymetric in its search.

Andy
www.g4jnt.com

2010/1/21 Gary - G4WGT <g4wgt@tiscali.co.uk>

OK Andy,

Any suggestion is welcome but yes I do have it set for JT4A, I am currently on 80m decoding fine with JT65A.

Looked at the Rate in & out in setup/options & are both set for 1, the rate shown at the bottom left is usually very close to 1.0003. I would say that is OK.

I will try again tomorrow.

Thanks again.

Gary - G4WGT.

2010/1/21 Andy Talbot <andy.g4jnt@googlemail.com>

may be egg-sucking-lecture, but you have got JT4A set haven't you?.  Not B...G.

Andy
www.g4jnt.com

2010/1/21 Gary - G4WGT <g4wgt@tiscali.co.uk>

Andy,

You wrote :-

Watch & check your sampling rate calibration. for this mode.

Is that displayed in the box at the bottom left, if so then it is always within the recommended figures. I read in the user guide to watch those figures for stability & I have never seen it go outside the range specified in the manual.

There is an "Enable Diagnostics" in the setup menu but no description in the use guide (WSJT6), it must be an addition in 7.03 but not documented. Is that of any help to me?

73

Gary - G4WGT.

2010/1/21 Andy Talbot <andy.g4jnt@googlemail.com>

Watch & check your sampling rate calibration. for this mode.

Andy
www.g4jnt.com

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2010/1/21 Gary - G4WGT <g4wgt@tiscali.co.uk>

LF,

Station calling about 503.670 kHz but no decode. Not sure why :-((

Gary - G4WGT.

2010/1/21 Gary - G4WGT <g4wgt@tiscali.co.uk>

LF,

I am currently transmitting a WSJT JT4A test signal on 503.600 kHz at each even minute, the ERP is estimated at 200 mW.

In a while I will change the message to a CQ call & watch for any JT4A replies.

73,

Gary - G4WGT.