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Re: LF: 500 kHz WSJT JT4A

To: [email protected]
Subject: Re: LF: 500 kHz WSJT JT4A
From: Andy Talbot <[email protected]>
Date: Thu, 21 Jan 2010 22:29:38 +0000
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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.
2010/1/21 Gary - G4WGT <[email protected]>
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 <[email protected]>
may be egg-sucking-lecture, but you have got JT4A set haven't you?.  Not B...G.
2010/1/21 Gary - G4WGT <[email protected]>
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 <[email protected]>

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

Andy
www.g4jnt.com

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2010/1/21 Gary - G4WGT <[email protected]>
LF,

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

Gary - G4WGT.



2010/1/21 Gary - G4WGT <[email protected]>
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.









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