Hi Guys, Here are my thoughts
1 Force users to calibrate on installing WSPR. 2. Remind them evey 10 days or so to recalibrate 3 . Invite them to change the default TX frequency. This morning I have at least 6 stations on 7.040100 + or -2 Hz and only the strongest gets decoded Keep up the good work 73 Victor ----- Original Message ----- From: "Joe Taylor" <j...@princeton.edu> To: "WSJT software development" <wsjt-devel@lists.sourceforge.net> Date: Mon, 18 May 2015 21:09 +0700 Subject: Re: [wsjt-devel] Dial calibration errors > A few more thoughts about dial calibration errors. > > A couple of days ago I put my TS-2000 radio through the calibration > procedure described in Appendix C of the WSPR 4.0 User's Guide > http://physics.princeton.edu/pulsar/K1JT/WSPR_4.0_User.pdf > > The procedure takes about half an hour, end to end, yielding the values > of two constants A and B. These constants appear in the equation > > d = A + B*f > > where d is the radio's dial error in Hz and f is the received frequency > in MHz. In my case the constants are A = 2.14 Hz and B = 1.6254. I > note that the value of A has remained constant, but several years ago B > was somewhat smaller (B = 1.2885 in 2011), so the master oscillator in > my TS-2000 has aged a bit. > > From the values of A and B I computed the dial error for each amateur > band and entered those values (expressed in MHz) in the "Offset" column > of the WSJT-X Settings | Frequencies tab. Frequencies reported for my > WSPR decodes now agree with those reported by Steve, K9AN, to within 1 > Hz. (Steve's receiver uses GPS-disciplined oscillators, so his WSPR > reports are a good standard for comparison.) > > It might be handy to permit a user of WSJT-X to enter values for A and B > and have the program calculate the resulting "Offset" values for the > Frequencies tab. The resulting system behavior is very sensible, in my > opinion. When WSPRing on 20 meters, for example, my TS-2000 dial now > reads 14.09562 MHz. WSJT-X intentionally sets the radio about 24 Hz > high on this band, to compensate for its dial error. > > The dial frequency displayed on the WSJT-X main window is the corrected > value, 14.095 600 MHz. > > -- 73, Joe, K1JT > > On 5/13/2015 10:48 AM, Joe Taylor wrote: > > Hi all, > > > > One of the fun things about WSPR is the frequency accuracies that > > are involved. Having WSPR mode in WSJT-X motivates some serious thought > > about how best to handle frequency calibration errors in transceivers. > > > > Typical dial readout errors in modern radios are a few parts per million > > -- for example, a 20 Hz error at 14 MHz. For JT65 or JT9 such > > discrepancies are not very important. But the WSPR sub-bands in > > conventional use since 2008 are only 200 Hz wide, and we'd like to use > > all of that range effectively. If my transceiver's dial reads 20 Hz > > low, and yours reads 20 Hz high, and we both set our dials to the > > conventional 14.0956 MHz for 20 meters, after setting our WSPR Tx > > frequencies at random within the 200 Hz sub-band there's something like > > a 20% chance that we won't decode one another. > > > > Earlier production versions of WSPR have handled these issues in a > > rather sophisticated way. The User's Guide includes detailed > > instructions for determining calibration constants for your transceiver > > using over-the-air signals (see Appendix C of > > http://physics.princeton.edu/pulsar/K1JT/WSPR_3.0_User.pdf ). The > > resulting accuracies can be better than 1 Hz. > > > > If CAT control is in use and "Enable frequency correction" is ticked on > > WSPR's "Advanced Setup" window, frequencies sent to the radio are > > adjusted so as to compensate for the dial errors. For example, if > > 14.0956 MHz has been requested, the command for 14095620 Hz may be sent > > to the radio. > > > > I picture this being implemented in WSJT-X in a similar way. In this > > example, the radio dial would read 14.096520. I'm suggesting that the > > frequency readout on the WSJT-X screen would read 14.095600, the > > supposedly "true" frequency. > > > > Comments and suggestions would be welcome. > > > > -- 73, Joe, K1JT > > > > ------------------------------------------------------------------------------ > > One dashboard for servers and applications across Physical-Virtual-Cloud > > Widest out-of-the-box monitoring support with 50+ applications > > Performance metrics, stats and reports that give you Actionable Insights > > Deep dive visibility with transaction tracing using APM Insight. > > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > > _______________________________________________ > > wsjt-devel mailing list > > wsjt-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/wsjt-devel > > > ------------------------------------------------------------------------------ > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > _______________________________________________ > wsjt-devel mailing list > wsjt-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/wsjt-devel > ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ wsjt-devel mailing list wsjt-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/wsjt-devel
