Quick-Start Guide to WSJT-X 2.7 and QMAPJoe Taylor, K1JT – March 8, 2023

Introduction: WSJT-X 2.7 introduces enhancements to the Q65 decoder and an entirely newcompanion program, QMAP. These additions are of particular interest to those engaged in
Earth-Moon-Earth (EME) communication, but other applications may be found for them aswell. QMAP is derived from MAP65, an older program used since 2007 for EME, mainly on
the 2 m band. QMAP provides single-channel receive-only capabilities for any of the 60second submodes of Q65. It allows you to monitor all traffic in a 90 kHz subband while
conducting EME QSOs in the usual way with WSJT-X.
Q65 Pileup: WSJT-X 2.7 has a new feature to assist DX operators using Q65 in pileup
circumstances with many simultaneous callers and very weak signals. Select Special
operating activity and Q65 Pileup on the Settings | Advanced tab (or right-click on themain window’s Q65 button), thereby configuring the program for QSOs exchanging 4-character
locators instead of signal reports. (Such QSOs are also used in NA VHF, WW Digi, andARRL Digi contests. You can work the pileup operator with older versions of WSJT-X byselecting one of these options.) Standard replies to a CQ start with Tx2 rather than Tx1, andmessages can have any one these general forms:
Call_1 Call_2 Grid
Call_1 Call_2 R Grid
Call_1 Call_2 RRR
Call_1 Call_2 RR73
Call_1 Call_2 73
With Q65 Pileup enabled, WSJT-X remembers the most recently decoded calls and locators,
up to a maximum of 40, and uses these for possible a priori (AP) decoding (see Section 12.2of the WSJT-X User Guide for more details). With marginal signals and significant fading, thisfeature can improve decoding sensitivity by more than 3 dB. The table below shows measured
threshold sensitivities (50% decoding probability) for Q65-60A in WSJT-X versions 2.6.1 and
2.7.0, under circumstances where information about the calling station is (or is not) available,
and when the signal is within F Tol of the selected Rx frequency or somewhere else in thereceived passband. You can see that with Q65 Pileup activated, WSJT-X 2.7.0 provides
single-transmission sensitivities in the range -29.5 to -30.9 dB for callsigns in its recentlydecoded list. Averages of several transmissions can be decoded down to about -34 dB.
Decoding circumstances

WithinF Tol ?
NNYNYYNo useful information about callers
Correct DxCall and DxGrid
No useful information about callers
Q65 Pileup, call and grid in list
Q65 Pileup, call and grid in list
Correct DxCall and DxGrid
1v2.6.1
(dB)
-27.4
-27.4
-27.7
n/an/a-30.9

v2.7.0
(dB)
-27.4
-27.4
-27.7
-29.5
-30.9
-30.9

With Q65 Pileup activated, the Active Stations window provides a simple list in decodedfrequency order of calls, locators, Moon elevation in degrees, and the time in hours since themost recent decode of that station. Click on a line to send message Tx3 to that station.

Calls are removed from the list if the Moon is more than 5 degrees below the horizon, Age isgreater than 24 h, or a QSO with that station is logged. You can delete a particular entry byholding down the CTRL key while clicking on that line, or clear the entire list by invoking Eraselist of Q65 callers on the File menu.
With special attention to its wide variety of applications, we continue to improve the Q65
decoder and user interface in other ways. Version 2.7 has much better performance whenaddressing multiple signals spread over the received passband, and the orange and red Q65
Sync plots have been made more useful. The decoder has minor changes to parameters that
distinguish its Fast, Normal, and Deep settings, in many circumstances making it moresensitive, or faster, or both. I generally use the Fast setting, keeping in mind that doubleclicking on a trace in the waterfall will always invoke Deep decoding to provide a closer look ata marginal signal.
QMAP is available only for the Windows platform. It was developed to provide wideband
decoding of Q65 signals in any one of the 60-second submodes. We use QMAP routinely withthe 1296 MHz EME setup at W2ZQ, club station of the Delaware Valley Radio Association,and all our operators like it. QMAP works in close cooperation with WSJT-X, receiving anddecoding all traffic in a 90 kHz EME subband, say 1296.035 to 1296.125 MHz. As an
example, in a single minute during the ARRL EME contest on November 12, 2022, QMAP
decoded the EME traffic shown in the screen shot on the next page. Frx is the received synctone frequency, while Fsked is the suggested “Constant frequency on Moon” (CFOM)
frequency on which to call that station.

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QMAP decodes are forwarded via shared memory to WSJT-X, where calls, locators, andfrequencies are listed in the Active Stations window for inspection and selection by theoperator. In this usage the Active Stations window looks slightly different. The screen shoton the next page shows Q65-60C traffic decoded at W2ZQ over a ten-minute interval during
the EME Contest. Here Age is the number of Rx sequences since the most recent decode ofthat station. The special mark # after Age indicates a “new initial” or new contest QSO, i.e., astation not yet present in file wsjtx.log in the Log directory. Similarly, an asterisk * indicates astation whose most recent decoded transmission contained CQ, RR73, or 73, and whose
operator is presumably ready to start another QSO.
EME QSOs are conducted in WSJT-X, using its features for rig control, Doppler compensation,and standard message sequencing in the usual way. Click on a line in the Active Stations
window to call that station. The program will generate appropriate messages, set yourtransceiver’s dial frequency suitably for CFOM Doppler tracking, and transmit in the next
proper Tx sequence.

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By checking the box Wanted only you can limit the displayed list of active stations to those notalready present in wsjtx.log, , as shown here for the same ten-minute interval.

Similarly, by checking Ready only you can limit the displayed list to those ready to be called
for another QSO:QMAP uses Linrad (by SM5BSZ) as a front end, providing optional noise blanking and control
for a wide variety of SDR hardware. At W2ZQ we use the RSPduo (by SDRPlay) in its singletuner mode, and version 05.02 of Linrad. Digital in-phase and quadrature (IQ) baseband data
are forwarded from Linrad to QMAP as UDP packets, at the required 96000 Hz sample rate.
Parameter files for suitable Linrad configuration are available on request.

5Configuring QMAP is simple and straightforward. Go to File | Settings … and enter yourcallsign and 6-character Maidenhead locator as My Call and My Grid on the Station tab.

You may need to set suitable directories for optional saved files of IQ data, and for the outputof Moon and Sun tracking information that might be used by another program to control yourantenna.
You can enter necessary frequency adjustments in the fields Fcal (Hz) and Fadd (MHz). At
W2ZQ the RSPduo accepts IF from an Icom IC-9700, where 1296 MHz has been downconverted to 367 MHz. We tell Linrad to receive a 90 kHz band centered at 367.08 MHz, andthe value Fadd = 929 MHz informs QMAP that our on-the-air received passband is actuallycentered 929 MHz higher, at 1296.080. We make an additional correction Fcal = 150 Hz tocorrect a small error in the RSPduo’s master clock frequency.

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