_WSJT-X_ v1.7 introduces a number of new features designed for use on the VHF and higher bands. These features now include: - *JT4*, a mode particularly useful for EME on the microwave bands - *JT9* fast modes, useful for scatter propagation on VHF bands - *QRA64*, a mode for EME using a "`Q-ary Repeat Accumulate`" code, a low-density parity-check (LDPC) code using a 64-character symbol alphabet - *MSK144*, a mode for meteor scatter using a binary LDPC code and Offset Quadrature Phase-Shift Keying (OQPSK). The resulting waveform is sometimes called Minimum Shift Keying (MSK). - *ISCAT*, intended for aircraft scatter and other types of scatter propagation - *Echo* mode, for detecting and measuring your own lunar echoes - *Doppler tracking*, which becomes increasingly important for EME on bands above 1.2 GHz. - *Auto-sequencing* of transmitted messages for the fast modes with forward error control [[VHF_SETUP]] === VHF Setup To activate the VHF-and-up features: - On the *Settings | General* tab check *Enable VHF/UHF/Microwave features* and *Single decode*. - For EME, check *Decode at t = 52 s* to allow for extra path delay on received signals. - If you will use automatic Doppler tracking and your radio accepts frequency-setting commands while transmitting, check *Allow Tx frequency changes while transmitting*. Transceivers known to permit such changes include the IC-735, IC-756 Pro II, IC-910-H, FT-847, TS-590S, TS-590SG, TS-2000 (with Rev 9 or later firmware upgrade), Flex 1500 and 5000, HPSDR, Anan-10, Anan-100, and KX3. To gain full benefit of Doppler tracking your radio should allow frequency changes under CAT control in 1 Hz steps. NOTE: If your radio does not accept commands to change frequency while transmitting, Doppler tracking will be approximated with a single Tx frequency adjustment before a transmission starts, using a value computed for the middle of the Tx period. - On the *Radio* tab select *Split Operation* (use either *Rig* or *Fake It*; you may need to experiment with both options to find one that works best with your radio). - On the right side of the main window select *Tab 1* to present the traditional format for entering and choosing Tx messages. The main window will reconfigure itself as necessary to display controls supporting the features of each mode. - If you are using transverters, set appropriate frequency offsets on the *Settings | Frequencies* tab. Offset is defined as (transceiver dial reading) minus (on-the-air frequency). For example, when using a 144 MHz radio at 10368 MHz, *Offset (MHz)* = (144 - 10368) = -10224.000. If the band is already in the table, you can edit the offset by double clicking on the offset field itself. Otherwise a new band can be added by right clicking in the table and selecting *Insert*. image::Add_station_info.png[align="center",alt="Station information"] - On the *View* menu, select *Astronomical data* to display a window with important information for tracking the Moon and performing automatic Doppler control. The right-hand portion of the window becomes visible when you check *Doppler tracking*. image::Astronomical_data.png[align="center",alt="Astronomical data"] Three different types of Doppler tracking are provided: - Select *Full Doppler to DX Grid* if you know your QSO partner's locator and he/she will not be using any Doppler control. - Select *Receive only* to enable EME Doppler tracking of your receive frequency to a specific locator. Your Tx frequency will remain fixed. - Select *Constant frequency on Moon* to correct for your own one-way Doppler shift to or from the Moon. If your QSO partner does the same thing, both stations will have the required Doppler compensation. Moreover, anyone else using this option will hear both of you without the need for manual frequency changes. - See <> for details on the quantities displayed in this window. === JT4 JT4 is designed especially for EME on the microwave bands, 2.3 GHz and above. - Select *JT4* from the *Mode* menu. The central part of the main window will look something like this: image::VHF_controls.png[align="center",alt="VHF Controls"] - Select the desired *Submode*, which determines the spacing of transmitted tones. Wider spacings are used on the higher microwave bands to allow for larger Doppler spreads. For example, submode JT4F is generally used for EME on the 5.7 and 10 GHz bands. - For EME QSOs some operators use short-form JT4 messages consisting of a single tone. To activate automatic generation of these messages, check the box labeled *Sh*. - Select *Deep* from the *Decode* menu. You may also choose to *Enable averaging* over successive transmissions and/or *Enable deep Search* (correlation decoding). image::decoding_depth.png[align="center",alt="Decoding Depth"] The following screen shot shows one transmission from a 10 GHz EME QSO using submode JT4F. image::JT4F.png[align="center",alt="JT4F"] === JT65 In many ways JT65 operation on VHF and higher bands is similar to HF usage, but a few important differences should be noted. Typical VHF/UHF operation involves only a single signal (or perhaps two or three) in the receiver passband. You may find it best to check *Single decode* on the *Settings -> General* tab. There will be little need for *Two pass decoding* on the *Advanced* tab. With VHF features enabled the JT65 decoder will respond to special message formats often used for EME: the OOO signal report and two-tone shorthand messages for RO, RRR, and 73. These messages are always enabled for reception; they will be automatically generated for transmission if you check the shorthand message box *Sh*. Be sure to check *Deep* on the *Decode* menu; you may optionally include *Enable averaging* and *Deep search*. The following screen shot shows three transmissions from a 144 MHz EME QSO using submode JT65B and shorthand messages. Take note of the colored tick marks on the Wide Graph frequency scale. The green marker at 1220 Hz indicates the selected QSO frequency (the frequency of the JT65 Sync tone) and the *F Tol* range. A green tick at 1575 Hz marks the frequency of the highest JT65 data tone. Orange markers indicate the frequency of the upper tone of the two-tone signals for RO, RRR, and 73. image::JT65B.png[align="center",alt="JT65B"] === QRA64 QRA64 is an experimental mode in the Version 1.7 alpha release of _WSJT-X_. Some details of the protocol are still subject to change, and some features of the decoder will almost surely change. In most ways you will find operation of QRA64 similar to JT65. The following screen shot shows examples of two QRA64A transmissions recorded over the EME path. The first (at 1554 UTC) shows G4SWX transmitting to K1JT at 144 MHz; the second shows VK7MO transmitting to G3WDG at 10 GHz. Notice the small red curve plotted below frequency 1000 Hz in the Wide Graph. Even though the VK7MO signal is hard to discern in the waterfall, the red curve shows that the decoder has accurately and reliably detected its synchronizing symbols, and the decode is successful. image::QRA64.png[align="center",alt="QRA64"] === ISCAT ISCAT is a useful mode for signals that are weak but more or less steady in amplitude over several seconds or longer. Aircraft scatter at 10 GHz is a good example. ISCAT messages are free-format and may have any length from 1 to 28 characters. This protocol includes no error-correction facility. === MSK144 Meteor-scatter QSOs can be made any time on the VHF bands at distances up to about 2100 km (1300 miles). Completing a QSO takes longer in the evening than in the morning, longer at higher frequencies, and longer at distances close to the upper limit. But with patience, 100 Watts or more, and a single yagi it can usually be done. The following screen shot shows two 15-second MSK144 transmissions from W5ADD during a 50 MHz QSO with K1JT, at a distance of about 1800 km (1100 mi). The decoded segments have been encircled on the *Fast Graph* spectral display. image::MSK144.png[align="center",alt="MSK144"] Unlike other _WSJT-X_ modes, the MSK144 decoder operates in real time during the reception sequence. Decoded messages will appear on your screen almost as soon as you hear them. To configure _WSJT-X_ for MSK144 operation: - Select *MSK144* from the *Mode* menu. - Select *Fast* from the *Decode* menu. - Set the audio receiving frequency to *Rx 1500 Hz*. - Set frequency tolerance to *F Tol 100*. - Set the *T/R* sequence duration to 15 s. - To match decoding depth to your computer's capability, click *Monitor* (if it's not already green) to start a receiving sequence. Observe the percentage figure displayed on the _Receiving_ label in the Status Bar: image::Rx_pct_MSK144.png[align="center",alt="MSK144 Percent CPU"] - The displayed number (here 17%) indicates the fraction of available time being used for execution of the MSK144 real-time decoder. If this number is well below 100% you may increase the decoding depth from *Fast* to *Normal* or *Deep*, and increase *F Tol* from 100 to 200 Hz. NOTE: Most modern multi-core computers can easily handle the optimum parameters *Deep* and *F Tol 200*. Older and slower machines may not be able to keep up at these settings; at the *Fast* and *Normal* settings there will be a small loss in decoding capability (relative to *Deep*) for the weakest pings. - T/R sequences of 15 seconds or less requires selecting your transmitted messages very quickly. Check *Auto Seq* to have the computer make the necessary decisions automatically, based on the messages received. - For operation at 144 MHz or above you may find it helpful to use short-format *Sh* messages for Tx3, Tx4, and Tx5. These messages are 20 ms long, compared with 72 ms for full-length MSK144 messages. Their information content is a 12-bit hash of the two callsigns, rather than the callsigns themselves, plus a 4-bit numerical report, acknowledgment (RRR), or sign-off (73). Only the intended recipient can decode short-messages. They will be displayed with the callsigns enclosed in <> angle brackets, as in the following model QSO CQ K1ABC FN42 K1ABC W9XYZ EN37 W9XYZ K1ABC +02 R+03 RRR 73 NOTE: There is little or no advantage to using MSK144 *Sh* messages at 50 or 70 MHz. At these frequencies, most pings are long enough to support standard messages -- which have the advantage of being readable by anyone listening in. === Echo Mode *Echo* mode allows you to make sensitive measurements of your own lunar echoes even when they are too weak to be heard. Select *Echo* from the *Mode* menu, aim your antenna at the moon, pick a clear frequency, and toggle click *Tx Enable*. _WSJT-X_ will then cycle through the following loop every 6 seconds: 1. Transmit a 1500 Hz fixed tone for 2.3 s 2. Wait about 0.2 s for start of the return echo 3. Record the received signal for 2.3 s 4. Analyze, average, and display the results 5. Repeat from step 1 To make a sequence of echo tests: - Select *Echo* from the *Mode* menu. - Check *Doppler tracking* and *Constant frequency on the Moon* on the Astronomical Data window. - Be sure that your rig control has been set up for _Split Operation_, using either *Rig* or *Fake It* on the *Settings | Radio* tab. - Click *Enable Tx* on the main window to start a sequence of 6-second cycles. - _WSJT-X_ calculates and compensates for Doppler shift automatically. As shown in the screen shot below, when proper Doppler corrections have been applied your return echo should always appear at the center of the plot area on the Echo Graph window. image::echo_144.png[align="center",alt="Echo 144 MHz"] === VHF+ Sample Files Sample recordings typical of QSOs using the VHF/UHF/Microwave modes and features of _WSJT-X_ are available for <>. New users of the VHF-and-up features are strongly encouraged to practice decoding the signals in these files.