=== VHF Setup _WSJT-X_ v1.7 builds on for VHF and higher bands first introduced in v1.6. These features now include: - *JT4*, a mode particularly useful for EME on the microwave bands - *QRA64*, a mode for EME using a "`Q-ary Repeat Accumulate`" code, a low-density partity-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), a waveform also known as Minimum Shift Keying (MSK) - *ISCAT*, intended for other types of scatter propagation. - *Echo* mode, for detecting and measuring your own lunar echoes - Automatic *Doppler tracking* for the EME path To activate the VHF-and-up features: - Check the box labeled *Enable VHF/UHF/Microwave features* on the *Settings | General* tab. - In most cases you will also want to check *Single decode*. - If you will be doing EME, check the box *Decode at t = 52 s* to allow for the EME path delay on received signals - If you will use automatic Doppler tracking and your radio accepts QSY commands while transmitting, check the box *Allow Tx frequency changes while transmitting*. Transceivers that allow such changes include the IC-735, IC-756 Pro II, IC-910-H, FT-817, FT-847, FT-857, FT-897, TS-590S, TS-590SG, TS-2000 (with Rev 9 firmware upgrade), Flex 1500 and 5000, HPSDR, Anan-10, Anan-100, and KX3. 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). - If your radio does not accept commands to change frequency while transmissing, Doppler tracking is accomplished by making a single Tx frequency adjustment before transmitting, using a value computed for the middle of the Tx period. - The main window reconfigures itself as necessary to include controls supporting features of each mode. For example, in JT4 mode the central part of the main window might look something like this: image::VHF_controls.png[align="center",alt="VHF Controls"] - On the *View* menu, select *Astronomical data* to display a window with important information for tracking the Moon and performing automatic Doppler control. Check the box labeled *Doppler tracking* to ensure that the right-hand portion of the window is visible. 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. The hypothetical "`man in the moon`" would copy all of you on the selected nominal frequency. - In the example depicted above, the moon-based nominal frequency is 100 kHz above the stated band edge, or 10368.100 MHz for the 10 GHz band. The home station two-way self Doppler shift is +24366 Hz, so the one-way shift is +12183 Hz. Therefore, the receive frequency is set to 10,360.112183 Hz. When a transmission is started, the frequency will be reset to 12183 Hz _below_ the nominal on-the-moon frequency. === EME with JT4 - Select *JT4* from the *Mode* menu. - Select the desired submode, which determines the tone spacing. Higher 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 10 GHz band. - If using a transverter, set the appropriate offset 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"] - The JT4 decoder in _WSJT-X_ includes optional facilities for averaging over successive transmissions and also correlation decoding, also known as "`Deep Search`". Either or both of these options may be selected from the *Decode* menu. image::decoding_depth.png[align="center",alt="Decoding Depth"] - By convention, EME with JT4 can use "`short form`" messages consisting of a single tone. To activate automatic generation of these messages, check the box labeled *Sh* on the main window. IMPORTANT: Thanks to G3WDG, many additional hints for using JT4 and Echo mode on the EME path are available in {jt4eme}. === EME with JT65 TBD ... === EME with QRA64 TBD ... === Meteor Scatter with MSK144 TBD ... === Scatter Propagation with ISCAT TBD ... === 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. - On the Astronomical Data window check *Doppler tracking* and *Constant frequency on the Moon* - Choose your desired test frequency using the *Frequency above nominal band edge* controls. - Be sure that your rig control has been set up for _Split Operation_ (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. Your return echo should always appear at the center of the plot area on the Echo Graph window, as in the screen shot below. image::echo_144.png[align="center",alt="Echo 144 MHz"]