Satellites (SAT)

The SAT panel in the Rig window: choosing the satellite and transponder, when it passes and where it is, frequencies with Doppler, Doppler tracking and saving QSOs as satellite QSOs. You open it in the Rig window: Menu → Satellites (SAT) - the window grows to the right. The same menu item hides the panel.

Radios: MAIN receives, SUB transmits (like split)

Working satellites is like any split: MAIN = receive (downlink), SUB = transmit (uplink). MAIN is active all the time - SUB cannot be made active - but you tune the SUB frequency with the mouse as usual. The Split button shows “SAT”.

• Two radios (e.g. a 70 cm radio in MAIN and a 2 m radio in SUB, or an SDR receiver via Hamlib in MAIN) - full support: both frequencies from the radios, Doppler tracking of both. The TX button of the Rig window keys the SUB radio.
• One radio (e.g. IC-705, FT-817; a radio can be in one row only) - when you click Doppler the program switches split on in the radio: VFO A = receive (downlink), VFO B = transmit (uplink), both with Doppler and the transponder mode. The SUB row shows VFO B. The TX button keys the radio and the radio transmits from VFO B - the mic PTT too. A radio without split (or a split the radio did not accept) - receive only with Doppler and a message in the panel; then you set the uplink yourself.
• Swapped radios (MAIN on the uplink, SUB on the downlink) - a red message in the panel. Swap the radios: ≡ → MAIN ⇄ SUB radio; otherwise you would transmit on the receive frequency. Transverters belong to the rows, not to the radios - set them again after the swap (the T button).

Choosing the satellite and transponder

The button with the satellite name opens a list by availability: first the satellites visible now (elevation and LOS time), then the nearest passes (AOS and the highest elevation), at the end the satellites without a pass in the next 48 hours. No satellite (QSO without SAT) - a normal QSO.

The transponder button shows the transponders and repeaters of the satellite, e.g. V/U FM CTCSS 67.0 (FM) or V/U linear, inverting (SSB / CW; the top of the uplink band matches the bottom of the downlink). When you tune the radio to another segment (e.g. the QO-100 band plan segments or mode A / B of AO-7), the panel chooses the right transponder by itself.

Satellite data

• TLE (orbital elements) - CelesTrak, amateur group, refreshed automatically every 2 days.
• Transponders - SatNOGS DB (active amateur satellites), every 7 days. The name for the log is the OSCAR designation (SO-50, AO-91, QO-100; ISS = ARISS), as in LoTW.
• The TLE button downloads both at once. Without internet (or when internet is locked in the configuration) the program uses the last files from the DATA\SAT folder next to the program.
• Your own corrections: the DATA\SAT\satellites_user.csv file (same format as transponders.csv) - it wins over SatNOGS. A line with frequencies = an extra transponder, a line without them = your own name / LoTW name for a NORAD number.

The program computes the satellite positions itself (SGP4 model) for the My Grid locator from the LogBook configuration. Without a locator the panel shows a red message and does not compute azimuth and elevation.

Doppler tracking

A satellite moves fast, so the frequencies change during the pass (on 70 cm by up to ±10 kHz). After you click Doppler the program keeps one frequency on the satellite and retunes the radios every second:

• MAIN (receive) = downlink with Doppler, SUB (transmit) = uplink with Doppler - with one radio VFO A and VFO B; radio modes from the transponder (FM, USB / LSB, CW; AFSK / 9k6 packet, e.g. ISS APRS - FM, BPSK - USB);
• turning the knob (on the radio or with the mouse on the display) moves the point on the transponder - on a linear one the other frequency follows;
• one radio: a radio on another band (e.g. on HF) goes to the downlink with Doppler and the transponder mode when you click Doppler, and VFO B to the uplink (split in the radio, checked after 3 s); while transmitting the program changes nothing, and right after it the receive side comes back from the calculation; moved by hand to another band it stays there (“Doppler waits”; switch Doppler off and on to come back); switching Doppler off turns the split off;
• double-click a frequency (RX or TX row of the panel) - Doppler from scratch: satellite point from the current RX, TX calculated from the transponder and sent again (e.g. when VFO B drifted away from RX); while transmitting - right after it;
• tracking switches off by itself at LOS, when the satellite or transponder changes and when the panel or the Rig window is hidden.

Saving QSOs

With the Log SAT LED on, a QSO saved in the log gets: PROP_MODE = SAT, SAT_NAME (e.g. SO-50), SAT_MODE (e.g. V/U), the transmit frequency and band (uplink) and the receive ones (FREQ_RX, BAND_RX - downlink) at the moment of saving. That is enough for LoTW and ADIF export.

• A QSO from WSJT-X / JTDX (e.g. FT8 via QO-100) gets the SAT fields when its band is the uplink or downlink band.
• A QSO typed in by hand on another band (e.g. HF with the panel open) stays a normal QSO.
• Choose No satellite or switch Log SAT off to save QSOs without satellite data.

Satellite map and passes

Map - the globe of the QSO map (the same style; dragging rotates, the mouse wheel zooms, a double click returns to the whole globe; the map style - the button in the upper right corner) with the satellites as icons: a space station (ISS), a geostationary satellite (QO-100), a satellite on an elliptical orbit (HEO) and a small satellite (all others). Satellites and orbits are in space above the globe, at their flight altitude (orbits higher than 1600 km are compressed, so that GEO fits in the window); whatever is behind the Earth is hidden.

• List on the left - (All satellites) or one satellite. Under the name - the next pass over your station (AOS, max El); the ones visible now are at the top, in bold, with their elevation. Choosing on the list or clicking an icon on the map chooses the satellite in the SAT panel too - with Doppler tracking on, the panel stays on its satellite and the map shows the chosen one.
• Show satellites - all, visible now, or visible within 1, 3, 6, 12 or 24 hours.
• One satellite: its orbit one revolution ahead and a bit back (dashed); the part where the satellite will be visible from your station - thick, in a warm colour, with the AOS and LOS times; a line down to the point under the satellite; the footprint - a circle on the Earth in the colour of the orbit class (stations inside it can work through the satellite; filled more strongly - your station is inside); a box with data: altitude, period, azimuth, elevation, range, pass. A satellite behind the Earth - a dashed circle.
• All satellites: orbits of all on the list in the colours of altitude classes - LEO below 600 km, 600-1000 km, above 1000 km, GEO, HEO (legend in the lower right corner); an orbit fades in the direction of flight.
• Satellites visible from your station glow, and a red bearing line ("laser") leads to them from your station (with one satellite chosen - only to it). Behind every satellite there is a trail - you can see where it is flying; an orange part of the trail - it was visible from your station then. Lines - a classic thin track line behind every satellite (with the orange part too): trails and lines, only trails, only lines or neither (icons only).
• Trails, Lines, Footprint, Names, Orbits - map elements. The program remembers these settings and the list filter.

Animation - the bar at the bottom: Start / Stop, Now (real time - the LED is on), speed from ×1 to ×1200 (e.g. ×600 = 10 minutes per second) and the timeline from a day back to 30 days ahead. At the top of the timeline a narrow overview of the whole month: days, passes of the chosen satellite and the frame of the visible part - drag it or click a day. Below - the visible part (from 1 hour to 7 days) with the passes of the chosen satellite (bar height = max El) or of all on the list; « » scroll, – + change the scale (also the mouse wheel and Ctrl + wheel). A click or dragging on the timeline sets the map time - e.g. the day after tomorrow in the evening without playing the animation. Passes a few days ahead and further are approximate (TLE data ages - the TLE button in the panel downloads fresh data). Rotating and zooming the map during the animation does not stop it, and the night shadow moves smoothly with the map time. Animation frames are drawn by background threads in step with the monitor refresh (like the rotating QSO map) - about 60 frames per second on a strong processor (12 or more threads), 30 on a weaker one and under Wine (Linux); over remote desktop, in the 32-bit program and on a processor with fewer than 6 threads the map is drawn in a simpler way, less often.

Passes - passes in the next 24 hours: AOS, the highest elevation, LOS (with azimuths), duration, transponders. All satellites (LED) - all from the database, otherwise only the chosen one. Max El ≥ - skips low passes. Passes in progress are green. A double click chooses the satellite in the panel.

Examples

A. An FM satellite (e.g. SO-50) on two radios

1. MAIN = a 70 cm radio (receive), SUB = a 2 m radio (transmit) (≡ in each row). Menu → Satellites (SAT).
2. Choose SO-50 and the V/U FM CTCSS 67.0 transponder. Switch the 67 Hz tone on in the transmitting radio.
3. Before AOS click Doppler - the radios go to FM and to the frequencies with Doppler; point the antenna by azimuth and elevation or with a rotor: Rotor → Track.
4. Transmit with the TX button of the Rig window or the PTT of the SUB radio. Save the QSO in the log - the SAT fields fill in by themselves.

B. An FM satellite on one radio

One row with the radio (e.g. IC-705) on the downlink (436.795 MHz for SO-50) or on any other band - clicking Doppler sets VFO A to the downlink, VFO B to the uplink (145.850 MHz) and switches split on in the radio; both VFOs follow the Doppler shift. Switch the 67 Hz tone on in the radio. Transmit with the TX button or PTT - the radio transmits from VFO B. Message “the radio did not accept split” - try Hamlib.

C. A linear satellite (e.g. RS-44) - SSB / CW

Two radios: MAIN on the 70 cm downlink, SUB on the 2 m uplink. An inverting transponder: uplink LSB, downlink USB - after you click Doppler the program sets the modes itself. You look for stations with the MAIN knob - the uplink follows it.

D. QO-100 (geostationary)

The 2.4 GHz uplink from a 2 m radio through a transverter (LO 2256 MHz), receive from an LNB converter (LO 9750 MHz) to a radio or SDR on 739 MHz. Set the transverters: the T button → SUB Typical → QO-100 ↑ 144 → 2400 MHz, MAIN → QO-100 ↓ LNB 10489 → 739 MHz. The Rig window shows the true frequencies (2 400 250 / 10 489 750 kHz), and the log saves QO-100, S/X. QO-100 is always visible - the Doppler shift is tiny.

More about transverters: Rig window. Problems with the SAT panel: Troubleshooting.