SatMe PC QO 100

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SatMe-PC — the QO-100 cockpit

← SatMe-PC guide · October 2026

QO-100's narrow band transponder on one screen: the receiver, the decoder and the log entry side by side, the transponder's waterfall below. The wide band (DATV) has its own page: DATV. See also QO-100 for the phone.

Where: workspace QO-100 (key 2).

In four steps

1. ▶ Démarrer la réception QO-100 (start QO-100 reception): one click starts the receiver (RTL-SDR dongle, ADALM-PLUTO, bladeRF, or a SatMe-Node's SDR — behind the LNB or a converter; the list beside it chooses which), puts it on QO-100 and sends its sound to the decoders and the log. ■ Arrêter (stop) stops it. If DATV holds that receiver: ■ Arrêter la DATV, puis QO-100 (stop DATV, then QO-100).
2. Click a signal in the waterfall: SatMe tunes to it in its mode (SSB, CW, FT8, SSTV, PSK31, RTTY) and opens the right decoder below.
3. Log the contact on the right: the satellite QO-100, the frequencies and the mode are already there.
4. The middle beacon is the reference: if the offset is large, tick Calage automatique (automatic calibration; Calage sub-tab).

Comment ça marche (how it works; a box, Compris ✕, got it, puts it away; ? Aide, help, opens it again) recalls these steps. Schéma (diagram) shows over the tab the chain in use, drawn by the Montage.

The receiver

• Descente (ciel) (downlink, sky), Montée (uplink), Niveau (level), Mode (SSB, CW, FT8, FT4, SSTV, PSK31, RTTY).
• Tuning: −1 k, −100, +100, +1 k, Balise médiane (middle beacon), Centre, Aller à (go to; sky MHz) then Aller; on the keyboard ← → 100 Hz, ↑ ↓ 1 kHz; the USB knob.
• Haut-parleur du PC (the PC's speaker), 🔈 Écouter ici (in this browser), Volume, Silencieux (squelch), CAG (AGC).
• Resuming after a stop: a banner « 📡 Tu recevais QO-100 quand SatMe s'est arrêté » (you were receiving QO-100 when SatMe stopped) offers Reprendre QO-100 (resume QO-100) or Non merci (no thanks); Réglages › Satellites › QO-100 au démarrage (QO-100 at start-up) does it by itself. Reception only.

The transponder waterfall

Transpondeur à bande étroite (narrow band transponder) card: Affichage (display: palette, contrast, brightness, memory flags), Mémoires (memories), Mesures (measurements; see SDR), Largeur (width; 500 to 20 kHz).

• Signal classifier: each signal named on the waterfall (SSB, CW, FT8, FT4, PSK31, RTTY, SSTV, carrier, beacons, wide digital, unknown), coloured by class with its confidence. It runs only while the page looks at it.
• Band plan (AMSAT-DL's) on the ruler, each segment's rule on hover. Emergency frequency (10 489.858 – 10 489.865): red outline and banner; SatMe never sends the uplink there to the rig by itself — only when tuned by hand.
• ⚠ LEILA: when the ground station's siren is heard (the station listened to is transmitting louder than the beacons), a red warning for 10 s.
• Bande large DATV — station sol, par Internet (DATV wide band — ground station, over the internet; box under the waterfall, unticked by default): the wide band under the narrow transponder; a click on a signal there tunes the DATV receiver to it.

The decoder

Under the receiver, Décodeur: Auto (that of the signal clicked), Phonie (voice), CW, FT8 / FT4 (▶ Décoder, Onglet FT8 complet ›, full FT8 tab), SSTV (Caler maintenant, Onglet SSTV ›), PSK31 / RTTY, Multiples.

• PSK31 / RTTY: Décoder, the mode, the audio frequency (auto), for RTTY 45.45 / 50 / 75 Bd, 170 / 425 / 850 Hz, inversé (reverse), the squelch; ⧉ copy, ⤓ save, ✕ clear. Time-stamped lines, your callsign in pink, the others one click away for the log entry.
• Multiple decoders (Multiples button, off by default): up to 4 channels taken from what the receiver sees, each with its decoder (FT8, FT4, CW, SSTV, voice, BPSK beacon, or plain listening; one SSTV, one voice and one beacon at most). Presets « FT8 + CW + phonie » and « FT8 + FT4 »; right-click (or Shift + click) on a waterfall signal: « Ajouter un décodeur ici » (add a decoder here). The sound stays the main tuning's, except the channel ticked 🔈; a click on a channel's frequency tunes the main receiver there.

The sub-tabs

Calage · Qualité · Balise · Mémoires · Poste & chaîne · Émission · Pointage, on the right under the log entry (and the Émission IC-9700 or Émission Pluto panel when the uplink goes through one of them).

• Calage (calibration): Caler sur la mesure (calibrate on the measurement); Calage automatique (the middle beacon measured every 5 s, the LNB's drift followed by small steps, never on a weak measurement); Verrouillage sur la balise (beacon lock; off by default, see below); the Écart mémorisé (stored offset); À la main (by hand): type where the beacon really falls (sky MHz), Appliquer (apply) or Remettre à zéro (reset).
• Qualité (quality): beacon over noise, offset, the LNB's error and drift over the hour, noise floor; Stations entendues (stations heard; a click: tune to it).
• Balise (beacon): the middle beacon's telemetry (400 bit/s BPSK, 256-byte coded frames in the manner of AO-40, 512-byte uncoded blocks). Décoder la balise (decode the beacon) puts a Multiple decoders channel on it, Retirer le canal (remove the channel), Essai (test; a made-up signal), octets bruts (raw bytes). Frames are kept in telemesure/.
• Mémoires: the frequencies memorised here (« QO-100 » tag), Nom (name) then Mémoriser ici (memorise here), Oublier (forget).
• Poste & chaîne (rig & chain): Appliquer au poste (apply to the rig; the CAT rig follows the cockpit, the followed satellite's Doppler is paused and the log records on QO-100) and Appliquer à la clé SDR (apply to the SDR dongle); the Transpondeur and Balayer tout QO-100 (scan all of QO-100; listening); the Chaîne de station (station chain; one or more, Nouvelle chaîne…, new chain, then Ajouter, add), the converters' OL descente and OL montée (downlink and uplink LO) — tied both ways to the « Chaîne QO-100 » lines of the converter and transverter table; Mesurer un oscillateur (measure an oscillator: a WebSDR reference and your rig on the same signal).
• Émission (transmission): the uplink profile (Fixe, Portable…), the estimated EIRP and suggested power, the Pluto's settings; see Transmitting on QO-100.
• Pointage (pointing): initial setup, dish pointing and the Sun.

Converters, calibration and alignment

• The converter and transverter table (Réglages › Poste et rotor › Convertisseurs et transverters): one line per box between the antenna and a device — RF band (sky side), LO, Inversé (inverted), and in front of what: Clé SDR (SDR dongle), CAT RX, CAT TX. The first active line that covers the frequency wins; QO-100 presets (9750 LNB to the dongle, LNB + down-converter to 2 m or 70 cm, 2400 uplink from 432 or 144). The cockpit's previous setting becomes the « Chaîne QO-100 » lines, tied to Poste & chaîne. With no converting line, nothing is sent to the rig (10 489 MHz is not an IC-9700 frequency): the Poste chip turns yellow. Hovering the cockpit's RX / TX frequencies: « FI envoyée au poste : … MHz » (IF sent to the rig). Details: Settings.
• Calibrer la clé SDR… (calibrate the SDR dongle; the table's button, or beside the ppm error of the SDR tab): on a QO-100 CW or PSK beacon, a GSM base station's FCCH tone or a known frequency, SatMe finds the peak, gives the dongle's error in ppm (Enregistrer, save) and, behind an LNB, its real oscillator (Corriger l'OL de cette ligne, correct this line's LO). One measurement cannot split the two errors: calibrate the dongle on a terrestrial reference first, then the beacon. Afterwards, reset the cockpit's calibration.
• Aligner… (align; Suivi tab, Fréquences (Doppler) card): for a linear transponder, step by step and kept per satellite — the downlink on the beacon (RX calibration), then the uplink with your own dots (TX offset; you key the transmitter yourself, the assistant never does), Mémoriser pour ce satellite (remember for this satellite).

A drifting LNB

An LNB without an external reference moves with temperature: a few hertz per second after power-up or in the sun, sometimes jumps of ±25 Hz within a second. FT8's tones are 6.25 Hz apart: such an LNB is enough to decode nothing. SatMe-PC does three things, all receive-only:

• Calibration that follows: when Calage automatique sees a real drift (over 1 Hz/s), the beacon is measured every second and the error taken from the straight line through the last 30 seconds. While FT8 or FT4 decode, steps fall only in the last second of the slot.
• Verrouillage sur la balise (Calage sub-tab, off by default): the middle beacon followed by a phase loop in the raw I/Q stream; its jumps are taken out of the whole transponder, smoothly; correction bounded to ±250 Hz, which lets go for 30 s if it gets too restless. Status: balise cherchée (searching for the beacon), or tient · N Hz rms ôtés (holding, N Hz rms removed).
• FT8 tolerating drift: a slot's shared drift (up to ±15 Hz/s) is found from the syncs, then taken out before a second reading.

This mitigates the problem without solving it: the real answer is an LNB held by a reference — for example a Twin LNB whose PLL takes an external 25 MHz, given by a Leo Bodnar GPSDO; one output to the MiniTiouner (which powers the LNB with 18 V), the other to the bladeRF through a DC-blocking injector. The Montage can draw this plan.

Transmitting on QO-100

Four ways up to the satellite:

• Narrow band in SSB, CW or FT8 — from the cockpit's Émission sub-tab, through the ADALM-PLUTO straight on 2.4 GHz or the IC-9700 with an up-converter: below.
• FT8 / FT4 through the IC-9700 — from the FT8/FT4 tab (Émission FT8/FT4 card), the rig put in USB-D by itself, never unattended: FT8 / FT4 transmit. In the digital segment, weaker than the beacon.
• SSTV (USB, digital or mixed segments) with a Pluto or a bladeRF: SSTV › Transmitting a picture.
• DATV (wide band): DATV: transmission.

Status (October 2026): narrow-band transmitting is written and tried on the simulated rig and with the Pluto held on its dummy-load stage. It has not yet been tried on the air with real hardware. Go step by step (see A first try) and watch your own signal against the beacon.

Two chains

• ADALM-PLUTO straight on 2.4 GHz — the Émission Pluto panel (right-hand column) holds the PTT. SSB (upper sideband) from the browser's microphone or a sound card of this PC: for FT8, WSJT-X's audio output to a virtual card or a loopback, source « carte son du PC ». CW: a text sent at the chosen speed (the PTT taken and given back by itself), or Touche (key) held: a carrier 700 Hz above the dial, keyed without clicks. The uplink follows the cockpit (liée, tied, while transmitting too) or is typed.
• IC-9700 + up-converter — the Émission IC-9700 panel (The IC-9700 transmitting). Uplink = the rig's frequency + the converter's LO (the CAT TX line of the converter table, tied to Poste & chaîne; measured), shown on screen; uplink and downlink tied without inversion; the beacon calibration corrects the downlink only. With Appliquer au poste ticked, the PTT is refused on a beacon or outside the band plan, and LEILA heard releases it. Mesurer l'OL sur ma descente (measure the LO on my downlink): SatMe keys the IC-9700 in CW (a carrier), finds it on the downlink and keeps the converter's real oscillator in the chain.

The band plan

The AMSAT-DL band plan is applied per mode, to the whole signal: SSB in the voice and mixed segments, CW in its own and the mixed one, digital in theirs and the mixed one. Never on a beacon, the broadcast or the emergency frequency. When the uplink falls outside, the panel says why and a button tunes the cockpit to the mode's starting frequency.

The Pluto's correction

The Pluto's oscillator is parked below the transponder (2399.6 MHz) and the signal moved up digitally: neither its leak nor its image reaches the satellite. Its crystal is off by a little — 1 ppm = 2.4 kHz on QO-100 — so give it its correction: typed in Hz at 2400 MHz, or measured on the downlink (on the air, in CW with the key down: the carrier found by the receiver calibrated on the beacon).

Uplink profiles: Fixe and Portable

The Émission sub-tab picks an uplink profile: the chain, the antenna, the amplifier (its power, its gain when known) and the cable losses. Fixe / Portable in one click, more as wanted (Modifier ce profil).

Antenna	Typical use
80 cm dish + POTY feed	the fixed station
35 cm dish + helix	portable
20-turn right-hand helix, no dish	a simple fixed or portable start
another one	its gain typed

SatMe derives an estimated EIRP and a suggested power to stay under the beacon (3 dB under it in SSB, 6 in CW, 10 in digital modes). It is an order of magnitude, said as such: the real check is your own signal against the beacon on the downlink. Voir au Montage opens a plan that draws the profile ("QO-100 fixe : Pluto + hélice 20 tours", "QO-100 portable : Pluto + parabole 35 cm"; nothing replaced) — the Montage catalogue has the 2.4 GHz helix and the 35 cm dish.

Safety

• Nothing transmits by itself: not at start, not from a setting, not after a reconnection. The Pluto is started at each press and stopped (oscillator off) at each release.
• PTT held by the button (or the space bar), or maintenu (latched: one click transmits, another releases — for FT8). Released by 2 s without news from the page, the time-out (1 to 10 min), the frequency becoming forbidden, and LEILA: heard, the transmission is cut at once and no new press is taken for 15 s. Esc and the red TX band stop everything.
• Dummy load first: sur charge holds the Pluto's gain at −40 dB under a red band. Every SatMe-PC start comes back to it; leaving it (on the station's PC only) asks for a confirmation, and so does the first PTT on the air.
• Cap: the highest Pluto gain, under the station's own (Réglages › Poste et rotor › ADALM-PLUTO, Gain d'émission maximal). From another machine: only with émission par le réseau autorisée. A callsign is required.
• Your signal vs the beacon: while you transmit, the panel compares your level with the beacon's when SatMe hears the downlink (an SDR dongle behind the LNB). Never louder than the beacon.
• While the Pluto transmits it does not receive, and DATV, SSTV, the I/Q correction and the IC-9700 wait (and the other way round). A missing Pluto is looked for every 5 s while the page is open; the panel says so.

A first try, step by step

1. Receive first: the downlink must be heard by another receiver (an RTL-SDR or a bladeRF behind the LNB, or a SatMe-Node), the beacon calibration on (Calage). That is what shows your own signal later.
2. Settings: your callsign in Réglages › Ma station; the Pluto's address in the SDR tab; the highest transmit gain in Réglages › Poste et rotor › ADALM-PLUTO.
3. On a dummy load: the Pluto's output (or the amplifier's) on a dummy load, sur charge ticked. Choose the profile, a mode, then try the PTT: the panel, the TX band, Esc, the time-out, closing the tab (released after 2 s). An SDR nearby, or the Pluto's output through an attenuator, shows the carrier where expected.
4. The correction: type the Pluto's error if you know it; otherwise keep it for the first carrier on the air.
5. On the helix (or the dish): untick sur charge (confirmation), low gain, CW in the CW segment, a short Touche. Find your carrier on the downlink, then measure the correction on it.
6. Raise slowly, watching your signal vs the beacon: under the beacon, always. Then SSB, then FT8 with maintenu.
7. If LEILA sounds, you were too loud: the PTT is already released; lower the gain before trying again.