Tuning Tool

tune.py is the primary user-facing tool for operating the SkyWalker-1 as a satellite receiver. It handles the complete signal chain: powering the demodulator, configuring LNB voltage and tone, sending DiSEqC switch commands, tuning to a transponder, monitoring signal quality, and capturing MPEG-2 transport stream data.

pip install pyusb

Subcommands

Subcommand	Purpose
status	Show device config, firmware version, and signal info
tune	Tune to a transponder frequency
stream	Capture MPEG-2 transport stream data
diseqc	Send DiSEqC switch commands
lnb	Control LNB voltage and 22 kHz tone

Running with no subcommand defaults to status.

Global Options

Flag	Description
-v, --verbose	Show raw USB control transfer traffic
--json	Output machine-readable JSON (where supported)

---

status — Device Information

Displays the current device state: firmware version, configuration status flags, signal lock, and SNR.

sudo python3 tools/tune.py status

Genpix SkyWalker-1 Status
==================================================

USB: Bus 1 Addr 12 (VID 0x09C0, PID 0x0203)
FW:  2.06.4 (built 2007-07-13)

Config: 0x07
  [ ON] 8PSK Started
  [ ON] BCM4500 FW Loaded
  [ ON] LNB Power On
  [off] DVB Mode
  [off] 22 kHz Tone
  [off] 18V Selected
  [off] DC Tuned
  [off] Armed (streaming)

Signal Lock: LOCKED
SNR:         8.2 dB (raw 0x0823)
Quality:     [################------------------------] 42.3%

Use --json for programmatic access to all fields.

---

tune — Transponder Tuning

The 8-step tuning sequence: check status, boot demodulator, enable LNB power, set voltage (polarization), set extra voltage, set 22 kHz tone (band), send TUNE_8PSK command, wait for signal lock.

Required Arguments

Argument	Description
FREQ	Transponder downlink frequency in MHz (e.g., 12520)
SR	Symbol rate in ksps (e.g., 27500)

Options

Flag	Description
--pol H/V/L/R	Polarization: H (horizontal/18V), V (vertical/13V), L (left circular/18V), R (right circular/13V)
--band low/high	LNB band: low (tone off, 9750 MHz LO) or high (tone on, 10600 MHz LO)
--lnb-lo MHZ	Override LNB local oscillator frequency (default: 9750 low, 10600 high)
--mod TYPE	Modulation type (default: qpsk)
--fec RATE	FEC rate (default: auto)
--timeout SECONDS	Signal lock timeout (default: 10)
--extra-volt	Enable +1V LNB voltage boost for long cables
--json	Output JSON result

Modulation Types

Name	Description	FEC Group
qpsk	DVB-S QPSK	dvbs
turbo-qpsk	Turbo-coded QPSK	turbo
turbo-8psk	Turbo-coded 8PSK	turbo
turbo-16qam	Turbo-coded 16QAM	turbo-16qam
dcii-combo	Digicipher II Combo	dcii
dcii-i	Digicipher II I-stream	dcii
dcii-q	Digicipher II Q-stream	dcii
dcii-oqpsk	Digicipher II Offset QPSK	dcii
dss	DSS QPSK	dvbs
bpsk	DVB BPSK	dvbs

FEC Rates by Group

Group	Available Rates
dvbs	1/2, 2/3, 3/4, 5/6, 7/8, auto, none
turbo	1/2, 2/3, 3/4, 5/6, auto
turbo-16qam	3/4, auto
dcii	1/2, 2/3, 6/7, 3/4, 5/11, 1/2+, 2/3+, 6/7+, 3/4+, auto

DVB-S

Standard DVB-S QPSK, Ku-band high

sudo python3 tools/tune.py tune 12520 27500 --pol H --band high

DVB-S with explicit FEC

sudo python3 tools/tune.py tune 11836 27500 --pol V --band low --fec 3/4

C-band with custom LNB LO

sudo python3 tools/tune.py tune 3960 26667 --pol V --lnb-lo 5150

Turbo

Turbo 8PSK

sudo python3 tools/tune.py tune 12224 20000 --pol V --band high --mod turbo-8psk --fec 2/3

Turbo QPSK with auto FEC

sudo python3 tools/tune.py tune 12090 20000 --pol H --band high --mod turbo-qpsk

DCII

Digicipher II Combo

sudo python3 tools/tune.py tune 12224 20000 --pol V --band high --mod dcii-combo --fec auto

DCII Split I-stream

sudo python3 tools/tune.py tune 12224 20000 --pol V --band high --mod dcii-i --fec 6/7

Tuning Output

Tuning SkyWalker-1
==================================================
  Downlink:     12520 MHz
  LNB LO:       10600 MHz
  IF Frequency:  1920.0 MHz (1920000 kHz)
  Symbol Rate:   27500 ksps (27500000 sps)
  Modulation:    DVB-S QPSK (index 0)
  FEC:           auto (index 5)
  Polarization:  Horizontal (18V)
  Band:          high (22kHz on)

[1/8] Config status: 0x07
[2/8] Demodulator already running
[3/8] LNB power already on
[4/8] Setting LNB voltage: 18V
[5/8] Extra voltage: off
[6/8] 22 kHz tone: ON
[7/8] Sending TUNE_8PSK...
[8/8] Waiting for signal lock (timeout 10s)...
...

  LOCKED
  SNR:     8.2 dB (raw 0x0823)
  Quality: [################------------------------] 42.3%

Tip

The IF frequency is computed as downlink - LNB_LO. It must fall within 950—2150 MHz or the tool will warn. If you see negative IF values, your LNB LO is set higher than the downlink frequency — check your LNB type.

---

stream — Transport Stream Capture

Captures MPEG-2 transport stream data from EP2 bulk endpoint after the device is tuned and locked. Requires a prior successful tune command (signal must be locked).

Capture to file for 60 seconds

sudo python3 tools/tune.py stream -o capture.ts --duration 60

Pipe directly to VLC

sudo python3 tools/tune.py stream --stdout | vlc -

Pipe to ffmpeg for recording

sudo python3 tools/tune.py stream --stdout | ffmpeg -i pipe: -c copy output.mp4

Flag	Description
-o, --output FILE	Write TS data to file
--stdout	Write TS data to stdout (for piping)
--duration SECONDS	Capture duration (default: until Ctrl-C)

The stream status is written to stderr when using --stdout, so it does not contaminate the TS data pipe.

Tip

Capture a short sample and analyze it with ts_analyze.py to verify PIDs, check for continuity errors, and identify the programs in the transport stream.

---

diseqc — Switch Commands

Send DiSEqC 1.0 port selection, mini-DiSEqC tone bursts, or raw DiSEqC messages.

Select DiSEqC 1.0 port 1

sudo python3 tools/tune.py diseqc --port 1

Send tone burst A

sudo python3 tools/tune.py diseqc --tone-burst A

Send raw DiSEqC message

sudo python3 tools/tune.py diseqc --raw E0 10 38 F0

Flag	Description
--port 1-4	DiSEqC 1.0 committed switch port
--tone-burst A/B	Mini-DiSEqC tone burst
--raw HH HH ...	Raw DiSEqC bytes in hex (3—6 bytes)

For details on the DiSEqC signaling implementation, see DiSEqC Protocol.

---

lnb — LNB Control

Direct control of LNB voltage, 22 kHz tone, and power supply. Running with no flags shows the current LNB state.

Show LNB status

sudo python3 tools/tune.py lnb

Set voltage and tone

sudo python3 tools/tune.py lnb --voltage 18 --tone on

Power cycle the LNB

sudo python3 tools/tune.py lnb --power off
sudo python3 tools/tune.py lnb --power on

Flag	Description
--voltage 13/18	LNB voltage (13V = vertical, 18V = horizontal)
--tone on/off	22 kHz tone (on = high band, off = low band)
--extra-volt	Enable +1V boost (13V becomes 14V, 18V becomes 19V)
--power on/off	LNB power supply on/off

Caution

The LNB can supply up to 750 mA non-continuous, but sustained loads should stay below 450 mA to avoid overheating the on-board regulator. Use --extra-volt only when needed for long cable runs.

---

Signal Quality Metrics

Metric	Source	Description
SNR	GET_SIGNAL_STRENGTH (0x87)	Signal-to-noise ratio in dB, read as 16-bit value (dBu * 256 units)
Lock	GET_SIGNAL_LOCK (0x90)	BCM4500 register 0xA4, bit 5 indicates signal lock
Quality %	Computed	SNR scaled: snr_raw * 17 maps to 0—100%, saturating at SNR >= 0x0F00

For details on the signal monitoring protocol, see Signal Monitoring.

See Also

• Tuning Protocol — firmware-level TUNE_8PSK command format
• LNB Control — hardware-level voltage and tone control
• TS Analyzer — analyze captured transport streams
• Vendor Commands — complete USB command reference