Rotators
OscarWatch can point your antenna during a pass. Configure the rotator under Settings → Rotator. Serial controllers need a COM port different from the radio (on Linux prefer a stable by-id path — Linux serial ports). Network controllers (OZ9AAR URC, SPID MD-01 / MD-02) use a TCP host and port instead. Serial protocols (GS-232, EasyComm, SPID, SAEBRTrack) can also use a TCP serial connection (for example ser2net) instead of a local COM port.
Supported controllers
| Controller | Typical hardware |
|---|---|
| GS-232 | Yaesu G-5500 and many clones |
| SPID | SPID Rot1Prog / Rot2Prog / rot2proG in SP mode (600 baud default; 1200 for Rot1Prog) |
| SPID MD-01 / MD-02 (TCP) | Native Ethernet Rot2Prog: set MOTOR CONFIGURATION to ETH and protocol to SPID ROT2; default TCP port 23. Only one client at a time. Firmware 1.2507 or later recommended. |
| EasyComm II | Controllers in EC mode: SPID, M2, and similar (try 9600 baud; some hardware uses 1200) |
| SAEBRTrack | Classic satellite tracker interfaces (BASIC Stamp, PSR-100, and similar); 9600 baud default |
| OZ9AAR URC (TCP) | Ultimate Rotator Controller over Ethernet; default TCP port 1111; set URC to REM (remote) mode so GOTO moves the antennas |
| Green Heron RT-21 Az-El | Two independent DCU-1 boards (two USB COM ports). Default 4800 baud. Select this type, not GS-232. Assign azimuth and elevation ports carefully. |
Main settings
- Connection — for serial protocols, choose Serial (COM port) or TCP serial (e.g. ser2net). Baud rate applies only to local serial; configure baud on the ser2net (or similar) server when using TCP.
- Serial port and rotator type (when Connection is Serial). On Linux, see Linux serial ports for stable paths after reboot.
- Green Heron RT-21 Az-El: plug in both USB cables. Choose this type (not GS-232). Set the azimuth and elevation COM ports separately. Default baud is 4800 (DCU-1). Default elevation range is 90°. Overlap (450°) only works if the RT-21 itself is set for overlap in the Green Heron setup utility. On Linux, prefer
by-idpaths so az/el do not swap after reboot. - TCP serial: enter host and TCP port for a raw serial tunnel. OscarWatch speaks the same protocol bytes as over COM (not URC JSON). Prefer a local network; high latency can cause timeouts.
- SPID MD-01 / MD-02 (TCP): enter the controller host (IP or hostname) and TCP port (default 23). On the controller, set MOTOR CONFIGURATION to ETH and protocol to SPID ROT2. OscarWatch uses the Rot2Prog binary protocol and reads the position reply after every set-position command. Only one TCP client can connect at a time. Firmware 1.2507 or later is recommended.
- OZ9AAR URC (TCP): enter the URC host (IP or hostname) and TCP port (default 1111). On the controller, enable the socket server and select REM / remote tracking mode. OscarWatch sends JSON
POLLandGOTOrequests; there is no separate stop command — Stop re-issues GOTO at the current position. - Interfaces without position feedback (GS-232 and EasyComm): OscarWatch only needs the COM port to open before it starts tracking. Some interfaces (for example the Foxdelta ST3) accept goto commands but never report az/el. OscarWatch asks for the position once after connecting; if nothing comes back, it stops asking until the port is reopened and the sidebar shows the last commanded az/el.
- EasyComm II: set the controller to EC (or EasyComm) mode. Default baud is 9600 when you pick this type in Settings; use 1200 if your controller manual specifies it (some SPID emulation modes).
- SAEBRTrack: select this type for PSR-100, Arduino SAEBRTrack sketches, and similar fire-and-forget rotors. Default baud is 9600. Commands are compact whole-degree
AZnnnELnnn. There is no position feedback — OscarWatch does not sendAZ/ELqueries (those would be misread as move-to-zero on many controllers). The sidebar shows the last commanded az/el instead. - SPID native mode: set the controller to SP protocol and Auto (A) on the front panel before connecting. Rot2Prog uses 600 baud. On macOS, choose the
/dev/cu.usbserial-*port rather than/dev/tty.usbserial-*, and close any other rotator application that has the port open. The controller can report azimuth below 0° (for example −86°); the sidebar shows it as the compass heading (274°). - Azimuth range — 360° or 450° (G-5500 style).
- Smart azimuth (450°) — uses 361–450° for the shortest path when the pass will actually cross 0° (north). Northbound passes that turn around east of north stay in the primary band (only shown for 450°).
- Elevation range — 0–90° standard, or 0–180° for over-the-top mounts that can track past zenith by flipping azimuth.
- Track-start elevation: tracking begins when the satellite rises above this angle (default −3°). Keyhole pre-position uses this as its floor (not below 0°).
- Movement threshold: minimum angular change before a new satellite target is sent (default 1.0°). If the controller reports az/el still outside this threshold after the rotator has stopped moving, OscarWatch re-issues the last command (pass tracking, manual Rotate, and park) so a noisy encoder that stops early will start again. While the rotator is still slewing, the same command is not sent again. Stop cancels that retry. Controllers with no position feedback (SAEBRTrack) are unchanged.
- Park azimuth / elevation: home position.
- Park rotator after pass — on by default; moves to park when the satellite drops below track-start. Uncheck to leave the beam where it finished.
- Calibration offsets — optional az/el corrections (degrees) for pass tracking and manual moves. Park uses configured park az/el exactly.
Keyhole avoidance (0–180° elevation only)
On 0–180° rotators, a high pass near zenith can outrun the rotator — the “keyhole” where azimuth swings rapidly while elevation passes through 90°. OscarWatch can analyse such passes and, when beneficial, pre-position the beam flipped (azimuth +180°, at the track-start elevation) before AOS, then track over the top instead of fighting the keyhole.
These options appear only when elevation range is 0–180°. They are hidden for 0–90° rotators.
- Enable keyhole avoidance — off by default. Sidebar may show Keyhole Avoidance during a flipped pass.
- Slew rate (°/s) — your rotator’s maximum speed; used to estimate signal-loss windows.
- Keyhole threshold (°) — minimum pass max-elevation (60–89°) before a pass is treated as keyhole (default 80°).
Pre-position slews azimuth at the track-start elevation, not below 0°. It does not use the station horizon mask.
If planning fails or the feature is off, tracking uses normal az/el commands.
Standby and manual pointing
Standby parks the rotator and pauses CAT. Use it when browsing the map. The sidebar heading changes from Live to Standby, and Resume tracking stays highlighted until you press it.
While in Standby, the menu bar shows Rotator (if rotator control is enabled). Point the beam manually without resuming tracking — handy for a quick terrestrial contact or between passes.
- Enter Azimuth and Elevation within your configured limits.
- Rotate — slew to position; Stop — halt in progress; Park — go to park.
- Close — dismiss the dialogue; beam stays put until Park or Resume.