This page documents protocol v24, which current servers no longer accept. See
SimTX API for v25.
MonitorBlock
| Packet ID
|
10(0x0A)
|
| Direction
|
Server → client
|
| Session
|
Control
|
| Body size
|
Variable (about 16 KiB)
|
| Permission
|
None
|
| Answered by
|
|
| Answers
|
StartMonitor
|
MonitorBlock carries a block of a monitored transmitter's signal, as requested with StartMonitor. Blocks arrive in real time until MonitorEnd or StopMonitor.
| Field |
Type |
Description
|
packetId |
u8 |
Always 10.
|
stationUuid |
UTF |
The monitored transmitter.
|
sampleRate |
i32 |
Complex samples per second: the transmitter's processing rate (its declared sample rate, at least 240,000 for WFM, at most 10,000,000).
|
n |
i32 |
Number of floats that follow, at most 262,144. Currently 4,096 (2,048 complex samples).
|
iq |
n × f32 |
Complex baseband, I and Q interleaved, centred on the carrier.
|
- Demodulate the IQ with the transmitter's modulation to hear the signal.
- Monitor blocks share the control session's output queue, which holds at most 64 packets or 8 MiB. A client that cannot keep up has its control connection closed. Read on a dedicated thread.
- A wideband transmitter produces a lot of data: 10 MS/s of complex floats is 80 MB/s. Monitor such transmitters only on a fast connection.
