SimTX API v24/Packets/ReceiverSessionRequest
| Frame | {{{frame}}}, field {{{field}}}
|
|---|---|
| Member | {{{member}}}
|
| Direction | Client → server |
| Session | Receiver |
| Roles | |
| Permission | None |
| Answered by | IqStreamDescriptor |
| Defined in | |
ReceiverSessionRequest starts a receiver session. It describes the receiving station (callsign, position and antenna), the receiver's noise figure, and the frequency, bandwidth, sample rate and block size the client would like. The client sends it once, immediately after an accepted HandshakeResult on a connection with role 1 or 6.
Layout
| Field | Type | Description |
|---|---|---|
packetId |
u8 |
Always 1.
|
callsign |
UTF |
Station name shown in station lists. 1–64 characters, no control characters. |
location |
GeoPoint | Receiver position. |
antenna |
AntennaConfig | Receiving antenna. A NEC deck may be supplied. |
noiseFigureDb |
f32 |
Receiver front-end noise figure in dB, ≥ 0. Real HF receivers are typically 3–8 dB; HF reception is usually limited by external noise anyway. |
centerFreqHz |
f32 |
Centre frequency in hertz, ≥ 0. |
bandwidthHz |
f32 |
Requested filter bandwidth in hertz. |
sampleRate |
i32 |
Requested sample rate in complex samples per second, > 0. |
chunkSamples |
i32 |
Requested complex samples per block, > 0. |
soloTransmitterUuid |
UTF |
Must be empty. A non-empty value isolates one transmitter and requires the monitor.any permission; without it the connection is closed.
|
Negotiation
The server adjusts the request and reports the result in IqStreamDescriptor:
| Value | Rule |
|---|---|
| Sample rate | Requests up to 2,400,000 are clamped to 24,000–2,400,000 (narrowband). Requests above are wideband: min(request, 32,000,000). |
| Block size | Narrowband: clamped to 1,024 … min(1,200,000, rate × T), where T is 40 ms on the public clustered servers and 0.5 s on a stand-alone server. Wideband: always 16,384. |
| Bandwidth | max(50, min(request, max(24,000, rate))). A non-finite or non-positive request selects the maximum. |
Validation
Invalid values close the connection without a message. Typical mistakes are a latitude outside ±90°, a longitude outside ±180°, a negative noise figure or frequency, a non-finite float, an empty callsign, and an unknown antenna type. Server and per-IP receiver limits, and the wideband budget, are also enforced by closing the connection.
Example
A receiver called N0CALL in Budapest at 120 m, with a 10 m high dipole, 5 dB noise figure, tuned to 7.1 MHz at 48 kS/s:
01 packetId 1
00 06 4E 30 43 41 4C 4C callsign "N0CALL"
40 47 BF BB 2F EC 56 D6 latitudeDeg 47.4979
40 33 0A 4A 8C 15 4C 98 longitudeDeg 19.0402
40 5E 00 00 00 00 00 00 altitudeMeters 120.0
00 06 44 49 50 4F 4C 45 antenna type "DIPOLE"
41 20 00 00 00 00 00 00 heightMeters 10.0, azimuthDeg 0.0
00 00 00 00 00 00 00 00 feedlineLossDb 0.0, wireLengthMeters 0.0
00 00 00 00 necDeckLength 0
40 A0 00 00 noiseFigureDb 5.0
4A D8 AC C0 centerFreqHz 7100000.0
47 3B 80 00 bandwidthHz 48000.0
00 00 BB 80 sampleRate 48000
00 00 07 80 chunkSamples 1920
00 00 soloTransmitterUuid ""