Network IQ export
Network IQ sends a live stream to another analysis program without first recording it.
- Add a Network IQ node.
- Connect one Device
IQoutput or one channelbasebandoutput. For multi-stream radios, choose the lane to export. A node cannot accept both source types at once. - Choose UDP or TCP, the sample encoding, and a
host:portdestination. - Start the receiving tool first, then press Start export.
The face reports the exact sample rate and center frequency to enter in the receiver, plus sent bytes, datagram/write count, capture overruns, and writer errors. The sample rate is locked while the export is active because the raw stream has no in-band rate-change message. Retuning remains available; update the receiver’s center-frequency setting after a retune.
Channel baseband uses the same format at the channel’s lower sample rate, after frequency translation and filtering. This reduces network bandwidth when another tool only needs one signal. Each channel supports one export, independently of device-wide export.
Wire contract
The payload is unframed, interleaved I, Q, I, Q, ... in one of these encodings:
| Setting | Components | Bytes per complex sample | Typical receiver type |
|---|---|---|---|
cf32_le | IEEE-754 32-bit float, little-endian | 8 | GNU Radio Complex |
ci16_le | signed 16-bit integer, little-endian | 4 | GNU Radio Short, then Interleaved Short to Complex |
cu8 | unsigned 8-bit integer, zero at 127.5 | 2 | RTL-SDR-style byte IQ |
The identifiers and byte layout follow the SigMF datatype definitions, which specify interleaved I-first complex samples. This is not itself a SigMF recording because a live stream has no SigMF metadata file; the node reports the rate and center frequency separately.
UDP uses payloads of at most 1,400 bytes, below a normal 1,500-byte Ethernet MTU after IP and
UDP headers. Each datagram contains a whole number of complex samples. There is no sequence
header, so the stream cannot reliably identify missing or reordered datagrams. sdr– reports
loss before the socket, but cannot report network delivery loss. GNU Radio’s UDP Source should use
header None, the matching data type, and a payload size of 1,400.
TCP connects outward to the destination and writes one continuous byte stream. The receiving program must be listening before export starts. TCP avoids datagram loss and reordering, but a receiver that cannot keep up eventually fills the bounded export queue; sdr– then stops the writer and reports the error.
Security
The API caller chooses the destination host and port, and an active export can send several megabits per second. Keep the server restricted to trusted callers. In particular, configure the shared token and appropriate network access controls whenever the HTTP server is reachable beyond the local desktop.
Protocol compatibility
This output is raw IQ. Configure the receiving program with the same encoding, sample rate, and centre frequency; the stream carries no timestamps, stream IDs, or radio metadata.
It is not a VITA 49 or DIFI stream. Receivers expecting either protocol need framing and context that this output does not provide.
It is also separate from rtl_tcp, which lets a client control a remote radio’s tuning, sample
rate, and gain. sdr– supports rtl_tcp as a network Device source.