The Remote TCP Sink Channel plugin sends I/Q samples from the baseband via TCP/IP or a Secure WebSocket across a network to a client application.
The client application could be SDRangel using the [Remote TCP Input](../../samplesource/remotetcpinput/readme.md) plugin or an rtl_tcp compatible application.
While the plugin supports the RTL0 protocol for compatibility with older applications, the newer SDRA protocol supports the following additional features:
- Different bit depths (8, 16, 24 or 32),
- Additional settings, such as decimation, frequency offset and channel gain,
- Device settings can be sent to the client for display,
- IQ compression, using FLAC or zlib, to reduce network bandwidth,
- IQ squelch, to reduce network bandwidth when no signal is being received,
- Real-time forwarding of device/antenna position and direction to client,
- Text messaging between clients and server.
The Remote TCP Sink can support multiple clients connected simultaneously, with a user-defined maximum client limit. Clients can also have a time limit applied.
Connection details can optionally be sent to a public database at https://sdrangel.org to allow operation as a WebSDR. Public servers are viewable on the [Map Feature](../../feature/map/readme.md).
<h3>1: Frequency shift from center frequency of reception</h3>
This is the shift of the channel center frequency from the device center frequency.
This is used to select the desired part of the signal when the channel sample rate is lower than the baseband sample rate.
<h3>2: Gain</h3>
Sets a gain figure in dB that is applied to I/Q samples before transmission via TCP/IP.
This option may be useful for amplifying very small signals from SDRs with high-dynamic range (E.g. 24-bits), when the network sample bit-depth is 8-bits.
Average total power in dB relative to a +/- 1.0 amplitude signal received in the pass band.
<h3>4: Level meter in dB</h3>
- top bar (green): average value
- bottom bar (blue green): instantaneous peak value
- tip vertical bar (bright green): peak hold value
<h3>5: IQ Squelch</h3>
Check to enable IQ squelch. When IQ squelch is enabled, if the channel power falls below the specified power level (6),
the plugin will squelch (suppress) all the signal and noise in the channel,
so that it can be transmitted at a very high compression ratio, reducing network bandwidth.
This option is particularly suitable for packetised data, where the client doesn't need to receive the noise between packets.
<h3>6: IQ Squelch power level</h3>
Sets the power level in dB, below which, IQ data will be squelched.
<h3>7: IQ Squelch gate time</h3>
Sets the IQ squelch gate time. The units can be us (microseconds), ms (milliseconds) or s (seconds).
<h3>8: IQ Squelch indicator</h3>
When IQ squelch is enabled, the icon will have a green background when a signal above the power level (6) is being transmitted and a grey background when the signal is squelched.
Specifies the channel and network sample rate in samples per second. If this is different from the baseband sample rate, the baseband signal will be decimated to the specified rate.
