SimTX Guide/Receiving
The Receive tab starts a receiver on the server and passes its signal to an SDR program on your computer through a bridge. The setup is on the left; the Bridges list is on the right.
Receive a signal
- Under Where you listen, choose where the receiver is.
- Under Tuning, set the Center frequency and the Sample rate (Hz).
- Press Start RX.
- In your SDR program, connect an rtl_tcp source to the address shown under Bridge, by default
127.0.0.1:1234.
How to receive shows the settings in SDR++, and the SDR Console guide in SDR Console.
Where you listen
| Choice | Receiver | Needs |
|---|---|---|
| My station | One of your stations: choose it under Receive at, with its Antenna and Radio. | Sign-in |
| Public station | Another account's public station. Search under Find a public station and select it. The session uses the station's main antenna. | Sign-in |
| Ad-hoc | Any location, with a Callsign and Antenna of your own. | Nothing |
For Ad-hoc, type the Latitude and Longitude or press Pick location on map. Antenna details sets the antenna's length, Height (m), Azimuth (°) and Feedline loss (dB).
Receive here in a station's details in the Stations tab chooses that station. On your own station, Track a satellite and the Rotator work as for transmitting; see Rotators and tracking.
Tuning
| Field | Meaning |
|---|---|
| Center frequency | The middle of the band you receive. |
| Sample rate (Hz) | The width of the band, in samples per second. 250,000 suits shortwave; FM broadcast needs about 1,024,000 or more. |
Tune RX next to a transmission in a station's details sets the center frequency to it.
Bridge
| Field | Meaning |
|---|---|
| Label | A name for the bridge in the Bridges list. |
| Listen address | Where your SDR program connects. 127.0.0.1 is this computer only. 0.0.0.0 lets other computers on your network connect, and anyone there can retune it.
|
| rtl_tcp port | The port your SDR program connects to. Default 1234. |
| Hardware profile | The RTL-SDR model the bridge presents to your SDR program. Default Generic R820T. |
| Timestamped role | Adds a timestamp to each block of samples. Your SDR program gets the same samples. |
| Digital AGC | Starts the bridge with digital automatic gain control. On by default. |
Link resilience
Smooth over network dropouts adds a jitter buffer, retries and concealment of short dropouts. It is on by default. Advanced tuning sets:
| Field | Default |
|---|---|
| Read timeout (ms) | 5000 |
| Max retries | 3, or -1 for no limit |
| Retry base delay (ms) | 250 |
| Jitter buffer (ms) | 150, or -1 for off |
| Narrow upstream on repeated stalls | Lowers the sample rate when the link keeps stalling. |
Bridges
Each Start RX adds a bridge to the list, with its frequency, sample rate, address and state: Starting, Running, or ended. A line of link figures appears after trouble: reconnects, underruns, concealed blocks, narrowing and dropped blocks.
- Stop ends one bridge, Stop all every bridge after you confirm.
- Clear finished removes ended bridges.
Presets
Presets at the top saves and loads complete receive setups, the same way as on the Transmit tab.