Download SATSAGEN 0.5 and latest versions from this page:
- Works with:
- HackRF One
- RTL-SDR Dongles
- Simple Spectrum Analyzer series like D6 JTGP-1033, Simple Spectrum Analyzer, and so on.
- Video trigger, real-time trigger, and fast-cycle feature
- ADALM-PLUTO custom gain table and Extended linearization table for all devices
- Transmit from raw format files
- I/Q balance panel
- RX/TX converter offset
- Video Filter average option
- Keyboard or mouse wheel moving markers
- Status Display
- The X-Axis CT and SU indicators
Choose the device
In Settings->Devices select the device model from the Model list control.
If one or more type model selected devices are present, these will be proposed in the below Device list.
If you connect a device at this time, press the Scan button to refresh the Device list control.
In a multi-device scenario, different RX and TX device model is allowed, with the one exception that the RTL-SDR device obviously can’t act as a TX device.
Video trigger, real-time trigger, and fast-cycle feature
The Video trigger shows the spectrum graph when a signal of the minimum selected level occurs.
This is a random 4ms pulse caught by the Video trigger set at level 18. The Video level trigger is referred directly to the ADC depth value of the RX device.
The Line and Ext are real-time triggers, these start the acquisition when an external digital event occurs. With the knob select what type of digital event desire from Low, High, Chg, Neg, and Pos options.
- Low type starts the acquisition when the digital input is in a low state.
- High type starts the acquisition when the digital input in a high state.
- Chg type starts the acquisition when the digital input changes state.
- Neg type starts the acquisition at the falling edge of the input.
- Pos type starts the acquisition at the raising edge of the input.
Simple external hardware is required for the real-time triggers feature.
If a Generic serial is selected on the Trigger IN device control of Settings->EXT OUT tab, the Line trigger is mapped to DCD input of the serial specified by COM port control, and the Ext trigger is mapped to RI input of that serial COM port.
If a USB D/A albfer.com is selected on the Trigger IN device control of Settings->EXT OUT tab, the interface described on this page with FW version 2.0 can be used as a real-time input interface. The digital inputs are mapped like the above Generic serial on the USB D/A albfer.com interface, but an added feature of analog inputs can be used: the Line trigger is mapped to A0 input and the Ext trigger is mapped to A1 input. To enable this feature, click on the type title below the knob when a Line or Ext triggers are selected.
Now with the knob selects the analog level where the trigger starts the acquisition, with RE (rising edge) level or FE (falling edge) level.
To use the real-time trigger is required the Fast-Cycle set to on and the Optimize buffer size for real-time sampling checked (see on RX device controls on Settings->Devices tab).
The Line and Ext labels could be red blinking if the trigger fails to respond at the events in time.
The Cycle-Time of the acquisitions (or Sweep-Time depending on the model of the RX device) is automatically tuned by the application to minimize CPU load according to sampling rate and FFT size selected by the user.
If the Fast-Cycle feature is turned on, the Cycle-time is fixed to the maximum speed of acquisition.
More speed performance (but with more CPU load) can be reached by selecting the SA uses CPU timestamp-based timer feature located in the Settings->Extra tab.
ADALM-PLUTO custom gain table
The ADALM-PLUTO standard gain table is optimized by ADI for the best RX noise factor in the whole range of frequencies. Unfortunately, the standard gain table doesn’t work as expected for spectrum analyzer operations because of the non-linear gain of LNA and for the table that is divided into three different ranges of frequencies.
This is what happens with the standard gain table after calibration and moving from 30dB of RX gain to 31dB.
A flat frequency custom gain table is provided with the SATSAGEN distribution, it is located on the program directory as ad9361_CGT.
Add these lines to the RX linearization INI file to load the custom gain table on Pluto at the power on:
An extended RX linearization file is required to mitigate the non-linear gain of LNA in any case.
An extended RX linearization file model with the load of the custom gain table is provided on the program directory as curvecorrRX_PLUTOCGT.ini.
More information about compiling the extended RX linearization files will be published soon.
The standard gain table will be reloaded on the Pluto device at the power off of SATSAGEN to ensure the operation of other applications.
Transmit from raw format files
Open the EXT modulation panel from the menu or the EXTMOD Panel button of the Toolbar.
An only the RAW file is accepted. Specify in Format list the format to use to play the file and the sample rate according to the TX device selected capability.
If the Loop control is checked, the file will be transmitted endlessly until the stop command by the user.
The Offset DC value can be an aid to minimize the LO image residual component. Set initially to zero, check the control Apply changes to running thread and start TX streaming. During the reproduction, change the Offset DC value with the knob control until the LO image component reaches the lower position.
To start TX streaming of the file specified above, select the EXT modulation on the Generator panel and start the Generator.
The EXT label is red blinking when the thread is streaming.
I/Q balance panel
Open the I/Q balance panel with the context menu:
The Device I/Q balance panel is a tool useful to manually improve the quadrature of the RX/TX signal, especially when devices like RTL-SDR or HackRf are used.
This is the LO component of the RTL-SDR dongle before the I/Q balanced is applied.
After the right I/Q balanced is applied, the LO component is almost at -80dBm.
The values of I/Q balance will be saved on devices configuration and automatically restored when the devices are connected and used.
When the Spectrum Analyzer is running, open the Waterfall with the context menu or the Waterfall button on the new tool panel opened by the panels button.
The Min and Max controls adjust the contrast of the Waterfall according to the signal level.
Click to Info button to adding the frequency and the time information.
RX/TX converter offset
If your SDR device has a converter, it could be useful setting an offset in SATSAGEN to have a matching frequency scale and input field.
Two fields in the Settings->Devices tab can be used to specify converters offset, Converter RX and Converter TX:
When a down-converter like an LNB is connected to the RX port, it should set the Converter RX field with the LO converter’s exact frequency with a minus sign. E.g., for a converter like LNB should be -9750000 kHz.
The rule for both fields is a minus value for a down-converter and a plus value for an up-converter.
Video Filter average option
The video filter normally operates to displays each measurement’s max value for the number of times chosen by the user. To switch to the averaging video filter, click on the little Led/button VF avg over the Video filter knob control.
Keyboard or mouse wheel moving markers
After a marker is placed, it can be moved by the mouse’s wheel or by the two keys J and K. This features works either in SA and TSA operations, but to activate it should be clicking on the window scope, and the marker to move should be active firstly.
A marker was placed.
The above marker after pressing the J key three times.
The same marker after pressing the K key six times.
The status display shows some peculiar information about the active RX and TX devices. To activate this feature, click on the Status display from the context menu. For each device are displayed the type model, the attenuator value, and the converter offset value.
The X-Axis CT and SU indicators
The CT indicator shows the Cycle Time of the SA. The Cycle Time includes the sampling time, the frequency switch time if the SA is in the swept-tuned mode, the Data computation and formatting time, and finally the display update time. For the SSA devices like the Simple Spectrum Analyzer, the CT is replaced by the Sweep-Time indicator.
The SU indicator shows the percentage of use of the stream from the SDR device. In the image example above, 7,43% of the sampling stream is used to display the spectrum.