2.1.6. SDR What is in the box

The following accessories and materials are included with your STEMlab SDR transceiver module.

  • SDR transceiver 160-10 10W module
  • DC power cord with Anderson Power Pole™ connector
  • 4 x SMA cable for connecting C25 module with STEMlab 125-14 and antenna
  • impedance transformer board Other additional requirements

In addition to the supplied accessories, software and cables supplied with STEMlab SDR transceiver kit, you will need to provide the following:

  • An HF-Antenna or dummy load with BNC
  • good RF ground
  • A stabilized DC 13.8 VDC, 3A Power Supply

SDR application requirements:

  • Personal computer (PC) running Windows 7 or later. Either 32 or 64-bit operating systems are supported. Start using STEMlab as Radio Station - SDR transceiver Connecting the cables



Before connecting Red Pitaya to SDR transceiver module, turn Red Pitaya off, by removing power supply cable.

  1. connect Tx of SDR transciver module to Red Pitaya OUT1
  2. connect Rx of SDR ransciver module to Red Pitaya IN1 (notice this cable has a transformer)
  3. connect control cable from SDR transceiver to Red Pitaya

identify pin with arrow and connect the cable as on the image bellow.

  1. Make sure jumper is set as shown on image above.
  2. Make sure your SD card is still inserted
  3. Make sure your ethernet cable is still plugged in
  4. Connect power supply 5V 2A to turn Red Pitaya back on.
  5. Connect antenna
  6. Connect SDR transceiver to 13.8V 3A power supply


STEMlab SDR transceiver module should be powered by DC 13.8V Power Supply that can provide at least 3 A of constant power. Make sure that is turned off and then use DC power cord with Anderson Power Pole™ connector (9) to connect it with module. RED wire is positive (+) while BLACK wire is negative (-), double check to not mix the colours or polarity!

  1. Turn on 13.8V power supply Power SDR installation and SDR configuration

Click here to download Power SDR installation package.

  1. Start the installation by double clicking on the Setup_PowerSDR_STEMlab_HAMlab_Edition.exe file.

  2. If you are asked for extended user access rights during the installation click Yes! Running installer with administration rights will work as well.


On Windows 10 you might get warning of Unknown Publisher you can procede with installation by clicking on “more info” and then “Run anyway”.

../../../_images/PowerSDRinstallation3.PNG ../../../_images/PowerSDRinstallation4.PNG
  1. Follow the instructions of the setup routine and accept the license agreements if asked for.

    ../../../_images/Capture1.PNG ../../../_images/Capture2.PNG ../../../_images/Capture3.PNG ../../../_images/Capture4.PNG ../../../_images/Capture5.PNG ../../../_images/Capture6.PNG ../../../_images/Capture7.PNG ../../../_images/Capture8.PNG
  2. At the end of the installation you are asked if you want to run PowerSDR software immediately, feel free to do so.

  3. PowerSDR software will start with the calculation of the FFT wisdom file, which will take a while depending on the CPU power of your computer. This is only done once, even after updating the software to a new version in the future:

  4. After starting the PowerSDR software you will be led through the PowerSDR software specific setup wizard which lets you configure the software to use it with your STEMlab. Pick the HAMlab/STEMlab radio model.

  5. Select the region where you are using your STEMlab, this is important due to the different frequency ranges your are allowed to transmit in the different countries all over the world:

  6. Your initial setup is completed click finish.

  7. Click Power to connect Power SDR with STEMlab. On the screen the input singnal should appear.

    ../../../_images/Capture20.PNG General Specifications

Antenna Connector: ANT1 and ANT2 available on SMA connectors Included one cable with SMA to SO-239 UHF
Antenna Impedance: 50 Ohm Unbalanced
RF Output Power: up to 10 W CW and SSB at 13.8 V input voltage (max. 15 V)
Maximum Interconnect Cable Length Ethernet: 100 meters (328 feet), Category 5 cable
Power connector: PowerPole
../../../_images/SDRBlockDiagram.PNG Receiver Specifications

Architecture: Direct Digital Sampling
ADC Sampling Rate: 125Msps
ADC Resolution: 14 bits
Wideband Frequency Coverage: 25 kHz - 62.25 MHz
MDS (min. detectable signal): MDS (typ)@ 500Hz BW
Preamp OFF at 14MHz -113dBm
Preamp +15dB at 14MHz -130dBm
Preamp +30dB at 50MHz -135dBm
  More MDS measurements.
Preselectors: Available as add-on module (comming soon)
  User can also connect own preselectors/filters Transmitter Specifications

Architecture: Direct Digital Up-conversion
TX DAC Sampling Rate: 125 Msps
TX DAC Resolution: 14 bits
RF Output Power: up to 10 W CW and SSB at @ 13.8 V input voltage (max. 15 V)
Transmitter Frequency Range: 160 - 10 m (amateur bands only)*
Low Pass PA Filter Bands: 160m / 80 m / 40 m / 30m / 20 m / 17m / 15m / 12m / 10m / 6 m
  (possibility to changed it to any range 1.8 - 50 MHz)
Emission Modes Types: A1A (CWU, CWL), J3E (USB, LSB), A3E (AM), F3E (FM), DIGITAL (DIGU, DIGL)
Harmonic Radiation: better than -45 dB
3rd-Order IMD: better than -35 dB below PEP @ 14.2 MHz 10 Watts PEP
Cooling: copper heat spreader


C25 also supports 6m operation and has all necessary output filters for 6m, anyhow STEMlab 125-14 ouput signal is not pure enough to comply harmonic regulations for 6m