EEVblog Electronics Community Forum
Electronics => RF, Microwave, Ham Radio => Topic started by: mpradio on September 06, 2021, 09:02:55 pm
-
Hi I would like to use a PCI wifi board (Ubuntu OS) to experiment with microwave signals. I would like to be able to access the board through the software driver and be able to turn on or turn off the carriers of the Wi-Fi channels without modulation. In other words, use the board as a microwave signal generator in the Wi-Fi band (2400Mhz-2500Mhz). I have no idea where to look for information to achieve this if at all possible. Basically I would like to be able to access the records of the chip of the wifi board by looking at its data sheet (if there is this possibility).
-
You're probably looking for a software defined radio board, not a wifi card, and unless you want to spend a lot it will have a USB rather than PCIe interface. Something like the HackRF (https://greatscottgadgets.com/hackrf/one/).
Wifi chipsets do have CW test modes for compliance testing and factory use, but only the manufacturer will know how to activate them and they don't publicise that information.
If you look at MCUs with built-in wifi though, the test software is more likely to be publically available. E.g. for a very cheap signal generator you could use an Espressif ESP32 dev board and run the RF test firmware available here (https://www.espressif.com/en/support/download/other-tools). It should be able to do constant-carrier at selected frequencies in the 2.4-2.5GHz range, although you may not have a great deal of control.
-
If you can find sample code for a radio test, you may be able to put the radio into compliance test mode. For a Bluetooth radio, you can turn a signal on/off, CW/modulated, set power level, set data speed, etc., on a selected channel. Typically, this would be example code for the chip you're working with. I've never done this on WiFi, however.
Keep in mind that when you are transmitting, you should be in a screen room or RF test box to avoid radiated signals.
-
If you're want just enable/disable carrier, then you're needs RF generator and use USB or Ethernet to control it from PC.
If you're want more (for example transmit and receive signals), then you will needs more complicated setup. You can try ADALM Pluto (https://www.analog.com/en/design-center/evaluation-hardware-and-software/evaluation-boards-kits/adalm-pluto.html). But wifi needs to deal with a very wide bandwidth 40 MHz and more, so probably it cannot cover all cases. But at least it will be the most cheap and easy startup for transmit and receive signals on 2.4 GHz
-
Raspberry Pi 3+ and 4 support using the onboard Wifi as a SDR.
https://github.com/seemoo-lab/nexmon