Change nRF51DK BLE RX frequency channel (BLE sniffer)

[jrx07]

Hello,

I'm currently using the nRF51DK with Wireshark as a BLE advertisement sniffer. So far this setup has worked great, but I'd like to make a small modification for development/evaluation purposes. I want to get an accurate sense of the packet error rate, however, my lab has a lot of interference in the existing BLE advertising and WiFi channels. Using a spectrum analyzer, I found a less-noisy frequency range within the 2.4 GHz ISM band.  My hope is to change the FREQUENCY register so that I can "listen" to BLE advertising packets at a different frequency (e.g. program the nRF51DK to think it's listening for CH39 advertising packets at 2.483 GHz instead of 2.480 GHz).

Question: Is it possible for me to change the receive frequency of nRF51DK and still use the BLE sniffer code with Wireshark?

It seems like this may be possible in the Python code provided in the "extcap" folder, but any tips would be much appreciated.

Thanks for your help!

[AndreasF]

Hi.

Question: Is it possible for me to change the receive frequency of nRF51DK and still use the BLE sniffer code with Wireshark?

 I'm unsure if this will work, we don't have any support for our Python implementations. CH39 advertises at 2.480 GHz, I don’t think you can make it advertise at 2.483 GHz since that is out of BLE spec.

What i would recommend you to do if you want to avoid interference is either test at a remote location where you don't have interference from BLE/WiFi, or use a radio chamber, or find an old microwave oven which you drill a hole in to plug the USB cables inside. Microwaves have good interference reduction.

Note also that the nRF51 does work perfect as a BLE Sniffer, it is reasonable. The nRF51 also turns off and on the radio in order to recalibrate the crystal, so this should also be taken into account.

I would recommend that you use a professional BLE Sniffer, for example the Ellisys Bluetooth Explorer.

Best regards,

Andreas