Fighting RFM 69 NACK's
Once a week I was having NACK blackout. All nodes could not send nor receive anything. Initially I was resetting everything and after some 20 minutes I was “able to fix” things. However, it was reappearing. Looked very strange. I bought very very very useful device called RTL-SDR (R820T) software digital receiver. Just in case you do not have, it is worth to buy. Yes, it is around $7 dollars from aliexpress include delivery. The device is not good for NRF since range is 24 - 1766 MgHz but for RFM it is super good. Back to my problem though, I found the noise at 429 -437 Mghz and it lasts around 20 minutes, the time “I was fixing things” previously. Huh!
You can see from the video, blackout was at the frequencies from 429 -437 Mghz
After that, I switched RFM 69 to 440 Mghz and see results. 5 transmissions!!!
The device is super useful toy!!! You can listen FM radio and other air traffic control towers.
Found later is not legal to use 440 Mghz though…
The RTL-SDR (R820T):
With this tutorial you can turn RTL-SDR (R820T) into 24 - 1766 MgHz receiver and see what happens in the air.
Hope it is helpful.
It is also possible to use this superior tool to find possible influences with other RF devices
Interesting results, and great use of RTL-SDR.
Seems like there is a lot of activity on the 433 band. Do you have any idea what it could be? Wireless headphones/speakers or a baby monitor perhaps?
like there is a lot of activity on the 433 band. Do you have any idea
really no clue. it is started like this (different zoom):
@mfalkvidd Personally I am sure it is a jammer. But I do not know it is a professional jammer of secret services or an amateur device.
@Koresh that seems likely. I can't think of a legit way to use all those constant transmissions over the entire band. It certanly doesn't adhere to any duty cycle limitation.