tridy Posted August 31, 2017 Share Posted August 31, 2017 Hi. I am trying to analyze the signal that is going from a 2.4 Ghz RF remote control into the TV that has a USB port with a dongle connected I could find the frequency and could see in in SDR# but the signal is too weak, even if I hold the remote next to HackRF's anthenna, and sometimes it does not register the signal at all. The TV is 4 steps away and registers the signal every time. the remote has Beken BK2535 DH650QS chip in it: http://www.bekencorp.com/en/Botong.Asp?Parent_id=2&Class_id=8&Id=90 What am I doing wrong? Is there some setting that needs to be adjusted? Thanks a lot! Quote Link to comment Share on other sites More sharing options...
spongella Posted September 2, 2017 Share Posted September 2, 2017 First off, I would find the FCC Registration ID number for the remote. You have to look for that on the remote itself, perhaps there is raised lettering on the unit or a sticker somewhere, may even be inside the battery holder. Then, Google that registration number to find it in the FCC's database, go through the data to find the transmit frequency and the type of transmission such as OOK (On/Off keying). The transmission type will give you some idea of how it will appear on a waterfall. Quote Link to comment Share on other sites More sharing options...
tridy Posted September 4, 2017 Author Share Posted September 4, 2017 Thanks. I tried to find the FCC or EC registration number, but could not find it. I think I will try it with another remote control that has EC certification and uses RF 2.4GHz signal and see if I can go from there. Quote Link to comment Share on other sites More sharing options...
Cap_Sig Posted September 6, 2017 Share Posted September 6, 2017 You may also want to do your testing away from other 2.4 GHz sources. If there is an overlaying transmission from another source it could be "washing out" the TX you are trying to analyze. Do you have a brand or model of the device you are analyzing? More information would help in finding possibly the frequency, modulation type, mode of operation. Depending on devices you can actually have a transmitting device to close to the receiver were there can be a dead zone of the antennas This is however unlikely with such low powered devices being used. Quote Link to comment Share on other sites More sharing options...
tridy Posted September 7, 2017 Author Share Posted September 7, 2017 I have 3 remotes/devices that work on 2.4Ghz frequency with dongles and I have hard time registering signals with HackRF on all of them. Here is one example (not the one in the first posting): Measy RC12 remote control with keyboard and air mouse. https://fccid.io/RB8RC12 https://fccid.io/RB8RC12/Test-Report/RF-Test-Report-1868274 Frequency: : 2402-2480MHz Modulation : FSK Number of Channel : 157 Channels Frequency Separation : 0.5MHz Antenna Type : Integral Antenna Gain : 0 dBi any idea how to make HackRF registering a strong signal for that? Thanks. Quote Link to comment Share on other sites More sharing options...
Cap_Sig Posted September 7, 2017 Share Posted September 7, 2017 You might want to do some research on using the HackRF for Bluetooth. There can be some issues and things that need to be modified for it to work with Bluetooth, is my understanding of it. A device like Ubertooth One is more suited for use with Bluetooth out of the box. May want to give this a read: https://www.reddit.com/r/sdr/comments/48db0a/sniffing_bluetooth_with_hackrf/ The article describes some of your problems you mention about signal strength as well as other issues. Quote Link to comment Share on other sites More sharing options...
tridy Posted September 8, 2017 Author Share Posted September 8, 2017 Thanks. I think I have got some clues. Ubertooth One would be a nice thing to have, but it costs quite a bit (in addition to HackRF that I already have). I think I will try NRF24LU1 to start with. Maybe it will catch the signal differently. Those RF dongles that receive the signal from the remote control are really small to be able to do many manipulations, and they all work really good. Very rarely happens that a press of the button will not go through. So, there must be something that could filter out most of the noise. would that be the exact frequency, sending sync on several channels. i guess I will have to figure that out. Quote Link to comment Share on other sites More sharing options...
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