A small NRF24L01 chip comparison



  • I did a really small test today.

    I used the 'Poor man's 2.4Ghz signal scanner' sketch. It uses a NRF24L01 module to scan over all channels and outputs detected signal.

    The different modules showed very different outcomes.

    The question I have for you is: what do you think the outcome means?

    The setup

    • All of them were just switched out in an Arduino Nano Wireless Expansion board. This means no problems with cables being faulty or influential.
    • All done in the same place, minutes after each other.

    The results

    Normal cheap fake Chinese NRF24 chip:

    Starting Poor Man's Wireless 2.4GHz Scanner ...
    
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
      123587655966757455132   1                                                                                                     
       2359989895968855221    1                                                                                                     
      144558798968988393221                                                                                                         
      168798898997878889763                                                                                                         
       2677568777656798422                                     2222211                                                              
       5596555588588788313                  1                  11222            1                                                   
      234668658895444644121                                    11111                                                                
      216379998769747856211                                    11111                                                                
      232467679787552441111                                    4443311                                                              
      135555678997989876211                                    1111111                                                              
      233788599996898954232                                    21111 1                                                              
      113775979888467897121                                    2221111                                                              
      125587758989898855531                                    2221111                                                              
      4656968897965768666731                                                                                                        
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
      13473956666856578541                                       1                                                                  
      113777868799744534111                                      1                                                                  
      112499646766534421111                                    1 111                                                                
         9989688988886861 1                                    56615                                                                
      223878776759888974122                                    11211                                                                
      125657977675665743321                                      2                                                                  
      113557469867769763321                                    111 1                                                                
       33658858598988964321                                     11 1                                                                
      114878689797866874211                                    111                                                                  
    

    Version with shielding:

    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
       1215966666857998343                                     121                                                                  
       1376878786977999755                1 1         1111     111            11                                                    
        2445577867769588421                                    122                                                                  
       1334667477796796662                                     221                                                                  
       1136479988777987555                                     222                                                                  
        147799989898976664                                     334                                                                  
        133758796979783211                                     335                                                                  
       1355899899798899752                                     111                                                                  
        365888878855985431           1 11  11                  333 1                                                                
        1568968776778988551                                    111                                                                  
       1267888888889998866                                     111                                                                  
       1221976859875451212                                     222                                                                  
        233877978978787332                                     433             111                                                  
       1255666757789797665                                     111                                                                  
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
       1255876988888888442                                     211                                                                  
       1244685977868765554                                     112             1                                                    
       2233677967987656433                                     222                                                                  
        127665987998876331                                     324                                                                  
       1134676899968987421                                     212             1                                                    
        145885777978896533                                     212         1                                                        
       1254665667876999873           1                         222 1                                                                
       1212565395568956161                                     211                                                                  
        285577995686978552                                     222                                                                  
       13226585857676965221                                    111                                                                  
       1145757799786786443                                     111                                                                  
       1256566669888779854                                     111                                                                  
        368999888999889996                                     111                                                                  
        255879987887688764                                     111                                                                  
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
       1377999898998987877                                     111           111                                                    
       1468899988987787774                                     111                                                                  
       2348999888686682265                                     46611           1                                                    
       3448898876668887655                                     1 1                                                                  
       3466999976798767442                                                                                                          
       1136786878897741321                                       1             1                                                    
       1115746669876995 32                                     1 1                                                                  
       23456888676989944631                                                   11                                                    
       1343769686685686642                                                                                                          
       1353476888596978443                                                    11                                                    
       35657577578979898651                                                    111                                                  
       34557698689997987851                                      1         1   1                                                    
       3558589877997776574                                     1              11                                                    
       33536788987786895651                                    11                                                                   
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
       5468968989666866541                                     1 1                                                                  
       47659988998797776452                                    112             1                                                    
       35659796978787684431                                    211             1 11                                                 
       24547766665799943541                                    212             1                                                    
       1556975769999997754                                     2 1                                                                  
       3435675787977674631                                     111                                                                  
    

    Shielded with antenna:

    Starting Poor Man's Wireless 2.4GHz Scanner ...
    
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
    111111111111111111111111111111171111111111111119111    1111111481111111111111111                                              11
    111111111111111111111111111111191111111111111 1911     1111111991111111111111111                                              11
    111111111111111111111111111111191111111111111 19111    111111199111111111111111111                                            11
    111112122222222231111111111111171111111111111 19111    1111111291111111111111111                                              11
    222222233433343343222222222211191111111111111 19111    11111115811111111111111111                                             22
    111111122222222222111111111111191111111111111 191      1111111591111111111111111                                              11
    11111111111111111111111111111116211111111111111911     111111129111111111111111111                                            11
    111111111111111111111111111111151111111111111 1911     1111111191111111111111111                                              11
    111111111111111111111111111111161111111111111 1911     11111111911111111111111111                                             11
    112222233323333332122112121111162111111111111 1911     111111119111111111111111 11                                            11
    111111122222221221111111111111181111111111111119111    1111111191111111111111111                                              11
    1111111111111111111111111111111711111111111111191      1111111191111111111111111                                              11
    111111121121111111111111111111181111111111111 19111    1111111291111111111111111                                              11
    111111122222122222111111111111161111111111111119111    1111111291111111111111111 1                                            11
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
    111111111111111111111111111111161111111111111 191      111111119111111111111111111                                            11
    1111111112211121211111111111111711111111111111191111 1111111111911111111111111111                                             11
    111111111111111111111111111111191111111111111 191      11111115811111111111111111                                             11
    1111111222222222221111111111111911111111111111191 1    11111116711111111111111111                                             11
    111111111111111211111111111111191111111111111139       1111111831111111111111111                                              11
    111111111111111211111111111111161111111111111119       11111114811111111111111111                                             11
    11111111111111111111111111111119111111111111113911     1111111781111111111111111 1                                            11
    111111132222222222111111111111191111111111111119111    1111111581111111111111111 1                                            11
    111111111111111111111111111111191111111111111119111    1111111391111111111111111 1                                            11
    111111111111111111111111111111191111111111111 19       1111111291111111111111111                                              11
    111111111211111111111111111111191111111111111 1911     1111111391111111111111111                                              11
    111111111111112221111111111111191111111111111 191      1111111491111111111111111                                              11
    111212223222223222111111111111191111111111111119111    1111111291111111111111111                                              11
    223233343343443433222222222111191111111111111 19       11111112911111111111111111                                             12
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
    111212233332222333222121111111191111111111111 19       11111113911111111111111111                                             11
    11111222323323332222211111111113111111111111117711     111111192111111111111111                                               11
    

    The EBYTE small red modules:

    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
      1111111212111111111 11        11233111111  111            49    111111111111  11                                              
     1 111111112121111111          111233111111  11             19    111111111111  11                                              
         112211223111111111   1    111122111111  111            39     11111111111   1                                              
       112122222221222211 1   11    22344111111  1111           19    111111111111  1                                               
         1111112121111111 1     1  1113331111    1111           98   1 11111111111 11                                               
         111211112111111        1   12344111111  11             99    11111111111111 1                                              
       1 111111111111111       1    1111111111   111            95    111111111211 1 1                                              
      11 111111111111111 1     1    11222111111  1111           94    111111111111 11                                               
         113333434332211     1      12444111111  111            92    111111111111                                                  
        1111111112111111  1        111444111111  1111           92    111111111111                                                  
     111 1111111111111111111 11     11221111111  1111           91     11111111211                                                  
     111 222323435332211111  111    125562111   111             9      11111111111                                                  
       111111111111111111 1  1      111211111    111            91    111111111111   1                                              
         111111111111111 11  11     11223111111  11             91    11111111121    1                                              
    0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111
    0000000001111111111222222222233333333334444444444555555555566666666667777777777888888888899999999990000000000111111111122222222
    1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
     1111112221223232122       1    11666221211  211            91    111211111211                                                  
      111111111212121111     1  1   11333111111  11             91    111111111111 1                                                
     11111111111111111111    1111   11222111111  1111           92    111111111211                                                  
     1 11111111111111111            11111111111 11111           91    1111111112111111                                              
      111111111111111111      11    11111111111 11111           91     111111113111                                                 
        1111111111111111 111 1  1   11332111111 11111           89    111111111111  11                                              
         111111111111111        1  111111111111 11111           93    111111111211 1                                                
     1  1111111111111111 1     1   111211111111  1111           91    111111111111 11                                               
     11111111111111111111     11    112221111 1  1111           94    111111111111  11                                              
        11111111121111111 11  111   11221111111 111             91   1 11111111111                                                  
       11222212424232212           11233311 1 1 11111 1         91   1 1111111121  1                                                
       111111112111211111    1 11   1122111 1    1 11           93  1 111111111211                                                  
     111 1111111121111111      1   111111111111  1111           92    11111111111  1                                                
     1111112112222221111 111    1   11322111111  1111           93    111111111111 111     
    

  • Mod

    @alowhum this method uses the received power detector function of nrf24 modules, which just scans a channel for some time. If in this time frame a 'strong' signal is detected it will count as one. It's not as fancy as RSSI for instance, and is influenced by antenna type, orientation and preamp.
    I recently did some tests and can clearly detect eg wifi activity, strongly influenced by heavy wifi traffic. Try starting a speedtest on your mobile phone while running the scan 😉
    As the spectrum changes over time comparing in detail will be hard, but wifi channels will show up clearly if you scan long enough.


  • Mod

    @alowhum By the way, I finished an extension for the nRF24Doctor about a week ago to display the nRF24 received power spectrum:

    0_1536688587355_8de2f048-1b75-44ac-bcee-87368ca7a8be-image.png

    Between channels 0 and 125 you see a little 'chart' which has a clear peak around the center. The little dot above the chart is an indicator which shows the selected channel (61), frequency (2.461GHz) and Wifi channel (11) at the bottom row.

    The peak in the chart is caused by my Wifi at channel 11 😉



  • My assumptions are:

    • More data in a line means there is more range: it picks up more signals.

    What I take from this is:

    • The version with shielding has surprisingly poor range.
    • The version with an antenna (not the PA version!) has a lot of range. But it's expensive.
    • The eByte module has a lot of range for the price.

    Other thoughts:

    • The first two pick up a signal in channel 61
    • The eByte picks up a strong signal in channel 62, later shifting to channel 61. It picks it up ridiculously strongly (a score of 9). Is it picking up its own signal perhaps?
    • Oddly enough, the antenna version seems to think the same signal is on channel 64.

  • Mod

    @alowhum said in A small NRF24L01 chip comparison:

    My assumptions are:

    • More data in a line means there is more range: it picks up more signals.

    More data in a line means this channel has higher occupation; other devices are using the same channel and you'd better choose an empty channel for your nRF network (like 85 and up).

    What I take from this is:

    • The version with shielding has surprisingly poor range.

    Doesn't make much difference I would say; it has lower sensitivity in neighbouring channels though.

    • The version with an antenna (not the PA version!) has a lot of range. But it's expensive.

    Remember, this tests receive only, so no clue on transmit range.

    • The eByte module has a lot of range for the price.

    That I knew already 😉

    Other thoughts:

    • The first two pick up a signal in channel 61

    They all do

    • The eByte picks up a strong signal in channel 62, later shifting to channel 61. It picks it up ridiculously strongly (a score of 9). Is it picking up its own signal perhaps?

    No, it's receiving only. Maybe some frequency hopping node nearby (bluetooth -- https://www.youtube.com/watch?v=6qNWQxRKoss) ? Smartwatch?

    • Oddly enough, the antenna version seems to think the same signal is on channel 64.

    These are snaphots of on-air traffic that vary over time.
    If traffic was really at channel 61 and it received at channel 64 that module would not be able to communicate with other modules at the same channel.


 

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