Cotech weather station 36-7959 (uctech ft020/ft-0205)

[Andreas Holmberg]

Hi, I just bought a weather station from ClasOhlson in hope that I could capture the signals over 433Mhz using rtl_433. It seems though that the weather station is using an unrecognized protocol. I have tested listening to signals using rtl_433 -A and found two candidates that might be the weather station. I really don't know how to proceed from here, I haven't found any information anywhere regarding the protocol. Anyone with ideas, solutions, tips how to decode the signals to retreive actual values?

Weather station:

https://www.clasohlson.com/se/Trådlös-väderstation-med-USB/p/36-7959

Manufacturer (guessing):

http://www.uctechnologyltd.com/prod_view.aspx?TypeId=29&Id=265&FId=t3:29:3

The station captures and transmits: Temperature, humidity, wind, gust, wind direction and rain. Guessing that dew point and "feels like" are calculated by the indoor unit and not transmitted by the outdoor unit. Preassure is probably from the indoor unit as well.

Signals below captured with "rtl_433 -A"

CANDIDATE NR. 1

===========================================================

Detected OOK package    2020-04-18 11:31:39

Analyzing pulses...

Total count:   98,  width: 123.54 ms            (30886 S)

Pulse width distribution:

 [ 0] count:   69,  width:  484 us [456;516]    ( 121 S)

 [ 1] count:   29,  width:  976 us [964;988]    ( 244 S)

Gap width distribution:

 [ 0] count:   68,  width:  488 us [460;520]    ( 122 S)

 [ 1] count:   29,  width:  976 us [964;988]    ( 244 S)

Pulse period distribution:

 [ 0] count:   57,  width:  976 us [964;992]    ( 244 S)

 [ 1] count:   23,  width: 1460 us [1432;1484]  ( 365 S)

 [ 2] count:   17,  width: 1952 us [1936;1972]  ( 488 S)

Level estimates [high, low]:   8392,    208

RSSI: -2.9 dB SNR: 16.1 dB Noise: -19.0 dB

Frequency offsets [F1, F2]:   -6866,      0     (-26.2 kHz, +0.0 kHz)

Guessing modulation: Manchester coding

Attempting demodulation... short_width: 484, long_width: 0, reset_limit: 992, sync_width: 0

Use a flex decoder with -X 'n=name,m=OOK_MC_ZEROBIT,s=484,l=0,r=992'

pulse_demod_manchester_zerobit(): Analyzer Device

bitbuffer:: Number of rows: 1

[00] {127} 00 29 8a 88 38 56 b6 04 39 06 8a 53 ff f7 f6 ea

More similar results:

[00] {127} 00 29 8a 88 54 5c 26 04 39 06 3a 69 ff f7 f6 e8

[00] {127} 00 29 8a 80 52 65 f8 04 39 06 38 69 ff f7 f7 62

[00] {127} 00 29 8a 80 4a 57 ee 04 39 06 38 69 ff f7 f6 e4

[00] {127} 00 29 8a 88 42 56 2c 04 39 06 38 69 ff f7 f6 96

[00] {127} 00 29 8a 88 40 50 3e 04 39 06 38 69 ff f7 f7 36

[00] {127} 00 29 8a 88 60 92 30 04 39 06 fe 41 ff f7 f7 a8

[00] {127} 00 29 8a 88 74 92 34 04 39 06 fe 41 ff f7 f7 aa

[00] {127} 00 29 8a 88 46 7e 7c 04 39 06 fe 41 ff f7 f7 30

CANDIDATE NR. 2

===========================================================

Detected OOK package    2020-04-18 11:32:27

Analyzing pulses...

Total count:  199,  width: 253.92 ms            (63481 S)

Pulse width distribution:

 [ 0] count:  143,  width:  488 us [444;520]    ( 122 S)

 [ 1] count:   56,  width:  972 us [964;984]    ( 243 S)

Gap width distribution:

 [ 0] count:  141,  width:  484 us [460;520]    ( 121 S)

 [ 1] count:   56,  width:  976 us [964;1040]   ( 244 S)

 [ 2] count:    1,  width: 5872 us [5872;5872]  (1468 S)

Pulse period distribution:

 [ 0] count:  127,  width:  976 us [916;992]    ( 244 S)

 [ 1] count:   30,  width: 1464 us [1440;1512]  ( 366 S)

 [ 2] count:   40,  width: 1952 us [1936;1968]  ( 488 S)

 [ 3] count:    1,  width: 6852 us [6852;6852]  (1713 S)

Level estimates [high, low]:  10696,    337

RSSI: -1.9 dB SNR: 15.0 dB Noise: -16.9 dB

Frequency offsets [F1, F2]:   -6386,      0     (-24.4 kHz, +0.0 kHz)

Guessing modulation: Pulse Width Modulation with multiple packets

Attempting demodulation... short_width: 488, long_width: 972, reset_limit: 5876, sync_width: 0

Use a flex decoder with -X 'n=name,m=OOK_PWM,s=488,l=972,r=5876,g=1044,t=192,y=0'

pulse_demod_pwm(): Analyzer Device

bitbuffer:: Number of rows: 2

[00] {99} ff 97 1b 6d 57 7d dd eb 25 ff f7 ef 40

[01] {100} ff cb 8d b6 ab be ee f5 92 ff fb f7 a0

More similar results:

[00] {103} ff 97 1b b5 79 fe ee f5 fd ef ff 7e e6

[01] {104} ff cb 8d da bc ff 77 7a fe f7 ff bf 73

[00] {105} ff 97 1f 95 af ff 77 7a fe f7 ff bf 6f 80

[01] {106} ff cb 8f ca d7 ff bb bd 7f 7b ff df b7 c0

[00] {104} ff 97 1b a3 f9 fe ee f5 fd ef ff 7e f7

[01] {105} ff cb 8d d1 fc ff 77 7a fe f7 ff bf 7b 80

[00] {104} ff 97 1b ad 79 fe ee f5 fe ff ff bf 7c

[01] {105} ff cb 8d d6 bc ff 77 7a ff 7f ff df be 00