IndexError: list index out of range

[uvedhe]

I'm trying to read in wind data from my weather station into a Python script, to then be able to do some calculations with the data. I discovered WeeWX and thought this was the way to go. Now I've been trying to get the RTL Davis driver to work. I'm using an RTL-SDR v3 dongle on OS X 10.13. I can successfully run $GOPATH/bin/rtldavis which returns various entries, like these:

19:10:43.856163 Init channels: wait max 17 seconds for a message of each transmitter
19:11:01.793521 Init channels: wait max 17 seconds for a message of each transmitter
19:11:01.794049 Hop: {ChannelIdx:0 ChannelFreq:868077250 FreqError:0}
19:11:19.732536 Init channels: wait max 17 seconds for a message of each transmitter
19:11:19.732580 Hop: {ChannelIdx:0 ChannelFreq:868077250 FreqError:0}

Now I was hoping to actually get some data out, so I thought I needed to install the rtldavis driver. Install all went successfully, but when I run PYTHONPATH=bin python bin/user/rtldavis.py --cmd="/Users/user/go/bin/rtldavis" I get the error IndexError: list index out of range.

Not sure where it's going wrong?

Here's the full output:

19:03:46.160784 rtldavis.go VERSION=0.12
19:03:46.161047 tr=1 fc=0 ppm=0 gain=0 ex=0 maxmissed=51 actChan=[0] maxChan=1
19:03:46.161326 BitRate: 19200
19:03:46.161340 SymbolLength: 14
19:03:46.161347 SampleRate: 268800
19:03:46.161359 Preamble: 1100101110001001
19:03:46.161368 PreambleSymbols: 16
19:03:46.161375 PreambleLength: 224
19:03:46.161387 PacketSymbols: 80
19:03:46.161394 PacketLength: 1120
19:03:46.161405 BlockSize: 512
19:03:46.161411 BufferLength: 2048
Found Rafael Micro R820T tuner
19:03:46.610555 Hop: {ChannelIdx:0 ChannelFreq:868077250 FreqError:0}
Exact sample rate is: 268800.001367 Hz
19:03:46.814340 GetTunerGain: 0 Db
19:03:46.814362 SetFreqCorrection 0 ppm Successful
19:03:46.818456 Init channels: wait max 17 seconds for a message of each transmitter
Traceback (most recent call last):
  File "bin/user/rtldavis.py", line 1337, in <module>
    payload = lines[0].strip()
IndexError: list index out of range

[lheijst]

Hi,

I have copied your question to the weewx-rtldavis topic in the weewx-development forum. See: https://groups.google.com/forum/#!topic/weewx-development/jhGleLxu-p0%5B201-225%5D

Your will find my answer there.

Luc

[nyavlis]

uvedhe,

I've experienced this bug this morning and I've checked the code of rtldavis.py. You simply have missed your customizations in your command line when testing the driver.

rtldavis.py : There's a 10s timeout in get Queue() (for stderr). 485 line = self.stderr_queue.get(True, 10).decode('utf-8')

If the rtldavis binary GO program does not recognises any ISS, it will wait for 17 seconds and at line 1337, get_stderr times out after 10s, and lines is "null" -> list index out of range

It works when rtldavis is running well, with your custom parameters, for ex for me :

root@nulinux:/usr/share/weewx# sudo PYTHONPATH=. python user/rtldavis.py --cmd="/root/go/bin/rtldavis -tr=1 -tf="EU" -fc=4750"