Topic: Receiving Davis Vantage weather data with a RTL-SDR dongle

[lui]

I tried modified version of rtldavis and getting some data from my station. Would be great if it will work some day.

[Lucas]

Just try the rtldavis program with your frequencies. Then you will know what I mean.

[lui]

Is that output good?

20:24:41.375016 TRANSMITTER 0 SEEN
20:24:41.376999 Hop: {ChannelIdx:2 ChannelFreq:868360000 FreqError:-11307}
20:24:43.936956 5006C1FF7300EA68 2 0 0 0 0 msg.ID=0
20:24:43.937267 Hop: {ChannelIdx:4 ChannelFreq:868603000 FreqError:-11074}
20:24:46.500670 4006B70001003458 3 0 0 0 0 msg.ID=0
20:24:46.500978 Hop: {ChannelIdx:1 ChannelFreq:868238000 FreqError:-8901}
20:24:49.062644 8005B28E0100F8A4 4 0 0 0 0 msg.ID=0
20:24:49.062956 Hop: {ChannelIdx:3 ChannelFreq:868490800 FreqError:-9375}
20:24:51.624519 E004B5460300B5F4 5 0 0 0 0 msg.ID=0
20:24:51.624850 Hop: {ChannelIdx:0 ChannelFreq:868118000 FreqError:-7641}
20:24:54.188440 5004BAFF710094E3 6 0 0 0 0 msg.ID=0
20:24:54.188736 Hop: {ChannelIdx:2 ChannelFreq:868360000 FreqError:-7035}
20:24:56.750544 duplicate packet: 5004BAFF710094E3
20:24:56.814898 ID:0 packet missed (1)
20:24:56.815183 Hop: {ChannelIdx:4 ChannelFreq:868603000 FreqError:-5848}
20:24:59.312580 9003B90C030AA3A8 7 0 0 0 0 msg.ID=0
20:24:59.313780 Hop: {ChannelIdx:1 ChannelFreq:868238000 FreqError:-11067}
20:25:01.875945 8003B98E03004D5C 8 0 0 0 0 msg.ID=0
20:25:01.876368 Hop: {ChannelIdx:3 ChannelFreq:868490800 FreqError:-10482}
20:25:04.438088 E004BD4603003037 9 0 0 0 0 msg.ID=0
20:25:04.438413 Hop: {ChannelIdx:0 ChannelFreq:868118000 FreqError:-8013}
20:25:07.002012 5006ACFF7100EC5E 10 0 0 0 0 msg.ID=0
20:25:07.002317 Hop: {ChannelIdx:2 ChannelFreq:868360000 FreqError:-11009}
20:25:09.563924 C007B20B71000EC4 11 0 0 0 0 msg.ID=0
20:25:09.564230 Hop: {ChannelIdx:4 ChannelFreq:868603000 FreqError:-9363}
20:25:12.125514 8005B78E010044E1 12 0 0 0 0 msg.ID=0
20:25:12.126687 Hop: {ChannelIdx:1 ChannelFreq:868238000 FreqError:-5994}
20:25:14.689551 duplicate packet: 8005B78E010044E1
20:25:14.752289 ID:0 packet missed (1)
20:25:14.752580 Hop: {ChannelIdx:3 ChannelFreq:868490800 FreqError:-10641}

[Lucas]

Hi Lui,

Yes, this is the normal logging. A 'packet missed' percentage of 10-15 percent of the total to be received messages is normal.
With only one transmitter active the percentage of missed messages will be lower.

Program weewx (with the weewx-rtld driver installed), will run rtldavis, parse the raw messages and store the parsed data in the weewx datbase.
For weewx-rtld see: https://github.com/lheijst/weewx-rtld

Luc

[kobuki]

It's worth noting that the real discussion is going on in the following threads, for anyone interested:

https://groups.google.com/forum/#!topic/weewx-development/jhGleLxu-p0
https://groups.google.com/forum/#!topic/weewx-user/ZjDVbSmwmZY

[mcrossley]

My 2p worth, I found the US frequencies matched the Auruido code values almost exactly using my offset corrected RTL dongle - which is also very temperature sensitive! I have to leave it running for some time to stabilise.

There is also a fair bit of variation between different transmitters, I did not record the frequency offsets sadly. The VP2 consoles also vary, Davis "tune" each one with an offset value, I have tweaked this console offset to match my console to my ISS better.

[kobuki]

My 2p worth, I found the US frequencies matched the Auruido code values almost exactly using my offset corrected RTL dongle - which is also very temperature sensitive! I have to leave it running for some time to stabilise.

Yes - for me too. There's a bug in the original demodulator code that breaks the frequency settings somehow. Luc is trying to find that.

[Storm017]

Luc

The updated rtldavis program (US Frequencies) works.  Been capturing and displaying valid data for over a week now.

Thanks

[Lucas]

Good to hear, Rich!

My thanks goes also to you for testing the driver with the US frequencies.

Luc

[amino1958]

This may be a dated question, but I am just getting started ..... would this hardware work:

https://www.amazon.com/dp/B0129EBDS2/ref=as_li_ss_tl?ie=UTF8&linkCode=sl1&tag=rsv0f-20&linkId=9806dfa291f74f7cdb49e2cfbe3d34eb

or

https://www.ebay.com/itm/272411458376?mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5338814417&customid=&toolid=20012&mkevt=1

If not, any recommendations?
Thanks!

[Storm017]

This may be a dated question, but I am just getting started ..... would this hardware work:

https://www.amazon.com/dp/B0129EBDS2/ref=as_li_ss_tl?ie=UTF8&linkCode=sl1&tag=rsv0f-20&linkId=9806dfa291f74f7cdb49e2cfbe3d34eb

or

https://www.ebay.com/itm/272411458376?mkcid=1&mkrid=711-53200-19255-0&siteid=0&campid=5338814417&customid=&toolid=20012&mkevt=1

If not, any recommendations?
Thanks!

The RTL-SDR V.3 will work fine.

[Storm017]

If you decided to go down this route you would need a sensor for pressure, indoor temp, and indoor humidity, since you only receive data from the ISS.  The sensor I use is a BME 280: https://www.amazon.com/Adafruit-BME280-Temperature-Humidity-Pressure/dp/B013W1AJUY. 

[amino1958]

Thank you for the information. Yes, I am aware of the fact that these three sensors are in the console and not in the ISS. I don't really need the indoor sensor data and the BP is not that important to me. In fact to "fill in the gap" I may just get it from the NWS. What I am most interested in is the 2 second wind updates.
BTW... I did try this a couple of years ago using a RFM69 and a PIC with mixed results. I could receive the packets from the ISS okay as long as the ISS was about 10ft or less from the RFM69. What I need is a similar solution that has a range that is close to or exceeds the range of the Davis setup with the Console and ISS. Currently I get about 500ft LOS which is pretty good.
If I may ask, what range are you getting with the SDR and ISS?
Thank you.
 

[kobuki]

If you're looking for a proven and reliable solution for RFM69, I suggest looking at my receiver and the compatible driver - note that it currently has problems with the US band but I'm currently working on stabilizing it. It has support for internal sensors as well, like the BMP380 and others. EU/UK bands work very good and stable. Using an SDR stick also works but I have no info on its reliability. It has a driver for WeeWx, too.

[Storm017]

Thank you for the information. Yes, I am aware of the fact that these three sensors are in the console and not in the ISS. I don't really need the indoor sensor data and the BP is not that important to me. In fact to "fill in the gap" I may just get it from the NWS. What I am most interested in is the 2 second wind updates.
BTW... I did try this a couple of years ago using a RFM69 and a PIC with mixed results. I could receive the packets from the ISS okay as long as the ISS was about 10ft or less from the RFM69. What I need is a similar solution that has a range that is close to or exceeds the range of the Davis setup with the Console and ISS. Currently I get about 500ft LOS which is pretty good.
If I may ask, what range are you getting with the SDR and ISS?
Thank you.
 

The distance between the ISS and SDR is approximately 200 feet and receive packets without any issues.  This SDR been receiving ISS data without any issues since April 2019.

Code: [Select]

Nov 13 11:15:15 DavisSDR weewx[591]: rtldavis: new_archive_record
Nov 13 11:15:15 DavisSDR weewx[591]: rtldavis: ARCHIVE_STATS: last time: last_cnt[0-3]:   1636819815     5282        0        0        0
Nov 13 11:15:15 DavisSDR weewx[591]: rtldavis: ARCHIVE_STATS: curr time: curr_cnt[0-3]:   1636820115     5398        0        0        0
Nov 13 11:15:15 DavisSDR weewx[591]: rtldavis: ARCHIVE_STATS: total_max_count=117 total_count=116 total_missed=1  pctGood= 99.15
Nov 13 11:15:15 DavisSDR weewx[591]: rtldavis: ARCHIVE_STATS: station 1: max_count=  117 count= 116 missed=   1 pct_good= 99.15
If I may ask, what are you trying to accomplish?

[amino1958]

Sure...  I am helping a non-profit Environmental Preservation organization obtain some data from sensors (water depth, temperature, flow, PH, turbidity, etc.) installed at a local lake here in Orlando (Lake Cane Restoration Society LCRS - https://luckyslakeswim.com/). The data from the sensors are picked up wirelessly with an XBEE 900MHz Receiver hooked to  a Linux Box and then sent to a MQTT server for live updates and a mySQL server for archival storage. We also have  Wireless Vantage Pro 2 for other atmospheric data that we need - especially rainfall and wind. For various reasons I would like to eliminate having to use the Davis Console/Envoy with the ISS. I would rather have the ISS sensor data come directly into our Linux box as it will be easier to integrate with the rest of the sensor data. I did a similar setup where we had a cabled Vantage Pro instead of a wireless one. The interface was a breeze since the Console port on the cabled ISS PCB is RS485 and puts out the same 8 bytes of sensor data every 2 seconds just like the wireless ISS does. So I already have the code for that part taken care of. I now just need to do the same with the wireless ISS. I gave up after my RFM69 disappointment. But now seeing you guys discuss the SDR method has sparked my interest again. I have a lot to learn so I appreciate and am encouraged by the response I have been getting.
Thanks again
     

[kobuki]

I gave up after my RFM69 disappointment.   

Don't. Besides the RFM69 being used in multiple commercial products for the same purpose, there are free solutions available like mine or mcrossley's. So it does work and works very well. I still consider the SDR receiver for Davis stations a working experiment, knowing the history of the current solution. In any case, it's your call. If you feel adventurous or willing to experiment some more, you can have a lot of fun.

[amino1958]

If you're looking for a proven and reliable solution for RFM69, I suggest looking at my receiver and the compatible driver - note that it currently has problems with the US band but I'm currently working on stabilizing it. It has support for internal sensors as well, like the BMP380 and others. EU/UK bands work very good and stable. Using an SDR stick also works but I have no info on its reliability. It has a driver for WeeWx, too.

Very Cool. In retrospect I think the specific RFM69 module I was using may have been the culprit (Though I put-together two of them and both of them had range issues).
I'd love to reexplore using the RFM69 again if the SDR solution does not work. I'm not too familiar with the Arduino and do most of my embedded stuff with a PIC. But it does not look too difficult to figure out.
Thanks  for the links

[kobuki]

If you go that route sometime, using the Arduino framework is easy - if you're experienced with the PIC families, it won't pose a huge difficulty, more like getting to know a few more tools. The framework covers a lot of MCUs, it has been ported to many PIC variants, too. The code is basically plug and play with some settings in code before compilation.

[amino1958]

I gave up after my RFM69 disappointment.   

Don't. Besides the RFM69 being used in multiple commercial products for the same purpose, there are free solutions available like mine or mcrossley's. So it does work and works very well. I still consider the SDR receiver for Davis stations a working experiment, knowing the history of the current solution. In any case, it's your call. If you feel adventurous or willing to experiment some more, you can have a lot of fun.

Do you mind telling me exactly what hardware you used for your project? I'd sure like to try it out Verbatim using the same hardware as you did to see if the range issue is resolved. It still bother's me that I came so close and could not use it and would like to know why for sure!
 
Thanks!

[kobuki]

Do you mind telling me exactly what hardware you used for your project? I'd sure like to try it out Verbatim using the same hardware as you did to see if the range issue is resolved. It still bother's me that I came so close and could not use it and would like to know why for sure!

Sure, but if you look at the full repo in my first link, you'll see that I'm using a Moteino + RFM69 module. That's all it basically requires, and you can hook up a BMP380 or similar module for internal sensors if you want. Note that I haven't sorted out the US band yet (it was hindered by the lack of a US transmitter that I do have now, finally) - it means that you need some freq. tweaking to make it 100% work, otherwise it skips about every other packet. Here on the EU band, one transmitter through 2 thick walls, about 30m (~100ft), another in the attic, through 2 ceilings, about 6-7m (~20ft), I get 98-99% good packets.

[amino1958]

Thanks I'll take a look.

[Storm017]

Sure...  I am helping a non-profit Environmental Preservation organization obtain some data from sensors (water depth, temperature, flow, PH, turbidity, etc.) installed at a local lake here in Orlando

Nice, sounds interesting.  Whatever solution you choose, let us know.  As a side note, I have an additional RPI running two SDRs, which parse various 433MHz and 915MHz sensors.

[mcrossley]

Note that I haven't sorted out the US band yet (it was hindered by the lack of a US transmitter that I do have now, finally) - it means that you need some freq. tweaking to make it 100% work, otherwise it skips about every other packet.

Did you take a look at the US frequencies in my repo - I altered them from the previous values based on what I saw on SDR (though I found the SDR frequency itself to be a bit unstable and temperature dependent - maybe I should have bought a more expensive one!)
The values I came up with are all equally spaced which makes more sense to me than the slightly randomly spaced previous values!

[amino1958]

Nice, sounds interesting.  Whatever solution you choose, let us know.  As a side note, I have an additional RPI running two SDRs, which parse various 433MHz and 915MHz sensors.

Definitely! The RTL-SDR arrives on Monday. The plan is to first run it with the rtldavis software ( at https://github.com/lheijst/rtldavis) and see if I can see some packets and test out the range. If that goes well, work on integrating it with our other sensors. I'm not familiar with GoLang so there's going to be a bit of a learning curve there.

Does the lheijst rtldavis code require Weewx? I not familiar with WeeWx and don't really need it. I just need to see the raw 8-byte packets come though from the ISS. Does WeeWX need to be installed?