Received signal drifts from console reading

[ar0berts]

Hi, I am puzzled by the behaviour of rtldavis packets. over a 24 hour period they drift away from the packets received by the console. The set up is ubuntu 20.04 LTS with a debian type installation of weewx 4.6.1 and a standard Realtek dongle with an aerial next to the Davis console. The ISS is a Vantage Vue 6250.

lsusb: Bus 003 Device 073: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

I attach a screenshot of the weewx html report 10 minutes after a reset showing changes in humidity, temperature wind direction. The barometer and inTemp come in separately from a BMP280. There are no other Also a picture of the console just before the reset and syslog before and after the reset. There are no houses (or weather stations anywhere near me ~1km so I can't think that I'm picking up another weather station.

I hope there is a simple explanation - help and advice humbly received! Andrew March-01-2022.txt rtldavis_weewx-conf.txt

[lheijst]

Hi Andrew,

Looking at the syslog my first thoughs are the program is receiving packets from more than one ISS station. To be sure I need more syslog data: a few hours before a reset followed by a few hours after the reset would be fine to be sure.

Best regards, Luc Heijst

Verstuurd vanaf mijn iPad

Op 1 mrt. 2022 om 04:10 heeft Andrew Roberts @.***> het volgende geschreven:

 Hi, I am puzzled by the behaviour of rtldavis packets. over a 24 hour period they drift away from the packets received by the console. The set up is ubuntu 20.04 LTS with a debian type installation of weewx 4.6.1 and a standard Realtek dongle with an aerial next to the Davis console. The ISS is a Vantage Vue 6250.

lsusb: Bus 003 Device 073: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

I attach a screenshot of the weewx html report 10 minutes after a reset showing changes in humidity, temperature wind direction. The barometer and inTemp come in separately from a BMP280. There are no other Also a picture of the console just before the reset and syslog before and after the reset. There are no houses (or weather stations anywhere near me ~1km so I can't think that I'm picking up another weather station.

I hope there is a simple explanation - help and advice humbly received! Andrew

March-01-2022.txt rtldavis_weewx-conf.txt

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[ar0berts]

Will do Luc. Give me a couple of days and I will get back to you.

Many thanks,

Andrew

On 1 March 2022 09:59:24 GMT, Luc Heijst @.***> wrote:

Hi Andrew,

Looking at the syslog my first thoughs are the program is receiving packets from more than one ISS station. To be sure I need more syslog data: a few hours before a reset followed by a few hours after the reset would be fine to be sure.

Best regards,

Luc Heijst

Verstuurd vanaf mijn iPad

Op 1 mrt. 2022 om 04:10 heeft Andrew Roberts @.***> het volgende geschreven:



Hi,

I am puzzled by the behaviour of rtldavis packets. over a 24 hour period they drift away from the packets received by the console. The set up is ubuntu 20.04 LTS with a debian type installation of weewx 4.6.1 and a standard Realtek dongle with an aerial next to the Davis console. The ISS is a Vantage Vue 6250.

lsusb: Bus 003 Device 073: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

I attach a screenshot of the weewx html report 10 minutes after a reset showing changes in humidity, temperature wind direction. The barometer and inTemp come in separately from a BMP280.

There are no other

Also a picture of the console just before the reset and syslog before and after the reset. There are no houses (or weather stations anywhere near me ~1km so I can't think that I'm picking up another weather station.

I hope there is a simple explanation - help and advice humbly received!

Andrew

March-01-2022.txt

rtldavis_weewx-conf.txt

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[ar0berts]

Luc, I am 99% certain you are right about another Davis Vantage ISS in my locality.

I have three sets of data:

First a syslog where the console and the rtldavis stanza in weewx.conf are set at ID=1 . I manually changed the ISS ID part way into the logging at 15.09 hrs to ID=7. This caused the console to show no ISS data but the cheap RTL dongle carries on looking at channel 1. syslog_channelHop_4-3-2022.txt

The second data set is a syslog with the console, rtldavis and the ISS set to an ID=1 with a hard restart of weewx part way through syslog_5-3-2022_Restart_Weewx.txt

Finally a syslog with the console, rtldavis and the ISS set to an ID=7. The console agrees with the pkts :-) Syslog_All_Set_to_ID-7.txt

I will track the station and weewx over the next few days and then close the issue. The learning point is that the RTL dongles are very sensitive and can track a station a long way away.

A final mystery in the data is 'hail' and 'hailRate' packets - the ISS manual doesn't mention such a sensor.

Thanks for sorting this out.

Andrew