Frequency and modulation used by WH1080

[kjartani]

Hello to you all.
Im new in here but I am sure to get ansers to my questions.
Im building a "slave" receiver to my weather station WH1080.
All I know about the transmission is that the 868mhz band is beeing used.
What I need to know is the accect frequency used by the WH1080 and what type of modulation that is used.
I am going to use this "slave" receiver to be able to extract the raw data from the sensors, transfer the data to a my "webserver in a box" which will upload the data to my remote server for storage and web presentation.
The project will be presented and shared with everyone that might be interested.

Regards

Kjartan Iversen

[AllyCat]

Hi,

If you succeed, that will be a considerable addition to the knowledgebase! Very little seems to be known about the RF protocol of these FO stations.

For low cost, I guess that they use a standard Surface Acoustic Wave filter with a nominal frequency in the range 868.0 to 868.6MHz. For once Wikipedia has let me down (quoting the USA 915MHZ frequency), so the best reference I have found so far is this. I suspect that FO transmit less than 25mW, but I think the duty cycle is more than 0.1% (but not by much, the transmit pulse seems to be about 50ms every 48 seconds, however there are extra bursts for the RTC, etc.).

I think that we have all assumed that the WH108x uses FM transmission, but my recent measurements on the transmitter current of the "solar" WH3080 suggests that it uses AM (with a much longer transmit cycle of several hundred milliseconds).

Cheers, Alan.

[kjartani]

Hi.
I think that 868.3Mhz is the frequency used and that the modulation is ASK but the receiver module I wanna use are fixed frequency so I better be sure.
I have sent a request to the producer of WH1080 about this but havent heard anything yet.
I will be back with more about this topic and my project.
In the meantime I rely on you good people.

Regards
Kjartan

[ejay]

I think that 868.3Mhz is the frequency used and that the modulation is ASK but the receiver module I wanna use are fixed frequency so I better be sure.
I have sent a request to the producer of WH1080 about this but havent heard anything yet.

It is very unlikely they'll give you the details of the modulation. They'll more likely say you'll need to buy a replacement base station (if they reply at all). After all, they want to maximise their profits, and giving away technical information is like a software programmer (for proprietary software) giving away details of the source code.

[kjartani]

I have been doing some research and have found that the frequecies used by weatherstations are 433.92MHz or 866.3MHz.

The modulation used are ASK.

I have ordered parts to build the slave receiver and will be back with further info of my project.

Kjartan

[mcrossley]

Are you aware of this?

I have an 868Mhz RFM01 module hooked up to my Pi, but haven't had time to get the Pi working on my network out in the shed yet (near the transmitter). The RFM01 modules are cheap (~£3) and the frequency is programmable - within the band range you purchase.