[lug] decoding weather data via radio Was: Time sync w/GPS or radio

[Mike Stanczyk]

On Mon, 12 May 2008, Nate Duehr wrote:

> You'll have to either find someone who has completely reverse-engineered the 
> product, or ask Oregon Scientific if they'll share the modulation type and 
> the protocol with you.  (Doubt it.)
>
> Which bit in the bitstream represents what if it's binary?
>
> Some "hints" might be who makes whatever RF chipset Oregon uses... many 
> manufacturers making low-end/low-priced products are going to often pick a 
> standard off-the-shelf RF module and then put their own data packets or 
> stream of information over those... so you can get the modulation type, 
> speed, etc... from the datasheets for the chipset, but you still won't know 
> which bits are temperature, humidity, wind speed... nor how they encoded 
> them... that will require bench time, and a lot of experimentation to 
> reverse-engineer it.
>
> Unless... the magic of Google shows you where someone else has already done 
> all of that work and published it.  Or if Oregon is an open company about 
> such proprietary things as their little weather stations.  Most companies 
> making products that are priced anywhere from 3x to 10x the worth of the 
> components (most Oregon Scientific circuit boards are pretty simple) aren't 
> going to make information easily available about how to intercept their 
> protocol... they'd rather sell you another receiver, and another for the 
> other room, and another for the garage... you get the idea.
>
> --
> Nate Duehr, (Since you asked for hams... WY0X)
> nate at natetech.com

You're spot on in all of this.  So with my weak Google-Fu I've got this:
A decode of the old digital format
http://www.tinaja.com/glib/muse151.pdf

And a claimed compatable DIY weather station:
http://www.techdesign.be/projects/012/012.htm

So my first step is go look at what's being broadcast and compare.
Is there software in the ham community that can frequency analyize via
the sound card?  I've got the scanner of course... ;-)

Mike