Dean Sauer wrote:
On Mon, 15 Sep 2014 20:07:24 -0400, Ed Beroset wrote:
http://www.rtl-sdr.com/rtlamr-rtl-sdr-receiver-900mhz-ism-smart-meters/
The Sensus devices are on 900Mhz licensed PCS frequencies. 1W meters, and
30W bases... the local mafitilty has recently stuck some up on a their
poles as they obviously had some coverage issues.
But outside of that they are not going to release, to the general public
at least, any data.
All the FCC OET exhibits with this are "Permanent Confidential."
See:
http://fccid.net/number.php?fcc=SDBIDTB002&id=640613
http://fccid.net/document.php?id=1338971
That's not correct. They don't make schematics available to the public
(probably because they fear revealing them to competitors) but the test
report is certainly available and tells you most of what you would want
to know about the frequency bands, channel spacing and modulation:
https://apps.fcc.gov/eas/GetApplicationAttachment.html?id=1338973
Based on the heavily PR puff and sanitized info on their site this uses
an IP network, with most likely an IPv6 (blech!) addressing system for
meters etc... and controlled via DNP3 protocol. Which with the IP nature
maybe encrypted via VPN (IEEE1179).. They don't mention anything about
the security other than their monitoring of tampering, moving a meter
etc..
Typing the name of the company and the words "meter" and "security" into
a search engine yields rather a lot of information, so I'm not sure why
you were unable to locate it.
Based on one of those RF is killing me whackos [1], did turn up some info
that the meters may be transmitting on 940.1125MHz, and monitoring this
I do get digital bursts on this channel.
The FCC report states that it operates in any of 9 different bands at 2
different power settings and 5 distinct modulation modes. It also gives
numbers & specs for all of those.
And based on the emissions
designator for the grant its some sort of 4-9Khz wide FM signal with
possible a subcarrier on some models and possibly TD as well.
Base station specs (again, easily found with a search engine) for their
equipment pretty clearly state that the TX side uses 2-FSK at 5-10 kbps
and RX is 7-FSK at 4-8 kbps.
I will try to capture some audio to post some place if I can...
Alternatively, there are many available gnuradio blocks from others that
can be used as-is or modified for your own particular purposes.
I don't use that software, nor am I going to. May be the bees knees and
all that.. just doesn't connect with me. Bloated, PITA to install, setup,
use, and huge amounts of issues in re stuff that doesn't work with newer
versions and vice versa...
It's actually pretty easy to install in my experience. Just run this
script: http://www.sbrac.org/files/build-gnuradio
Naturally, if anything goes wrong, you'll need to know what you're doing
with Linux to troubleshoot, but I haven't really had any significant
difficulty with it. Not sure how you could claim it's "bloated" unless
you could point me to something significantly smaller that does what it
does. If you know of such software, please name it and provide a
pointer to its source code. I'm sure there are many here who would be
interested.
again, once you have a block, or a whole subsystem, you can easily
compile it into a CLI-based Python program, that that opens up a whole
other world of exploration for those of us who prefer CLI.
Thats great, but some one else will need to provide that "compiled"
program. I am a willing tester.
If, by that, you mean you don't yet have the skill or knowledge required
to be able to design the radio based on working blocks, then you might
consider using gnuradio to learn something new. I don't yet consider
myself an expert with gnuradio, but find that's it's quite useful as a
platform for trying out digital radio techniques and find it quite fun
and interesting to explore that way. You might, too, if you can get
beyond your many apparent prejudices.
Ed
