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Complete Newb Question

Posted: Thu Oct 05, 2017 6:44 am
by sdrnewb
Hi, I searched the boards and didn't see an answer to this and have been trying to find an answer on Google. Maybe my inexperience is keeping me from the right search terms.

I don't really understand how you use SDRuno to demodulate a data signal. Specifically, I want to grab the 900Mhz signal from my itron power meter. I've seen code for interfacing directly with an RTL-SDR (rtlamr), but just from a core concept perspective I think I'm missing something. Do I need to write my own program to interface with the SDRPlay directly, or interface with SDRuno as middleware through an API, or does SDRuno have some capacity to demodulate a signal within the application? I'm not afraid of writing code (or cribbing off of rtlamr), but would like to better understand how SDRuno supports the demodulation of signals. I'm very new to SDRs, and maybe should have started with a simpler device (RTL-SDR?) but I hate buying things twice and just figure the SDRPlay is a good place to start.

Can anyone offer help?

Re: Complete Newb Question

Posted: Thu Oct 05, 2017 7:43 am
by sdrnewb
I may have answered my own question, but would appreciate anybody telling me if I'm on the right track.

It looks like one would use a program like MultiPSK to do the demodulation of signals captured by SDRuno along with a virtual audio cable. The protocol used by the Itron meters is called Encoder Receiver Transmitter (ERT) and is defined here: https://en.wikipedia.org/wiki/Encoder_receiver_transmitter.

It doesn't look like MultiPSK has ERT as a built in mode, but am assuming I have some flexibility to define a custom mode.

Does that sound about right? Are there alternatives to MultiPSK you would recommend for my situation?

Re: Complete Newb Question

Posted: Thu Oct 05, 2017 12:26 pm
by mikexeno
SDRuno will not decode a digital signal internally. SDRuno will allow you to pipe that "digital signal" into a decoder that will be able to handle it. If MultiPSK can decode ERT it would just be a matter of setting your VAC send and return cables in both programs.

Re: Complete Newb Question

Posted: Thu Oct 05, 2017 12:27 pm
by bob550
I also use MultiPSK for data decoding from my SDR, along with virtual audio cable. ERT does not seem to be supported, however, at least in the free version. The focus seems to be more on the more common Amateur and professional digital modes.

Re: Complete Newb Question

Posted: Fri Oct 06, 2017 6:11 am
by sdrnewb
Thanks everyone, that helps clear things up for me. It sounds like MultiPSK doesn't let you define custom modes, eh? I'll be getting my equipment next week and can't wait to start experimenting with it. Reading further on Wikipedia about ERT and David Knaack's awesome blog post about it, it can't come soon enough.

Re: Complete Newb Question

Posted: Fri Oct 06, 2017 6:13 am
by sdrnewb
Oh, and here's the link to David Knaack's blog post I mentioned earlier.
http://davestech.blogspot.com/2008/02/itron-remote-read-electric-meter.html