In reply to Kevin: Your path seems pretty similar to mine, I started a few years ago with a RTL dongle and got away with receiving in a few SDR programs available for Mac. After getting bored by that I installed gnu radio and seemingly quickly I got success with getting set-up what I needed. Since everybody can receive but we hams can transmit to I fell in love with the b200mini and bought one. So created some transmitters (like wbfm stereo with RDS) and as long as it was "broadcasting" this worked very well. With a 80W amp I was heard and RDS was decoded remotely.
My next step was to make a simplex nbfm trx so I could use my setup for communicating over a repeater. I never got this to work as I do not seem to be able to get the RX/TX switching to work within Grc. I searched and got answers from this list quickly, Tagged stream. Although I understand the concept, I never got this working and I have the feeling I miss something. I have a hard time formulating the question. The mentioning of the RRC filter is something different and sure I need to get more theoretical background but my math skills are far away from what is needed, currently I combine my extremely demanding job with math learning. As a ham operator, I am interested in a multi mode/band SDR solution which I can expand with digital modes one by one, up to the point where I can transmit analog ATV from say a connected frame grabber and I opted for this as my learning curve. Doing so by looking at examples, related theory etc. If I only could get my b200mini to switch between RX and TX for simplex operations I would be a happy man for now.. (Off topic for this thread). But all examples I found claiming to do so never worked with my setup. (Most seem to switch to null sinks to stop transmitting) General: I completely agree with all of the two cents everyone has send. Although not everybody is getting that deep into it to make use of gnu radio, as said I want my usrp to replace my dedicated rigs. Martijn Verstuurd vanaf mijn iPad > Op 18 mrt. 2016 om 04:10 heeft Kevin McQuiggin <mcqui...@me.com> het volgende > geschreven: > > Hi Martijn: > > Two cents from me, a relative non-technical newbie, also a long-time amateur > radio operator. My educational and professional background is in computing > science and a bit of math. > > I first found gnuradio a few years ago, and had a similar experience to > yours. I played around with it, did some of the tutorials, but quickly got > slain by my lack of technical DSP background, and (back then especially) the > lack of clear documentation on the blocks. > > I got discouraged and removed my gnuradio installation. > > However, I knew that I wanted to know more, and understand gnuradio better, > as the power of the package was obvious to me. I saw this as a learning > challenge. I embarked on what ended up being about 1.5 years of reading and > coding, outside of gnuradio. > > I found a fantastic couple of books, most notably the free "Digital Signal > Processing: A Guide for Scientists and Engineers". See http://dspguide.com. > I eventually bought a hardcopy of the book. > > I used the book to code up some self-learning programs, for example a DTMF > decoder, and got my head around a lot of the DSP concepts. More reading > augmented this, and I returned to gnuradio about a year ago with a $20 RTL > dongle in hand. > > The tutorials now made more sense, and while I was still on a steep learning > hill, things went well. I upgraded my hardware to an Ettus B200, and now > feel a bit on top of things. Stick with the cheap dongle for awhile. I > initially upgraded to the B200 as I wanted to build a transmitter. However > the RX is WAY better on the Ettus unit too, it was a fantastic jump and good > investment. > > If you have time and no particular deadline, I'd recommend this approach. > > As for projects, I've built an FM RDS receiver and decoder, an FM SCA > receiver, an SCA transmitter, Multi-channel HF CW decoder (via an up > converter), and am currently working on a clear channel Inmarsat decoder - > this one is about half done. My approach is to use gnuradio for the > demodulator, then pipe the bitstream to a C program over a gnuradio TCP or > UDP sink. The RDS code, for example, is almost 1000 lines of C, so these > things are not intrinsically "easy". Incredible learning value and sense of > satisfaction though when your code/flowgraph actually works! > > Things like the need for an RRC filter become clear with reading, review of > (say) RDS specs, and head scratching over a couple of weeks. Read about > "matched filters" and you'll understand what the RRC block does. > > My recommendation is to recognize that this is a non-trivial field and big > learning opportunity, and grab a couple of books like the (free) one by Smith > above. Read for awhile, then see where you're at. > > It does grow on you with research, but I also have to say that my knowledge > is "stone knives and bear skins" to quote a popular Vulcan, compared to the > level of knowledge of most of the folks on this list. > > Hope these comments help in some way! > > 73, > > Kevin > (VE7ZD) > > Sent from my iPad > >>> On Mar 16, 2016, at 2:10 PM, Martin Braun <martin.br...@ettus.com> wrote: >>> >>> On 03/16/2016 01:33 PM, Martijn Moeling wrote: >>> I feel there is a gap between the knowledge of the experts and the >>> information for newcomers. My questions have been answered pretty >>> quickly but the answers raise even more questions and confuse me. >> >> This is a common concern, but it's really, really hard for us as a >> community to address comprehensively. There's multiple reasons for that, >> but it all comes down to the fact that writing good tutorials is hard. >> >> Many of us core GNU Radio members have a DSP/Wireless background and >> then moved into GNU Radio. For people like us, you need completely >> different tutorials than for someone who's not familiar with DSP. >> >> Now, there's lots of very good books out there that go into DSP and >> wireless communication. They're usually written to address >> university-level students. But how do we condense them into nice and >> easy tutorials? It's hard. >> It gets exacerbated by the fact that writing tutorials becomes harder >> the more familiar you get with a topic. You lose sight of what's hard, >> and what's not. Unless you're a professional tutorial writer, of course >> -- but we have very few of those. >> >>>> What I need is: >>>> 1) understand the blocks, their purpose and what they do >>>> 2) learn how to create a minimal scenario using grc >>>> 3) learn how to create blocks of my own >>>> 4) create more complicated scenario. >>>> >>>> I wanted to ask the same question in stackoverflow, as I have seen >>>> people from the community hanging around there. But, the amount of >>>> shitstorm coming from there is amazing when asking about learning >>>> pointers... They mark the Q as "opinion-based" immediately. >> >> SO can be tough like that. Also, 'gnuradio' tagged questions don't >> usually get a lot of attention. I'd be happy to see more action on SO, >> but we never really got there. >> >> Back to your list, 3) is comprehensively covered by the guided >> tutorials, as are parts of 2) and 4). 1), however, is where we get into >> the tricky scenario I went into above. >> >> >> I'm afraid I don't have easy answers for you here. All I can say is I >> hope people stay encouraged to submit documentation patches and >> tutorials, to make this all more accessible. We certainly don't want >> this to be available to only an elitist bunch of DSP nerds. >> >> Cheers, >> Martin >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio