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
<address@hidden> 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
>
>
>
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