14 Aug
2012
14 Aug
'12
5:39 a.m.
so it is *designed* for FM? That's encouraging because mostly that is all
I really need from it, only all my experiments so far have yielded only
AM-quality sound, but it's good to hear because it means there's *hope* and
so I'll just keep hanging in there until an FM recipe surfaces :)
On Mon, Aug 13, 2012 at 7:58 PM, Adam Nielsen <a.nielsen(a)shikadi.net> wrote:
This clumsy Analog to Digital Converter / USB
--
*Have Blog, Will Travel: blog.teledyn.com*
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interface Chip, does not have the Audio dynamic
range needed for my
purposes.
That's because it's only designed for FM radio. Anything more would have
been overkill for the manufacturer's purposes. This is still excellent
value for $20 and hasn't been much of a stumbling block for what most
people have been doing so far.
The infuriating predilection it has to crash every time you want
to shift frequency is another disadvantage.
I'm not sure where you're looking in the docs, but if you're using
Balint's USRP ExtIO (as oppposed to the - I think - Osmocom ExtIO) then
there are two sets of code for the tuner. The default one offers slightly
wider frequency range, but crashes as you have seen. If you add
"tuner=e4k" to the device hint then it will switch to the newer code, which
doesn't crash, at the expense of having some gaps in the frequency coverage.
First, I attached a high gain audio amplifier's input directly to the
Tuner's output then to a 96K Sample per
Second, 24 Bit Audio card to
observe
a high quality spectral image from the tuner.
Presumably this reduces your bandwidth from 3.2MHz to 96kHz, which is
24kHz too low to properly receive wideband/consumer FM radio. Since many
people are using the RTLSDR has a kind of glorified RF scanner, I am
wondering whether you're trying to do something you really should be doing
on a high end device like the USRP?
Next is to hack into and record the I2C sent to the Tuner, so it may be
controlled independent of that infuriating
RTL2832. If anyone has done
this,
please share your code and understanding.
Don't quote me on this but AFAIK the RTL just passes the I2C commands
through unchanged. This is how the existing E4000 tuner code was able to
be adapted to the RTL2832 so quickly.
This list probably isn't the best place to ask about this sort of thing -
it's mostly developers focused on improving the hardware rather than
getting people started with it. I strongly recommend switching to the
ultra-cheap-sdr list[1] instead, which has many more people able to help
beginners. Your question about the device crashing is answered quite
often, for example. These people can also point you to the many 'getting
started' guides, which do explain clearly with screenshots where to put
device hints and the like.
Cheers,
Adam.
[1]
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