Re: [Discuss-gnuradio] Hardware in Australia for SDR

[Rob Judd]

Daniel,

It's a homebrew effort. Get in contact with Alan Gray, he has some 4702
tuners for sale to get you started.

Rob


Daniel Piccoli wrote:
> 
> Hi,
> 
> I know the howtos have specified the type of hardware to buy for SDR.
> However, could someone tell me what can be bought in Australia that
> allows the user wide spectrum coverage.
> 
> Also, bandwidth for TV is wider in Australia, does this mean Australians
> need to purchase a different tuner?
> 
> Ta
> 
> On Tue, 2003-09-16 at 00:03, address@hidden wrote:
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> > Today's Topics:
> >
> >    1. Success (kinda) (Alan Gray)
> >    2. Re: Success (kinda) (Rob Judd)
> >    3. Re: Success (kinda) (Eric Blossom)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Mon, 15 Sep 2003 13:05:00 +1000
> > From: Alan Gray <address@hidden>
> > Subject: [Discuss-gnuradio] Success (kinda)
> > To: address@hidden
> > Message-ID: <address@hidden>
> > Content-Type: text/plain; charset=us-ascii
> >
> > All,
> >
> > I've been working on putting together a circuit to use the
> > microtune 4702 tuners I have and I think I've almost got it
> > nailed. At the moment I'm sampling the 36MHz IF at
> > 20MSample/sec which aliases the centre to 4MHz (reversed). I'm
> > just trying to demodulate and listen to FM signals currently,
> > however they're not sounding incredibly great.
> >
> > I had a quick search through the archives here and found a
> > thread on "Why FM doesn't sound good" so before I go nuts
> > trying to figure out just why I'm not getting a good sounding
> > audio stream I thought I'd ask just now "not good" FM sounds
> > using the other hardware.
> >
> > Basically what I'm hearing sounds like a radio which is tuned
> > to about 50KHz away from the actual carried frequency. I can
> > make out beats and baselines but it sounds as if I'm missing
> > the high end frequencies. I can make out when words occur, but
> > again they're very distorted and it's hard to determine what
> > is being said.
> >
> > Is this consistent with the results obtained by others or do
> > you get a clearer output? If others do get a clearer signal,
> > can anyone suggest a possible fix?
> >
> > Thanks
> > Alan
> >
> > Is th
> >
> >
> >
> >
> > ------------------------------
> >
> > Message: 2
> > Date: Mon, 15 Sep 2003 13:39:36 +1000
> > From: Rob Judd <address@hidden>
> > Subject: Re: [Discuss-gnuradio] Success (kinda)
> > To: "address@hidden" <address@hidden>
> > Message-ID: <address@hidden>
> > Content-Type: text/plain; charset=iso-8859-2
> >
> > Alan,
> >
> > Good to see you're making progress. How certain are you of the exact IF
> > frequency of the 4702 tuner? I know the datasheet says 36MHz but then
> > the 4706 is at 36.125MHz so it cvould be slightly out. The other
> > possibility is that you are being bandwidth limited by your soundcard,
> > which is equally likely.
> >
> > I haven't started fiddling with the tuners you sent me yet, because I
> > got distracted into designing a 5W linear for the SDR-1000.
> >
> > BTW, I have a Wavetek 3000-200 RF Signal Generator for sale at $695.00
> > plus shipping if you know anyone interested. You probably have the Uni's
> > facilities at your disposal, but maybe someone you know is looking for
> > one. It's listed on the VK-HAM website.
> >
> > Good luck!
> >
> > Rob
> >
> >
> > Alan Gray wrote:
> > >
> > > All,
> > >
> > > I've been working on putting together a circuit to use the
> > > microtune 4702 tuners I have and I think I've almost got it
> > > nailed. At the moment I'm sampling the 36MHz IF at
> > > 20MSample/sec which aliases the centre to 4MHz (reversed). I'm
> > > just trying to demodulate and listen to FM signals currently,
> > > however they're not sounding incredibly great.
> > >
> > > I had a quick search through the archives here and found a
> > > thread on "Why FM doesn't sound good" so before I go nuts
> > > trying to figure out just why I'm not getting a good sounding
> > > audio stream I thought I'd ask just now "not good" FM sounds
> > > using the other hardware.
> > >
> > > Basically what I'm hearing sounds like a radio which is tuned
> > > to about 50KHz away from the actual carried frequency. I can
> > > make out beats and baselines but it sounds as if I'm missing
> > > the high end frequencies. I can make out when words occur, but
> > > again they're very distorted and it's hard to determine what
> > > is being said.
> > >
> > > Is this consistent with the results obtained by others or do
> > > you get a clearer output? If others do get a clearer signal,
> > > can anyone suggest a possible fix?
> > >
> > > Thanks
> > > Alan
> > >
> > > Is th
> > >
> > > _______________________________________________
> > > Discuss-gnuradio mailing list
> > > address@hidden
> > > http://mail.gnu.org/mailman/listinfo/discuss-gnuradio
> >
> >
> >
> > ------------------------------
> >
> > Message: 3
> > Date: Sun, 14 Sep 2003 23:33:39 -0700
> > From: Eric Blossom <address@hidden>
> > Subject: Re: [Discuss-gnuradio] Success (kinda)
> > To: Alan Gray <address@hidden>
> > Cc: address@hidden
> > Message-ID: <address@hidden>
> > Content-Type: text/plain; charset=us-ascii
> >
> > On Mon, Sep 15, 2003 at 01:05:00PM +1000, Alan Gray wrote:
> > > All,
> > >
> > > I've been working on putting together a circuit to use the
> > > microtune 4702 tuners I have and I think I've almost got it
> > > nailed. At the moment I'm sampling the 36MHz IF at
> > > 20MSample/sec which aliases the centre to 4MHz (reversed). I'm
> > > just trying to demodulate and listen to FM signals currently,
> > > however they're not sounding incredibly great.
> > >
> > > I had a quick search through the archives here and found a
> > > thread on "Why FM doesn't sound good" so before I go nuts
> > > trying to figure out just why I'm not getting a good sounding
> > > audio stream I thought I'd ask just now "not good" FM sounds
> > > using the other hardware.
> >
> > I'm assuming that you're tuned to a broadcast FM station, right?
> >
> > If you run adc3_fft and look at the spectrum, is there a nice juicy
> > spike where you expect your IF to be?
> >
> > Have you experimented with the RF and IF gain settings for the tuner
> > module?  For lowest noise figure, you want to max out the RF gain
> > before ramping up the the IF gain.
> >
> > In fm_demod1 and/or hifi_fm did you you change the definition of the
> > IF frequency?
> >
> > > Basically what I'm hearing sounds like a radio which is tuned
> > > to about 50KHz away from the actual carried frequency. I can
> > > make out beats and baselines but it sounds as if I'm missing
> > > the high end frequencies. I can make out when words occur, but
> > > again they're very distorted and it's hard to determine what
> > > is being said.
> >
> > Of the two wide band FM receivers we've got, hifi_fm sounds better
> > than fm_demod1.  In any event fm_demod1 doesn't suck completely (sort
> > of like a low cost hand held radio from the old days).  It's not
> > really processing a wide enough piece of the spectrum to grab it all
> > (related to the fact that there aren't nice integer decimation factors
> > that get us from the IF input sampling rate to the sound card output
> > rate).  hifi_fm interpolates, and does a couple of other things more
> > right, and as a result sounds quite good.
> >
> > If anyone's looking for a not too hairy project, building a version of
> > hifi_fm.cc that decodes the L-R stereo info wouldn't be too hard.
> >
> > > Is this consistent with the results obtained by others or do
> > > you get a clearer output? If others do get a clearer signal,
> > > can anyone suggest a possible fix?
> > >
> > > Thanks
> > > Alan
> >
> > If you like I can send you some audio samples of FM I've
> > demodulated...
> >
> > Eric
> >
> >
> >
> > ------------------------------
> >
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> >
> > End of Discuss-gnuradio Digest, Vol 10, Issue 8
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