[Discuss-gnuradio] Hardware in Australia for SDR

[Daniel Piccoli]

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


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> Today's Topics:
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>    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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