Re: [Discuss-gnuradio] Success (kinda)

[Rob Judd]

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
> 
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