Re: [Discuss-gnuradio] New USRP apps

[Marcus D. Leech]

Matt Ettus wrote:
> 
> Quoting "Marcus D. Leech" <address@hidden>:
> 
> > Presumably, you're listening to the FM stations via aliasing in the A/D
> >   sampling, yes?
> 
> Correct.  Since the sample rate is 64 MS/s, A station at 88.5 aliases to 24.5
> MHz.    A station at 103.5 would alias to the same place, so you won't be able
> to separate them if both are transmitting.
> 
> By the way, the ADC can actually sample signals as high as 500 MHz with only a
> few dB of loss, and signals as high as 1300 MHz with about 20 dB of loss.
> 
> Matt

Hmmm--that's interesting.

There's a radio-astronomy band at 408Mhz.  Only a coupla Mhz wide, as I recall.
  Might be interesting to build a filter in front of a couple or three stages of
  ERA-5s and feed it with a 70cm Yagi.  Swing it towards and away from
  Sagitarius and watch the noise floor go up and down...

Are you familiar with coaxial cavity filters?  Very simple to build from
  standard copper pipe and a couple of BNC connectors....

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