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Re: [Discuss-gnuradio] starting USRP basicRX pickup
From: |
Eric Blossom |
Subject: |
Re: [Discuss-gnuradio] starting USRP basicRX pickup |
Date: |
Fri, 14 Apr 2006 14:16:04 -0700 |
User-agent: |
Mutt/1.5.9i |
On Fri, Apr 14, 2006 at 12:39:45PM -0700, Erik Tollerud wrote:
> I can't seem to find a consistent answer to this - I'm trying to test
> my USRP now that I have the software working correctly, but I can't
> seem to find much anything in the FM or AM bands (usrp_wfm_rcv and/or
> usrp_fft) using the antenna that I bought with the USRP (the "144MHz,
> 430 MHz, 1200 MHz Tri-band 6-inch vertical antenna" one), or just
> various lengths of wire I tried hooking in. It does seem to lock in a
> bit around 100.1 MHz (although I don't think that's a radio station in
> the vicinity), but there's no audio coming out the demod. So should I
> expect to be getting anything without any RF front end? Oh, and I'm
> in Tacoma, WA, so there are a number of fairly strong radio stations
> around...
With no gain or selection in the front end, it's pretty hard to see
anything. However, if you use a 75cm piece of wire as an antenna,
there's a pretty good chance you'll be able to pick up broadcast FM
stations. Note that because we sample at 64 MS/s, when using the
basic rx you can't distinguish 96MHz + N from 96MHz - N.
Try running usrp_fft.py and seeing what you see.
You'll probably have to turn the gain all the way up.
The "right answer" is to use one of the daughterboards that actually
contains a tuner. E.g., TV RX, Flex 400, Flex 2400.
Eric