Re: [Discuss-gnuradio] lowest power of the signal that LFRX can receive

[Alexandru Csete]

On Wed, Mar 16, 2011 at 1:07 AM, Marcus D. Leech <address@hidden> wrote:
>> Dear all,
>>
>> What is the lowest power of the signal that LFRX can receive?
>>
>> Really appreciate any of your help
>>
>> Yan
>>
> The LFRX has almost no gain, so you're limited by the noise floor of the
> ADC.  In the USRP2, you can probably reliably detect
>  signals down to about -60dBm or so.  In the USRP1, you need somewhat more
> signal, about -50dBm or so.  But those are
>  ballpark numbers.  But it depends on the details, and what kind of signals
> you're trying to detect, and whether you want to
>  demodulate them, or merely detect their presence, etc.

Using a signal generator I could measure the "CW sensitivity" down to
about -90 dBm. Using a 2 kHz filter this produced a tone clear enough
for me to decode morse code. With a tuned vertical antenna ~10 meters
long, I get very good reception of AM broadcasting and ham radio
traffic around 7 MHz. I was using USRP1.

Alex