Re: [Discuss-gnuradio] DBSRX Noise Figure

[David I. Emery]

On Wed, Nov 30, 2005 at 05:12:11PM +1030, Daniel O'Connor wrote:
> On Wed, 30 Nov 2005 16:33, Matt Ettus wrote:
> > A useful application would be to control a calibrated noise source and
> > measure the power in a given bandwidth with it on and off.  This is how
> > a noise figure meter works.
> 
> Noise sources are pretty expensive :(
> We have one at work though, if someone local is interested in testing it :)

        Expensive is somewhat relative.

        I have bought several at the MIT flea for around $75 per,
and one with the cal documents on eBay for around 100.   They take
24-28 volts to turn the noise on BTW...

        And I might note that nothing in tuners used on the USRP is
particularly optimized for noise figure, if one wants good noise figures
one needs external LNAs..

-- 
   Dave Emery N1PRE,  address@hidden  DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."