Re: [Discuss-gnuradio] USRP1 Clock drift

2011-01-07 Thread Matt Robert
Hi Mike/Nick, Thanks for your help, I tried offsetting the transmitter by a couple of kHz and it all came to life (isn't software radio great like that!) The error of 13kHz was only at 940.2MHz, which is definitely within spec. As Mike explained this correlates to an error of about 6kHz @ 435MHz.

Re: [Discuss-gnuradio] USRP1 Clock drift

2011-01-06 Thread Peter F Bradshaw
Hi Matt; Is it possible to include in your application a monitor which would receive a transmission which you could use as a reference in order to correct your transmitter's local oscillator? It seems to me that this would be a better solution to your problem than modifying the hardware in order t

Re: [Discuss-gnuradio] USRP1 Clock drift

2011-01-06 Thread Nick Foster
On Fri, 2011-01-07 at 10:01 +1100, Matt Robert wrote: > Hi Guys, > > I ran Kalibrate against my pair of USRP1's using GSM900 towers (around > 940MHz) and found my first unit to me 5kHz off and the second was 13kHz off. > > Is this within limits for the built in oscillator? I have been using > the

[Discuss-gnuradio] USRP1 Clock drift

2011-01-06 Thread Matt Robert
Hi Guys, I ran Kalibrate against my pair of USRP1's using GSM900 towers (around 940MHz) and found my first unit to me 5kHz off and the second was 13kHz off. Is this within limits for the built in oscillator? I have been using them to transmit P25 frames around 435Mhz and found that my commercial