Re: [Discuss-gnuradio] multiple antennas and multiple usrps

[Eric Blossom]

On Wed, Jun 25, 2008 at 03:36:02PM -0700, Dan Halperin wrote:
> On Jun 25, 2008, at 3:20 PM, Eric Blossom wrote:
> 
> > On Wed, Jun 25, 2008 at 02:37:48PM -0700, Dan Halperin wrote:
> >> 1) I notice that multi-antenna.py claims to only work with the  
> >> BasicRX
> >> boards. Any reason I can't use the 2 RX paths on each of 2 RFX2400s
> >> assuming the d'board is powered up and configured correctly?
> >
> > The RFX boards don't actually have two receive paths.  They have two
> > antenna ports.  The boards output analog I & Q to the usrp
> > motherboard, and thus two A/D's are required to handle each
> > daughterboard.  With a single USRP and two RFX2400s you can handle two
> > inputs and two outputs.
> 
> So what you're saying is you can't use the TX/RX and the RX2 both for  
> receive at the same time? I guess that jives with the figure here:
> 
> http://gnuradio.org/trac/wiki/UsrpRfxDiagrams
> 
> Instead, that's only to enable concurrent transmit on TX and receive  
> on RX2... that doesn't exactly seem that useful.

Actually, on a system with a LNA on the input and a power amp on the
output, it makes great sense in the typical half-duplex case.

> >> 2) I have a transmitter USRP and a receiver USRP attached to the same
> >> machine. I use usrp.serial_number() as suggested by Eric in many
> >> previous mails to distinguish between them. I have a code loop like
> >> this:
> >
> > Are you loading a different fpga image into the different USRPs?
> 
> Yes, one is (was, I guess?) using std_4rx_0tx.rbf (see 1) and the  
> other was using the default.
> Thanks,
> 
> Dan

That would do it :-)

Please let me know if the (untested) code fragment I sent works out.

Eric