On Fri, Sep 10, 2010 at 03:59:34PM -0400, Scott Storck wrote: > Jason and Marcus, thanks for your responses. I was afraid that this was the > case. > > Is there a daughterboard out there (besides the BasicRX) that can support 4 > antennas on a single USRP?
Just LFRX > > The other option that would work for me is connecting antenna 0 to WBX 0 and > connecting antennas 1-3 to WBX 1 through a commutator to switch them at a > sub-1 kHz frequency. Can you tell me if any of the unpopulated headers on > the WBX board are digital outputs that could potentially be used to generate > a switching signal and/or low rate ADC inputs that could be used to sample a > switching signal generated elsewhere? You could already switch between the 4 antenna ports (2 on each WBX) using the antenna switches built into the WBX at sub-kHz speeds. If you really needed to solve the antenna switching problem externally, there are GPIOs available on the some of the 0.1" pin headers, check the schematics here: http://code.ettus.com/redmine/ettus/projects/public/documents > > Finally, what it would take for 2 USRPs to operate a total of 4 WBXs > coherently? I assume this would at least require connecting Clock Out on > USRP0 to Clock In on USRP1, but is that enough to get all 4 WBX PLLs locked > together? Also, does using two USRPs simply mean that the max USB data rate > for each USRP is halved, or is the effect more severe? If you want 4 coherent RX using WBX, what you want is 4 USRP2's, 4 WBX's and a GPSDO to supply 10MHz Refclock and PPS signals to all the USRP2's. You would also need 4 separate Gigabit ethernet ports on your host PC. Then, you will have 25Msps from each receiver. > > Thanks, > Scott > <ssto...@gmail.com> > > On Fri, Sep 10, 2010 at 3:19 PM, Jason Abele <ja...@ettus.com> wrote: > > > On Fri, Sep 10, 2010 at 12:04 PM, Scott Storck <ssto...@gmail.com> wrote: > > > I have a USRP and two WBX daughterboards. Is it possible to use 4 > > > independent RX antennas (all tuned to the same frequency) with this > > hardware > > > setup? > > > > Scott, > > > > The WBX has only one (I/Q) receiver per daughterboard. The two > > Antenna ports (TX/RX and RX2) are for convenience to enable a single > > Antenna on the TX/RX in half duplex or a dedicated RX antenna on RX2. > > The WBX merely switches the input of a single RX chain between those > > two antenna ports based on user settings. > > > > So, only 2 receivers are possible with your USRP + 2 WBX setup > > > > Jason > > > > On Fri, Sep 10, 2010 at 3:22 PM, Marcus D. Leech <mle...@ripnet.com> wrote: > > I have a USRP and two WBX daughterboards. Is it possible to use 4 > independent RX antennas (all tuned to the same frequency) with this hardware > setup? > Specifically, here's what I'm trying to achieve: > Antenna 0 -> Side A WBX, RX/TX port -> ADC0 -> DDC0I > Antenna 1 -> Side A WBX, RX2 port -> ADC1 -> DDC1I > Antenna 2 -> Side B WBX, RX/TX port -> ADC2 -> DDC2I > Antenna 3 -> Side B WBX, RX2 port -> ADC3 -> DDC3I > > I am trying to modify gnuradio-examples/python/multi-antenna/multi_fft.py to > make this happen. I've got it running, but I can't seem to get the WBXs to > use the antennas connected to their RX2 ports. > > Thanks, > Scott > <ssto...@gmail.com> > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > No, you will not be able to make that work. There are *not* two > independant Rx paths within > the WBX, only two different antenna ports, which you can switch the Rx > chain between, but there > is only 1 Rx chain. > > -- > Marcus Leech > Principal Investigator > Shirleys Bay Radio Astronomy Consortium > http://www.sbrac.org _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
