>>> However, the WBX has enough internal leakage between tx and rx that we >>> gave up on single-daughterboard full duplex. >>> >> >> Just a heads up, you had not tried WBX without C1 installed on the >> grand-daughterboard, or even without the grand-daughterboard at all, >> just using J202 and J201 on the main WBX board, you might see if one >> of those scenarios could meet your tx-rx isolation requirements. >>
Sorry, missing and *if* in there ( ... Just a heads up, if you have not ... ) Basically, C1 allows for reception on the TX/RX antenna port, it connects the two T/R switches. However, if you are looking to do full-duplex, you will not be receiving on the TX/RX port anyhow, just RX2. So rather than having an implicit leakage path through the T/R switches (RF switches rarely give more than 20-30dB isolation, depending on frequency), you can remove C1 on the grand-daughterboard and improve isolation at the expense of not being able to receive on the TX/RX port. If you want to go even further, you can remove the grand-daughterboard entirely and install SMA connectors in J201 and J202. You will also need to move a capacitor to AC couple J201 and J202 to the circuit. Jason _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
