How to bypass the ISM band filter on the RFX900?


My current application needs to work on ISM band, and there is an ISM
filter on RFX900, how to remove or bypass the ISM band filter on the



“The filter affects both TX and RX, but not the auxiliary RX path
(RX2). If you just want to receive, use the 2nd SMA port and make sure
to set that in the software. If you want to bypass the filter for
transmit, you will need to put a cap of about 50 to 200 pF in the
path, and cut the traces to the filter.”

">> You have to de-solder it. Optionally (in case you don’t want to

the part, since it will be difficult to reinstall it), you could
install a jumper (zero-ohm resistor) or (better) a small 10pF
capacitor in parallel (there is a pad), but this may cause some weird
side-effects if you use the USRP in the ISM band after installation.

You need to put a cap of between 25 and 500 pF in that location, AND you
need to cut the traces which go to the filter. If you don’t you will
get weird resonances.