Replacing Fans in USRP N200s

Two fairly old USRP N200s radios (about 4 years old) had issues with their fans. One was completely dead and the other was operating, but noisy. I was not able to get replacement fans from the manufacturer, but it turned out that form factor is completely standard, so I ordered fans with the same size and similar specs from Digikey. They installed just fine in the radios. Here is a picture of the old fan (top) and the replacement. The part numbers are easily readable.

A Second-Generation Front-End Unit

Itamar Melamed and I designed a second generation front-end unit. It contains a SAW filter, an RF limiter to protect the filter and the radio, and a bias tee with a DC limiter, allowing the unit to be used with both active antennas and antennas that present a DC short. It is small and fits within a USRP N200.

The full details are available at http://dx.doi.org/10.1016/j.icte.2017.01.002.