Please note: The BLF178P and BLF178XR FM pallet amplifiers were discontinued when NXP introduced the BLF188XR. The BLF188XR is offered at the same cost and it offers better performance. The BLF178P and BLF178XR transistors are still available for sale.
This is a nice, low cost low-pass filter that works great. My signal is VERY clean with this hooked up. No detectable harmonics, spurs, or other interference. I absolutely love the fact that you can hook a meter up to it so your power can be monitored easily on the fly. Accuracy seems good enough (please read below).
I have this mounted in a metal case on standoffs. RF Connections are made with RG316 coax to SO-239 connectors. I have the directional coupler hooked to a 150-watt panel meter that I found on rfparts.com
This was relatively easy for me to setup.