For most people with the PiAware type feeders, the most convenient place to put this is by the dongle (would need an SMA - MCX pigtail)
If you have a power injector + masthead amp, it goes between the power injector and the dongle ... no need to be concerned about DC up the wire ... it makes no difference
Well done FA making this available, now all we need is:
* a similar sealed container with a PSA4-5043+ based amplifier inside for mast head use (for powering up the line)
* a power injector for use with the amplifier (the amplifier needs 3.3 - 5v @ 33mA - so this could be from USB source)
Then we'd have
FA power injector
I must respectfully disagree on the ordering.
In many circumstances, filtering is needed before
the LNA (amplifier stage), otherwise the LNA will be driven into saturation and will be doing more harm than good. My buddy in So Cal is a good example, with a very large very bristly cell tower a few hundred meters away. At home I have cell towers less than a km away. I run a Mini Circuits SHP-1000 between the antenna feed and the LNA, and clean that up with a SAW. Without the high pass, my LNA (Mini Circuits overkill, ZRL-2300, which has plenty of gain at 1 GHz and high dynamic range) does all sorts of nasty things. Sent my buddy a NHP-1000 and it helps, but I need to send him the gain stage that follows it.
I still think the ideal is a high pass with a very sharp cutoff and low insertion loss -- SHP-1000 or better, as most folks with problems have cell sites in the 800 - 950 range nearby. The cutoff above 1100 doesn't have to be as drastic in terms of dB/octave, as there isn't that much going on until 1800 or so, permitting the use of a less aggressive low pass element, which helps keep insertion loss down. Follow that with the LNA stage (18 - 20dB), a SAW for the narrow band cleanup, and possibly another LNA with around 10dB gain.
The proper filter configuration at the LNA input can provide static/charge protection to the LNA as well. The "protection" in our little SDRs is a pair of diodes. Yes, they provide protection against static buildup, BUT, with a strong enough signal, they conduct (in a manner known in engineering circles as being nonlinear as hell), and become a mixer, throwing all sorts of stuff into the SDR. Another reason to keep from overloading the SDR.
(looking forward to having more than a sporadic few minutes at a time to spend on this stuff again!)