I have a (blue) FA Pro Plus, FA 1090Mhz antenna, LMR400 cable, running off a Raspberry Pi 0W. It runs well enough, but debating on adding a filter too? Thinking it’s just $15 and since I’ve already invested this much, might as well. Would it be an improvement?
I run cavity filters on all my devices. Even if they are the Pro plus(blue) or a Hab/Nevis Amp/filter.
I am in NYC with lots of noise. They really help.
The FA filter is worth a try. Maybe redo the gain setting afterwards.
Yeah, at just $15, I guess I have nothing to lose. I’ll add one and see if there is an improvement. 
Same here, in Fort Lauderdale, as Mr Hawkes.
The inescapable high noise environment at this local requires the addition of the F/A filter even for the Pro Plus.
I ordered one and it’ll be here in a couple of days, so will see how much of an improvement there is. I expect some as this is a noisy environment as well. My main issue remains getting the 1090Mhz antenna mounted above th roofline. I’m in an apartment on the top third floor. I just have the FA 1090Mhz antenna mounted right on the grill/radiator of a air conditioner unit on the balcony and then running LMR400 to a RPi0W inside. Not ideal (especially when AC is on), if you look at my reception you’ll see it’s pretty good to the East, but lacking in other directions. That’s because the antenna is up against the wall. I’d like to get it above the roofline, which is possible. I have a magmount Omni-directional antenna that is bonded to the top of the ACU that extends over the roof. I use that one for SDR. I’m thinking of various ideas for a mast for the 1090Mhz antenna. Perhaps PVC, clamped onto the ACU and then a standoff from the PVC to the 1090. That’s all I have really to work with. It would be too much of an eyesore on the railing, and besides I already have a VHF/UHF DBJ-1 on the railing, a length of PVC to clear the roof for the 1090 seems best bet. Once I get tgecabtenna better figured out, I’d also like to move the RPi0W outside. Waterproof everything and run it off solar with battery backup. That’s the end goal, anyway.
If you look at the design of the FA antenna, the dipole is located in the fiberglass above the metal bit at the bottom. You shouldn’t need a standoff if the fiberglass part is in free air. I don’t know how you have it mounted to your ACU, but if the fiberglass part is located next to metal it will increase the capacitance of the antenna, tuning it for lower frequencies. I used to have mine next a vertical aluminum balcony railing, and moving it just a few inches further away made a dramatic difference in messages received.
The metal mounting bracket is very reflective and visible from the street, so I don’t use it. The antenna itself is practically invisible. The Pi can get very warm if in a sealed container in the sun. I would find a location for it that doesn’t get any direct sunlight.