FlightAware Discussions

FA ProStick Plus with FM filter

I’m setting up a PiAware to site at my brother’s house in NH and trying to figure the optimal configuration. He does have nearby FM broadcast towers very close by and I do have an RTL-SDR FM bandstop filter he can use. If I set him up with the ProStick Plus is that good with the FM filter attached, or would it be better to use the orange ProStick and separate FM bandstop and 1090 bandpass filters and then in which order? I’ve ruled out the rtl-sdr dongle because it lacks the LNA and adding that increases the complexity more than I want at his place.

For 1090 MHz the yellow prostick is never better than the blue prostick.

If there is also something non-FM near the house a FA filter might be better to avoid overloading the LNA.

Without trying it it’s hard to tell.

Gotta say though, the rtl-sdr isn’t much more than a filter in complexity.
Turning on the bias-t could be tested on your system if you already have one running.
But i understand it’s added complexity in the software.

From reading I was thinking the blue one is the same as the orange one but has the 1090 filter built in, and that both have the same LNA. However, is the 1090 MHz filter in the blue ProStick Plus sufficient to block FM signals, and the same question applies to the orange ProStick with FA external 1090/978 filter. Or is the FM filter still required (i.e. are the ADS-B filters alone not good enough to block those to avoid overloading the tuner)?

I’ve been playing with the silver RTL-SDR and realize for ADS-B that it absolutely requires an LNA. I recently got the RTL-SDR wideband LNA and configured rtl_biast and added the 1090/978 filter (which decidedly has to go on the antenna side of the LNA). I think that combination outperforms the orange plus FA filter but I haven’t done a comparison of that to the blue ProStick Plus yet.

I just found an excellent discussion on this at:


Based on this I think I should use the ProStick + external filter for his site due to the very close FM towers (1/4 mile) in order to initially block out those signals before they get to the LNA. That site didn’t say anything about needing a separate FM bandstop so I’ll set it up initially without it.

Why the wideband? The filtered one is so much better for 1090 MHz.
Using extra external filters won’t get you near the performance.

Anyway the blue stick has a SAW filter after the LNA.

The extra FA filter you can buy has a much wider pass band and doesn’t attenuate as well as the SAW filter.
SAW filters have a greater attenuation even in the pass band that’s why you only want them behind an LNA most of the time.

In my experience the rtl-sdr filtered 1090 LNA and v3 dongle gets you better reception than the FA filter and pro stick plus.

I got the wideband LNA because I do generic SDR stuff mostly, and only just recently ADS-B. For experimenting I’m quite ok with external filters.

@wiedehopf - Coincidentally I just decided to add an external filter to my blue dongle on my “production” feeder. I noticed during my weekly Amateur Radio emergency net that transmitting was completely overloading the ProStick Plus (all of my plane contacts started upticking the age count). Adding the FA barrel filter completely fixed the issue, so it looks like I will always have to have a filter first on my own setup. :slight_smile: