FlightAware Discussions

Pro Stick Plus combined with External SMA Filter?

Hello, I live in an urban environment and recently setup a PiAware receiver consisting of the recommended indoor antenna, blue Pro Stick Plus receiver with built-in filter, and a Raspberry Pi 3 Model B. I also ordered the FlightAware 978 - 1090 MHz external in-line filter just in case.

My receiver is running wonderfully, however, I was wondering if it would be beneficial to add the external in-line filter to my setup. I know that the Pro Stick Plus has it’s own filter, but wasn’t sure if there would be a reception related advantage while living in a large metro area to including the external filter as well.

Thanks in advance!

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Do I Need A Filter?

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Thank you for the link, most helpful. I will perform the scan per the option 1 instructions and analyze the results.

Is there any harm (such as reduction in signal strength) by using both the built-in filter and the external filter?

The external filter will add insertion loss, but it is small (< 2.5 dB), and is easily compensated by the 18 dB LNA (low noise amplifier) built into ProStick.

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From https://www.amazon.com/ADS-B-Dual-1090-Band-Pass-Filter/dp/B010GBQXK8

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You’ll just have to try what works better.

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I experience more simultaneous aircraft being tracked with the in-line filter in use!

In my opinion the FlightAware instructions should mention the fact that reception may improve if the in-line filter is used in conjunction with the blue Pro Stick Plus.

Within 10 miles, you are almost the lowest performer.
By the look of your setup, you are only running a mag-base antenna(?), in which case additional filtering is completely unnecessary.

With respect, your site hasn’t been online long enough to know what ‘normal’ is.

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That’s not necessarily true.
With strong interference, even a bad antenna will pick it up.
The antenna might even be tuned for the interfering signal.

You need some sort of statistic to really check differences between setups and compare two weeks day by day.
The FA statistics aren’t too bad for that, you can also use these graphs: https://github.com/wiedehopf/graphs1090#graphs1090

Even comparing two weeks can be misleading, traffic fluctuates quite a lot.

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That is a good start, but there is no substitute for a pair of receivers side by side: One as a reference and the other to play with.

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Agree. Either my second FA antenna is bad, or the RadarBox stick is not as good as the FA Pro+ stick. I gave up trying to optimize that one.

I was thinking about using a NooElec Smartee with the RTL-SDR Blog ADS-B amp/filter combo, but will wait for the new upcoming FA stick.

If you compare the pattern of the planes that you tracked
Planes

with the planes one of your close neighbours tracked over the same period

Planesnearby

the change in Aircraft Reported seem to track so it is reasonable to assume that the increase you have noticed is due to increased aircraft rather than an increase in performance of your receiver due to adding the extra filter…

There are very few users on this forum who use multiple filters and those that do are in extremely harsh RF environments. I suspect that if Flightaware started mentioning using more filters it may be seen as a cynical attempt to sell more kit which is NOT their usual MO.

There are a gazillion posts on this forum to help you optimise your station for what you want to receive; ie more range, more aircraft, more position reports, more ground vehicles etc. etc.

If you need assistance, just ask here and many other users will be pleased to assist.

Enjoy,

S.

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Thanks for the input everyone. To start with, I’m going to upgrade the small magnetic base antenna to the FlightAware indoor/outdoor antenna. Unfortunately in our current condominium, mounting an outdoor antenna is not possible, but hopefully the larger indoor/outdoor unit mounted in a window with a good view of the sky will improve my reception performance.

Even if indoors, the FA antenna will sure considerably improve reception compared to the magmount.

If you have strong mobile/cell phone signal in your area, adding a filter will improve further, but first thing first, get a Flightaware antenna and try it. Later you may consider adding a filter as well. After you install FA Antenna, perform the scan proposed in thread “Do I Need A Filter”.

Flightaware antenna installed inside my apartment

CLICK ON IMAGES TO SEE LARGER SIZE

Will FA be introducing a European Pro Stick Plus with the tighter 1090 filter integrated?

Keep in mind that the internal and external filters are not the same ‘technology’.

The built-in filter is of the SAW type, not much can be done there.

The external filter is of the LC type, easier to change the parameters.

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Well you can put LC high pass in front of the LNA to reduce anything below 1 GHz, which is generally what overloads the LNA.

Then the SAW behind the LNA can clean up.

So yes you can integrate something like this (as it is integrated in the rtl-sdr triple filtered LNA).

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The question was:

“Will FA be introducing a European Pro Stick Plus with the tighter 1090 filter integrated?”

I interpreted that based on the release of the ‘European’ dark blue filter. It was easy to fine tune that, not as easy with integrated saw filters.

Doable, yes, but cost is always an issue. For those with no budget constraints, ‘better’ options are already available, no need to wait for FA.

I’m looking forward to FA’s new stick, but not at any cost.

Shouldn’t you run this at much lower gain or somehow attenuate the noise source?

I have deleted my various posts regarding “RF Scan by noise source”, and have created a new thread combining all these posts at one place.

RF Scan of Various Combinations of Dongles, Filter, and LNA

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Had some free time yesterday. The RadarBox stick is now inside a big cantenna that will be emptied tomorrow. :joy:

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