Added filter. Gained flights on FR24, dropped on flightaware

[gumbi4u]

Hey guys,

Hope some of the experts can help.

Running a flightaware pro plus stick with black flightaware antenna. Cean pi install with piaware main software and fr24 feeder. Been getting really good hits with this setup. Thought I’d add a AirNav RadarBox 1090 MHz ADS-B Filter behind it since I’m in the NY/NJ metro area. Now with the filter I’m getting a weird phenomena. On piaware the total aircraft and positions dropped by almost 15%. Yet on fr24 I gained nearly 20%. Its pretty significant. You can see the results immediately after installing the filter. I remove it and everything evens out again.

Also noticed over all everything has dropped. Maybe due to the bad weather in the area.

I might just yank off the filter and leave it be. Maybe I’ll try the uptronics preamp with filter.

Thoughts?

[wiedehopf]

@gumbi4u

AirNav RadarBox 1090 MHz ADS-B Filter

That’s not a product as far as i’m aware.
Are you talking about the green USB receiver they offer?

Edit: … seems there’s a new product, nevermind this question.

[LawrenceHill]

@gumbi4u

AirNav RadarBox 1090 MHz ADS-B Filter

@wiedehopf

That’s not a product as far as i’m aware.

I think it’s this one:
https://www.amazon.com/AirNav-RadarBox-1090-ADS-B-Filter/dp/B082WR1SDF

[wiedehopf]

@LawrenceHill

it’s this one:

Just saw it in another thread, wasn’t aware of it.
No clue what the passband is like.

@gumbi4u you really want local graphs to make comparisons, some aspects aren’t shown by the online stats.
GitHub - wiedehopf/graphs1090: Graphs for readsb / dump1090-fa / dump1090 (based on dump1090-tools by mutability)

[gumbi4u]

Yep that is the one.I wanted to get the flightaware blue tube version but its not available. Thought I’d give this one a shot.

[foxhunter]

Wohoo, they made the filter “blue”. Good marketing

[abcd567]

I have ordered this filter directly from AirNave site (due to lower shipping cost and no sales tax, as compared to Amazon).

Awating delivery. Will put it on trial run when delivered, and post results.

[gumbi4u]

Nice! Looking forward for the results.

The past two days after introducing the filter into the setup, It seems its a drop between BOTH platforms. Its just FR24 is showing a slight “advantage” over FA.

[abcd567]

What is your gain setting for dump1090?
Which one you have, dump1090-fa or dump1090-mutability?
Which image are you using (Raspbian image, or Pi24 image, or Piaware SD card image)?

[gumbi4u]

Running a rasbian image. Dump 1090fa. Gain is still at default -10. Before the filter, I did play around with the settings and +40 gave the second best results to the default setting.

[Dxista]

@hdtvspace

Everytime I get a lower msg rate and aircrafts, if I connect this airnav filter.

@hdtvspace

And as a test comparing the green airnav usb stick vs. the FA pro stick plus: The FA pro plus stick is always much better in message rate and aircraft.

@hdtvspace

I will buy an 2nd FA Pro stick plus. In my eyes is the green airnav usb stick a bad deal.

My experience exactly. We must have received defective units. The RadarBox stick cost the same as the FA Pro Plus on Amazon Canada, so the choice is an easy one for me.

Regarding the RadarBox filter, I was thinking of getting one, no more.

My experience so far is:

1. for quick and cheap - FA Pro Plus;
2. a little more money and trouble - RTL-SDR Blog v3 and RTL-SDR Blog LNA+filter combo.

To make option 2 easier, I’m considering the NooElec SmarTee, instead of the RTL-SDR Blog stick, because of the always ON bias-tee.

[SerVIP]

I had exactly the same problem… Installing the filter substantially reduces the number of aircraft detected… It’s not very useful…

[foxhunter]

Which filter did you use? Did you also adjust the gain setting?

[SerVIP]

AIRNAV RADARBOX 1090 MHZ FILTER

Use 49.6 as gain adjustment

[wiedehopf]

@abcd567

Awating delivery. Will put it on trial run when delivered, and post results.

How did the Airnav SAW filter perform for you?

[abcd567]

@wiedehopf

How did the Airnav SAW filter perform for you

I have not used it for actual reception, but have tested it. Please see this post:

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

RadarBox24’s 1090 Mhz Filter Setup [20200312_010138] Scan 1 of 2: DVB-T Generic Black - without Filter [DVB-T Generic Black - without any Filter] Scan 2 of 2: DVB-T Generic Black + RadarBox24 Filter [DVB-T Generic Black RadarBox24 Filter]

[wiedehopf]

@abcd567

I have not used it for actual reception

But that’s the interesting bit

The scans won’t adequately show the attenuation of the pass band

[abcd567]

OK, replaced FA Light Blue 1090 Filter by RB24 1090 Filter.
All other things (hardware / software / --gain 48) remain same.

FA 66cm 1090 Atenna in window >> 30 cm RG316 pigtail >> 1090 Filter >> FA ProStick Plus >> 1 m USB extender cable >> OrangePiPC

FA Filter: Up to 17:40 EDT
RB24 Filter: From 17:40 to 18:20 EDT
FA Filter: From 18:20 EDT to End of graph

[wiedehopf]

Can’t argue that it’s more insertion loss.

But the way some people said it was resulting in way less aircraft … seems exaggerated.

Anyhow that’s how it is with filters … if you don’t REALLY need them, they often are not an improvement.

[abcd567]

@wiedehopf

But the way some people said it was resulting in way less aircraft … seems exaggerated.

My case is exactly opposite.
I see almost negligible aircraft when I remove filter and connect antenna directly to the ProStick Plus:

NOTE:
Every time I removed and inserted the Filter, I made sure that all connectors are fully tightened, so the drastic drop is not due to loose connection. Actually I have several Cell/Mobile phone companies antennas on my building as well as adjuscent buildings, which causes overload of the LNA of ProStick Plus, and its SAW chip being located after the LNA, cannot protect the LNA from overload.

I hope in next version of Pro Stick Plus which is due to be released shortly, they will either relocate the SAW filter between LNA and input SMA connector, or may be add one more SAW between SMA connector and LNA. Let us wait and see.

1. Up to 21:20 EDT > Antenna connected to Pro Stick PLUS through FA Light Blue Filter

2. From 21:20 to 21:50 EDT > Antenna connected to Pro Stick PLUS directly (Filter removed).

3. From 21:50 to 22:00 EDT > Antenna connected to Pro Stick PLUS through FA Light Blue Filter

4. From 22:00 to 22:25 EDT > Antenna connected to Pro Stick PLUS directly (Filter removed).

5. From 22:25 EDT to end of graph > Antenna connected to Pro Stick PLUS through FA Light Blue Filter