FlightAware Discussions

Announcing the new 1090 MHz only bandpass filter!

#1

FlightAware is excited to announce the availability of a 1090 MHz-only bandpass filter for the ADS-B community outside of North America. This is something many of you have asked for. The filter we’ve offered in the past wasn’t great at blocking GSM mobile phone interference that can be found outside of North America. This new filter is an economical bandpass filter option that provides better attenuation of 950 MHz GSM. Those of you building PiAware sites in urban areas or other areas with 950 MHz mobile phone interference (found outside of North America) may find this very useful. We are pleased to offer this through our retail product launch partners in Europe: ModMyPi and Moonraker and they are available for sale today. We hope to add more retail distribution partners in other areas of the world going forward.

Tech specs:
Pass Band Insertion Loss: <2.5 dB
Pass Band Frequency Range: 1080-1100 MHz
Stop Band Rejection: >30 dB
Nominal Impedance: 50 Ohms
Female and Male SMA connectors
Approximate dimensions: 1.5 inches x 2.25 inches

1090Filter1
You can identify this bandpass filter easily by its dark blue label.

And for our users that like a comparison, the previous filter:

The 1090 only filter:

13 Likes
Changed USB Dongle. No data on PiAware Skyview
Changed Antenna filter
Help need on installation and performance
pinned #2
#3

Great!
This was badly needed.
Well done Flightaware :+1:

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#4

Very nice economical option! Well done. Is it a LC filter design?

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#5

Great news, I will replace the filter I have on my outside receiver as soon as the weather allows me to drop the mast.

#6

Yes, it is a LC filter design.

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#7

This new filter is particularly useful for countries where mobile/cell phones use GSM900.

The original FA Filter could not eliminate signals in this band, but the new version has a narrower pass-band, and can eliminate signals in this band also.

GSM-900:
This band of frequencies is used for mobile/cell phones in most parts of the world (ITU-Regions 1 and 3): Africa, Europe, Middle East, Asia (apart from Japan and South Korea where GSM has never been introduced) and Oceania.

GSM-900 uses 890 - 915 MHz to send information from the Mobile Phones to the Station on Mobile Tower (uplink), and 935 - 960 MHz for the other direction (downlink),

GSM-850 (also known as GSM-800):
This band of frequencies is used for mobile/cell phones in most of North, South and Central America (ITU-Region 2)

GSM-850 uses 824 - 849 MHz to send information from the Cell Phone to the Station on Mobile Tower (uplink) and 869 - 894 MHz for the other direction (downlink).

3 Likes
#8

Thank you for this, just ordered. I have quite a few cell towers in my area running all sorts of frequencies. In particular, a 700/850/1800 MHz Telstra tower 100m down the road plus an Optus/Vodafone tower about 1km away running 700/850/900 MHz and many higher frequencies. Will be interesting to see if the new filter improves my PiAware stats.

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#9

I have got a question. I am hosting one of your Flight Aware receivers, I believe it is revision G6 or something. Does the receiver have a built in filter of any kind or not?
And if not, do I need to put such a filter?
I can’t wait for the comparison of the two filters, since my other feeder has one of the older kind of filter, and my location is in Europe.

#10

Pretty sure there is a Mode-S Beast built into the blue Flight Feeders, which do have filtering: https://wiki.jetvision.de/wiki/Mode-S_Beast:System_Design

Maybe your old generation Flightfeeder does not have GPS and may would even be compatible with a filter but it still doesn’t need one.
On the units with integrated GPS antenna the filter would disrupt the GPS signal coming from the antenna.

Anyway when you have excellent coverage up to very high distances it is normally a sign that you don’t need any extra filtering.

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#11

That FlightFeeder is seeing 5500 planes at 250+ miles. I think you are golden…

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#12

The G6 doesn’t have the GPS receiver.

#13

Maybe you have meant 5500 positions?

#14

Yeah, sorry. Anyway some here would be very happy with that range :wink:

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#15

A scan someone posted in FlightRadar24 forum:

  • Top scan: Without any filter.
  • Bottom scan: With “new 1090 MHz only” filter

.
filters

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#16

That’s an impressive result!

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#17

Aviation is vitally important particularly in this modern age of scientific and technological advancements and so is the supportive efforts of flight tracking and navigation systems being introduced or controlled by FlightAware. I appreciate the efforts that FlightAware is making in order to make aviation safer and better in all respects. Regards!

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#18

Any idea if and/or when this filter will be available in North America?

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#19

It seems that in the UK most of the mobile phone companies use 800 MHz and much higher frequencies. Therefore, would it be better to use the ‘older’ pale blue filter rather than the ‘new’ dark blue one to block out any potential interference?

Thanks

#20

The described property is normally the passband, so what gets through.
The newer one lets through a narrower band of frequencies.

So the new filter is better in blocking non ADS-B frequencies.
(The old one was designed to let 978 MHz, UAT pass as well resulting in some problems with the 900 MHz mobile phone band in Europe)

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