FlightAware Discussions

Changed Antenna filter

I changed my antenna filter from 1090 to 1090/978 and now have little Green,yellow and orange airplanes.

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When you say “1090” filter, do you mean the Light Blue or Dark Blue filter?

Do you mean “small planes” or “few planes”
(I assume this is Skyview?)

I did not notice the color diff, But the one labeled 978 and 1090.
I ment ,a few small planes as opposed to airlines above 18,000 ft.

Just trying to work out what you are using.
The original filter was labeled 1090MHz, (light blue) but is in fact the same as the current 1090+978MHz filter (also light blue).
Recently a narrow band 1090MHz filter has become available (dark blue).
The insertion loss is about the same (at 1090MHz), so really shouldn’t make a difference, but if you’ve replaced like-for-like, the problem is definitely elsewhere.

My 1st Filter is labeled 1090, The new one is labeled 1090/978. Same FA orange stick and the new filter yielded low altitude flights that I have never seen before

Mmh, it is still not clear, is it? How old is the “1st filter”?

Product cylce wise, this is the first FA filter:

This is no good eg in Europe, compared to eg the US, because of different mobile phone frequencies.

This is why they rebranded it as a UAT/ADSB-filter. It is the same filter, and has kept the light blue colour:

Also, they created a new one, which is better for many non-US locations:

It’s pretty clear, the dark blue filter was never / is not sold in the US.

Anyway maybe the new label gave moral support to the receiver :slight_smile:

Ah, ok, I did not know the dark blue one is not sold in the US. So the OP is basically using the same filter, the only difference is that the label has changed? Maybe the older one is defective?

Maybe it’s just flights that didn’t have the UAT transponder previously?

It’s not like GA traffic follows rigid patterns either.
Also maybe obj made some improvements to the UAT decoder making it better at picking up the signals.

I am very confused, the 1st filter is clearly marked 1090, Which means to me that it is tuned to pass 1090 Mhz. The 2nd filter is clearly marked 978/ 1090
It on top of my mast and I am not about to take it down to check. Bottom line , I am seeing traffic that I have not seen before. Maybe at my age (86) I am seeing things that are not there!

According to flightaware both light blue filters you have pass 1090 MHz and 978 MHz.
They relabeled it when they introduced a new product which only passes 1090 MHz for the non-US market.
(In the US the GSM900 band which goes to 960 MHz is not used, thus they designed the filter so that it would pass 978 MHz as well because they already knew about UAT)

We’re just curious, maybe FA mixed something up and the filters are actually different who knows but one would have to measure both filters you have to come to a conclusion and i’m not THAT curious!

No matter congrats on the new traffic, no one was insinuating that you are seeing ghost planes :slight_smile:

The 1st filter is a 1090 bandpass filter with a wide bandpass. It does pass 1090; it’s also wide enough to pass 978.

The 2nd filter is the same thing with an updated label.

The dark blue filters mentioned above are a 1090 bandpass filter with a narrower bandpass that blocks 978 (and also the GSM frequencies which can cause interference in Europe etc)

The newer labels have the approximate bandpass edges on the label (e.g. the light blue one passes ~ 980-1150MHz, IIRC those are the -3dB points so there’s not a ton of attenuation at 978 even though it’s slightly outside the bandpass)

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SOURCE:
https://www.rtl-sdr.com/review-flightaware-ads-b-antenna-and-filter/

Flightaware 1090 Mhz Filter (now renamed to 1090/978 Mhz Filter)

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SOURCE:
https://www.rtl-sdr.com/new-product-from-flightaware-a-1090-mhz-bandpass-filter-for-the-rtl-sdr/

filter_data

What version of Piaware are you running?
Just wondering if you are now receiving 978MHz instead of 1090MHz
(the RTL chip is impressive, but can’t receive 978 and 1090MHZ at the same time)

This graphic makes it a little more clear to me

I think I have it figured out now. Part of my confusion is that I built a STRATUX receiver for my plane and it has 2 receivers and 2 antennas plugged into the Pi. My thinking at the timeof the observation of the NEW low altitude planes was that since they were low they had to be UAT. Now I realize it could be a Boing 747 at 1000 feet still broadcasting 1090.
Sorry I caused the confusion!

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I wasn’t confused, but I am now.
You have a two band STRATUX in your plane and a singe band on your house?
Which unit are we discussing?

I think I had better give up. I just am not very good at explaining myself. We were discussing the Light Aware installed at my house, and I was trying to explain how the Stratux influenced my thinking .
I better just drop it!

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