Filter 1090 Feedback

FlightAware ADS-B Flight Tracking
1

Hi Guys,
yesterday i started to use the 1090 filter delivered by flightaware.
I’m using a dvb-t stick + raspberry to receive ads-b messages but i have a GSM repeater near my site:

https://s16.postimg.org/w7x83uli9/IMG_20161103_094000.jpg

It doesn’t seem to be a big problem because i receive many aeroplanes:

https://s11.postimg.org/yv3h3wrm7/senza_filtro.png

The reality is very different: i’m a lucky guy who lives between three airports and has a clear skyline around me.

In fact after using the filter i stated to receive more aeroplanes and farther signals

https://s11.postimg.org/wxbx9nda7/filtro_2.png

Without filter i received 66 aeroplanes and 400 messages per second, with the filter 81 aeroplanes and more than 600 messages per second.

The filter may be useful to improve your receiving system if you live in urban area or near gsm repeater.

I hope that my experience can be useful for you.

Best
Vince

2

good to know, thanks.

Sent from my SM-N910F using Tapatalk

3

I was always concerned with cell towers within a few miles of my house so I bought a filter with my prostick and have been running it that way for months. Tuesday I removed the filter and have so far seen what appears to be a slight increase in activity and range. I guess you don’t really know if you need it or not without trying both ways.

4

I have tried many setups. My experience is that with high gain antennas like FA antenna, generally Filter improves reception, while with low gain 1/4 ground plane antennas (Spider and Cantenna) filter does not make any noticeable improvement.

5

Hi Guys,
i agree with you. Unfortunately you cannot know if you need or not the filter without trying it.
The filter introduces insertion loss. If you live in a noisy area, the improvement of signal/noise ratio given by the filter improves your signal reception despite the insertion loss introduced.
But if you have already a good S/N ratio the filter introduces only losses without any benefit.

I guess that the near signals are not improved by the filter because they are already strong. It should be useful with far signals.
If you use a poor antenna maybe that you don’t receive any signal that can be improved by the filter, instead the near signal could be received worse or not received anymore if your antenna is not good enough.

This is my opinion.

More feedback are appreciated.

Best
Vince

6

My setup without a filter 2 aircraft, with (Cavity) filter 200 aircraft.
I am surrounded by apartments with cell/mobile towers and within 15NM of 3 aircraft radars (KLGA,KEWR and KJFK, not sure about KTEB).

I am sure that every setup is unique and will need tuning and experimentation.

7

Which antenna are you using?

8

I use the DPD 1090Mhz (I also have both FA Antennas and some directional antennas)
dpdproductions.com/page_vhf_air.html#adsbout
with LMR400.
I currently use a radarcape but have also tested it with the FA 1.0 pro stick.
My pro stick plus arrived last night. I will test it on my basement units sometime soon.

This is the cavity filter I use
shop.jetvision.de/epages/6480790 … ucts/71010
It has a really narrow bandwidth, however, it is 4-5 times the price of the FA filter.

In my opinion, the pro stick plus with a decent antenna system(coax and antenna) and height is the best value for money.