Thoughts on Maximum RSSI vs Maximum Planes etc

FlightAware ADS-B Flight Tracking
1

As I try to tweak my ADS-B setup, and I am trying to figure out what is important to maximize.

Is it lowest minimum RSSI (currently around -30) ? Maximum messages / sec ? Maximized planes ? Or 5% -3dBFS ?

My goals … to maximize the performance of my setup. A bit about it, using RadarBox Green USB 1090 dongle, FlightAware blue 1090 filter (I find both filters gives me a higher message / sec), Uputronics 1090 LNA / Filter, 1090 antenna about -9 dB gain up maybe 20 ft from the ground, LMR400 coax of < 30 feet, Raspberry Pi 3b running PiAware.

My goal is to maximize the ability to track distant planes, I will admit that it excites me to get more range rather than the planes that are reasonably close. But I am looking for a reasonable compromise to try to get both as best I can.

I do not live by an airport, more in the center of a large urban city. So I am aware that buildings etc may be an issue.

I have my gain set to 32.8 and am going to leave it there for a bit to see how it goes.

I am kind of new, so be kind as I will admit I don’t begin to know it all and am trying to learn.
Kevin

2

Use 2 receivers.
One receiver + dongle +antenna for far away planes (gain set high)
Other receiver + 2nd dongle + 2nd antenna for nearby planes (gaion set low)
Then mix output of both receivers to display on a mixer’s map.

However Flightaware recommends not to feed them mixed feed. Use mixed feed only for local display. For feeding Flightaware, use independent piaware data feeders for each receiver, with each piaware data feeder using a different feeder-id.

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Thank you. I have some extra gear, like antennas etc but the Raspberry Pi and maybe a filter is all I would need for a 2nd setup. As my location is tough, the close one, would get a bit worse of an antenna location … but I still should be ok.

The ‘mixers map’ concept is a bit foreign to me, is there something you could recommend ?

I have been reading about an Airspy instead of a dongle. I already use an Airspy for my other hobbies. But for ADS-B is there a benefit to go to a such a unit ? If so … what model do people use ?

4

You can install a mixer on any of your RPi which is already running dump1090-fa and feeding Flightaware or other sites. You simply need to run following bash script in Pi’s terminal / PuTTY

sudo bash -c "$(wget -O - https://github.com/abcd567a/mixer/raw/master/install-mixer.sh)"

The mixer installation script creates second copy of already installed dump1090-fa with name “mixer” and its dedicated map at ip-of-pi/mixer/ This does not interfere in any way with existing dump1090-fa and piaware.

 

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Right, but isn’t your ranking on FlightAware based on each individual feed, not on the combination of the two (or more) feeds?

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I will look into it when the time comes. Appreciate the info.

7

Yes you are right.
If flightaware would allow mixed feed, then it would be good for operators of multiple receivers. I dont know/understand why Flightaware recommends NOT to use mix feed. Flightaware staff @obj may explain it.

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It depends ho you look at it.
There is a feeder ranking but also a user ranking.
In the feeder ranking the most effective units are on top.
In the user ranking it is the total amount of data.

For example, my most effective feeder is on place 2320 but my user ranking at the moment is number 4 due to having 15 sites in total.
In the ADSB stats there is a top sites and a top user table based on the last 30 days.
So you have a feeder ranking and a user ranking.
The postion in the stats page on top is based on the user ranking

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This is my 24 hour with my gain set at 32.8. It doesn’t seem too bad. I am pretty happy with my range. Being new … if anyone has suggestions, please let me know. I just bought all the stuff for a 2nd setup today, so should be a week or so.

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Ok, I didn’t know that. Thanks.

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User rankings are at the top of the web page. Each receiver / site gets rankings in the "30-Day Site Ranking " graphic. Have fun out there.

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Yeah, I guess I wasn’t paying attention to the difference in the terms being used there. It makes sense now.

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As I wait for the next 3 hours to see how my 24 hour graph looks like, I am wondering if there is some way to find out the ‘total number of messages’ and ‘total number of aircraft seen / tracked’ on a given (selected) period of time in graphs1090 ? (at least for the small time periods, as for the longer times it would not make sense, maybe max 24 hours)

Though I could run SkyAware for 24 hours to see the position total, that would tell me the impact of the gain setting, but really I would just prefer if graphs1090 did it.

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I have seen people with data, but I am not sure how they got the data.
Thanks
Kevin

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Do you not just bring up graphs1090 in your web browser?
e.g. Your receiver IP address/graphs1090/

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Yes … but you cannot see a total.I think I am going to run SkyAware for 24 hours and see the position history data. The stats page would probably be ok, if you changed your gain at midnight.
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My 24 hour graph. I am going to drop the gain a bit to 32.8 to try to get down to 5%.

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Understood. So what is the gain set to now before moving down to the 32.8? I see you are currently at 7.2%.

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I was at 33.8 before. Another day to see how it works out. I am going to do another setup in the next week or so, this is the close low gain setup. Other one will be higher gain for more range.

I am going to use a splitter and use the same antenna, but 2 separate Raspberry Pi setups.

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