My Stats


#1

These are my current stats https://uk.flightaware.com/adsb/stats/user/gazman321

Should I push to get better or should I be happy with these?

I do have quite a lot of out of band noise, so have fitted a saw filter, I also tried the FA filter but that made thing worse.

Currently using FA prostick plus.

Thanks


#2

You are already number one in Flights, and a close second in Positions, in your area. I would open a cold beer, and enjoy the fruits of your work.

Well done!!


#3

Always these people without hills around :slight_smile:

What antenna are you using? Which saw filter are you using?


#4

Did you ask City Hall to move the hills out of the way? :rofl:

The YOW airport has been in the same place since I can remember. A new residential sub-division was built close to it a few years ago. Cheap land, I guess, but who cares, right? The new home owners do not like the noise, and want the airport to re-locate. A reverse case of ‘not in my backyard’.:roll_eyes:

That said, I do blame the city for allowing the construction in the first place.

It reminds me of the environmentally conscious small town mayor that wanted to build a new water ‘tower’ underground, as to avoid visual pollution. When the city engineer told him it was not possible because of the law of gravity, the mayor ordered the city clerk to find out the law number, and to prepare a bill to repeal it.:joy:


#5

Aren’t there pressure reservoirs or boost pumps a possibility? Sure it’s more expensive than using this outdated law that was passed when Newton lived but hey.

Anyway it could be much much worse. If i lived about 1 mile away i might have literally zero reception. I’m already on a ridge but there are ridges nearby which are a little higher in some directions and quite a bit higher in another direction.

That development near the airport sounds like a fabulous idea indeed :roll_eyes:


#6

I got a 1090Mhz saw filter from eBay, was delivered from Hungary. I can’t find the link on there, in my other post I showed the difference it made to my reception. I also purchased the FA band pass filter, it wasn’t as effective.

My antenna I believe is a collinear from the guy that owns another tracking site, it’s a great antenna!


#7

Haha, maybe that’s the problem, he can’t stand that Ashley Vinning to have more positions than him.
Like I said, some of us see this as a friendly competition of sorts :smiley:
I would be tweaking the gain as close as it can be to perfection, if I would be so close…


#8

Colinears are really good. I think i’m gonna buy me a 10m cable with SMA ends already on and try building one myself with 116mm element length for the 0.85 velocity factor.

But as i hear it rarely works so i’ll see it as just a trial.

Anyway i’ve ordered me up the rtl-sdr blog double amplifier/SAW filter, right now i’m running the FA filter and the blue FA dongle.
Not gonna gain much range, i believe my horizon is mostly the limiting factor right now.

Also i think i could level my spider better it’s slightly tilted i think :slight_smile:


#9

Haha :joy:, I do see it as friendly competition!! But also just want to get the best from my kit, trying out new things to see if it improves range, messages etc.


#10

I’d also like to experiment with making antennas. I’m going try and build one soon.


#11

Regarding gain i don’t have the graph package enabled so i use the stats option of dump1090-fa:

Added this:
–stats-range --stats-every 86400

to the decoder options in /etc/default/dump1090-fa (not sure where you add decoder options for the piaware image)

Then i check the stats with
journalctl -u dump1090-fa -e -n2000
or
journalctl -u dump1090-fa -e -n2000 | grep 'power\|gain\|usable'
The second command only shows the results in the following format:

Sep 14 10:42:45 pi dump1090-fa[19286]:   -24.5 dBFS noise power
Sep 14 10:42:45 pi dump1090-fa[19286]:   -11.5 dBFS mean signal power
Sep 14 10:42:45 pi dump1090-fa[19286]:   -0.8 dBFS peak signal power
Sep 14 10:42:45 pi dump1090-fa[19286]:   541316 messages with signal power above -3dBFS
Sep 14 10:42:45 pi dump1090-fa[19286]: 39152975 total usable messages

Quick math tells me a little more than 1% of messages are above -3dBFS which is a good guideline to set gain. That is unless you are under the a final approach or something.


#12

Then I suggest you setup a second station. Leave the good/main one untouched, as a reference, and play with the second one.


#13

@SoNic67 I would like to learn how to tweak the gain to perfection, I have tried the gain optimization script and set the gain for the most messages/aircraft/positions, however, I’m not really sure what is considered perfection, any tips? I also have what is a high level of noise, MAX -13.0 MIN -32.7 AVG -19.6,I don’t know what I can do to reduce this any help, please?


#14

What is your gain now? Higher gain pushes the noise higher, a good preamp has low noise and lets you lower the receiver gain.
I usually tweak it manually, in short bursts, when the traffic is high in the area (not at night, then it can be higher, but I don’t care that much for the few planes).
Change gain, restart the service, look at the local webpage for results (number of planes and msg/s). After they “stabilize” (15 sec or so) I do it again in small increments around that value.
Supported gain values (29) are: 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6

I have the add-on piaware, so for me, those are the commands.
Edit gain:
sudo nano /etc/default/dump1090-fa

Restart service:
sudo systemctl restart dump1090-fa

If you are unsure of the active setting, you can check it with:
sudo systemctl status dump1090-fa -l

I hope you know that, in the command window, pushing the “up” arrow lets you scroll and re-use previous commands in that session, so you don’t have to compy/paste or type in those every time.


#15

What is you average signal level? Without anything to compare the noise to it does not mean that much.

But my gut says: reduce your gain.
These are my stats as output with the dump1090-fa stats commandline option for the last 24 hours:
Sep 15 10:59:31 pi dump1090-fa[2626]: -23.1 dBFS noise power
Sep 15 10:59:31 pi dump1090-fa[2626]: -11.1 dBFS mean signal power
Sep 15 10:59:31 pi dump1090-fa[2626]: -0.7 dBFS peak signal power
Sep 15 10:59:31 pi dump1090-fa[2626]: 1283806 messages with signal power above -3dBFS
Sep 15 10:59:31 pi dump1090-fa[2626]: 81844041 total usable messages

So maybe reduce the gain two steps and see if you can increase your number of positions.
Of course it might also reduce the range but without trying you won’t know :wink:

Ah and i would change it and leave it for a full week then compare it to the last week of stats on yourflightaware page.
Short term message rates are unpredictable for me.


#16

I’m currently at 48.0, have tried a few different ones, anything under 38.6 i start loosing planes/messages. In the busy time here I normally see around 250-280 planes, I have seen up to 312 at one point, and anything up to 1700 msg/sec, not sure if im hitting the limits of my Pi3B+ with dump-mutability.

In putty/terminal the up arrow is a god send, not having to retype or copy and paste everything again!!

I’ve attached a screenshot of my graphs, I am still a noob at adsb feeding and I only have a basic understanding of the data that is produced.


#17

You are having much more plane traffic than me. That might be the limitation in your case.


#18

Raspi is no limitation, why would you think so is the CPU maxxed out? I doubt it but you can check.

Anyway go to 42.1 gain and check back tomorrow with a new screenshot :wink:

If you lose range you will see it best in your flightaware stat page.

For example currently you have 509 positions reported at 200nm+
If after changing to 42.1 that number changes to 0 you know you have reduced gain too much.

You should set the lowest possible gain so you don’t lose messages that are too strong while still receiving maximum range.


#19

The receiver can be maxed out with the ADS-B protocol. Like any data link, it has a maximum throughput.
He is already close to that max at 1800/sec.


#20

I always thought that the limitation was the USB, not the CPU. My CPU is roughly around 12-15% usage.

Change made to 42.1, will repost graph tomorrow.

Thank you all for your help!