Optimize Gain - which would you chose

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sudo apt update
sudo apt install git

cd ~/
git clone https://github.com/jprochazka/adsb-receiver.git

cd ~/adsb-receiver
./install.sh

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When it starts presenting options (update, dump1090, feeders, web portal), continue saying <NO> to everything till it offers “Web Portal”. Say <YES> to it. When Web Portal Installation starts, it will ask “Do you want Advance Options?”. say <NO> to it and installation of Web POrtal will start. The RRDTOOLS are part of Web Portal.

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2 Likes

If you ever try that setup again test 25 and 30 to see if it’s any better :wink:
Oh and make sure to use the filter.
Not sure it will be any better though there are cases where the good antennas catch some mobile signals or something i guess which then overloads the prostick LNA at least that’s my theory on the problem.

well regarding mobile signals I am surrounded by a ‘forest’ of mobile towers 900/970-80/2100mhz
on the other hand th FA filter helps a bit, but not many 800/870mhz around.
I elected to keep same gain as constant, to avoid adding another variable and
didi that with the filter too. same poor result. seems prostick plus likes more 75ohm sat cable and has a filter of its own.

the FA filter on the v3 does make a difference.

OK, after changing Gain from 48 to 38 an hour ago, some improvement in dBFS (see last hour).
I will now change Gain to 28 and wait another hour to see how things go.

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thanks @abcd567. one thing though. is there a ‘rule of thumb’ regarding noise level vs gain setting ? If I interpret correctly, noise is blue/magenta line between 17.5 and 29.3 ?

I mean you need to test with less gain if you switch to a higher gain antenna. That’s not introducing another variable it is just necessary i’m sorry to say.
Anyway it might not change things.

The noise level is not that relevant to setting gain. Keeping the red spikes down is a good rule of thumb :wink: You did that by staying below -3dBFS with you peak signal.
Now i’m not avoiding the red spikes completely as you can see here:

will give it another shot :grinning: however as I said I tested both configs at 37.2 one with and one without filter and results were poor. have to wait though tomorrow, peak hour traffic 1000-1200 utc.

Was the range worse or just the message rate very low?

Anyway you can just tune the gain and make the signal graph look like the current one maybe the green a few dB more and then compare.

With Gain down from 48 >> 38 @ 9 am >> 28 @ 10 am

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I guess your situation is kinda special you will never get the planes close in and the planes that are barely visible from your apartment and far away in the dynamic range of the dongle.

Do you actually notice close in planes disappearing because of overdrive?
I wonder how much red (reserved for signals > -2dBFS in new version) would be on the signalview. (with a gain of 38 for example, with 28 it would be very little red i suspect)
A little back i caught this guy. Lost him for 5 seconds or so because the signal was too strong but that’s fine.

well, this isn’t going well so far…
after the “git clone GitHub - jprochazka/adsb-receiver: Create your own ADS-B receiver and web portal.
i get lines that say
Cloning into adsb-receiver…
remote :Enumerating objects: 24, done.
remote: Counting objects: 100% (24/24), done.
remote: Compressing objects: 100% (20/20) done.
remote: Total 6498 (delta 10), reused 9 (delta 4), pack-reused 6474
Receiving objects: 100% (6498/6498, 2.20 MiB I 3.90 MiB’s, done
Resolving deltas: 100% (4003/4003), done
-bash: cd /adsb-receiver: No such file or directory

@retman1222 don’t do cd /adsb it’s just cd adsb-receiver without the /

with the / in front it means relative to the “drive” if you will not relative to the current directory.

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If you look to my post carefully, it is NOT cd /adsb-receiver
It is cd ~/adsb-receiver . You missed ~

Or simply use cd adsb-receiver (without /)

hello abcd567…i have a new monitor (LG) and when i type the tilde symbol in it shows up as some symbol i have never seen…the same keyboard on two other monitors shows a proper tilde…so i am afraid i messed up the first round…sorry for the trouble

can i used cd in place of cd~/ as well

@retman1222
use

cd (enter)
ls (enter)
cd adsb-receiver

and show the output if it’s not working :slight_smile:

the first cd ~/ is normally not necessary.
but just using cd is equivalent to cd ~/
Both commands change to the users home directory.
There should be no need to do the git clone again.
If you are unsure how to proceed post the output of

cd
ls

Actually, when a plane signal goes above -3…-2 dB it won’t usually “disappear” by themselves, but it will also overload and drown the weaker signals.
You can still hear the drumbeats when they are so loud that your ears are hurting, but you won’t hear in the same time the wind shuffling the leafs.
Dynamic range is constrained on bottom by the noise level and that is the limiting factor.
This is how I like my signal:

ok, all installed and i have the line
pi@piaware:~/adsb-receiver $

what command do i use to run the program ? (sorry, as you can tell i am very new to linux)

did you do the

./install.sh

yet?

If that is finished you can visit the

http://192.168.X.X/install/

to finish it. (substitute the IP address of the pi)

Open your browser and type following address
IP-of-Pi/install/

Then follow instructions. It will ask for user name and password. write these on a paper so you dont forget. You will need it in next step.

After completing, go to this address
IP-of-Pi/admin/ and make any changes you want and at the end click save button.