Gain Optimization Script

[Burton_Ped]

I don't have an amplifier. Just a filter to take out the Mobile phone signals.

I'm just struggling to understand what the output from your Graphs programme is telling me. It suggests to me that different gains result in better readings depending on the time of day, but you're correct that I was getting 0% of messages even with a setting of -10.

As an aside, various posts refer to setting the gain at (for example) "38" yet I have read that the only acceptable values are the declimal ones (e.g. "38.6"), so when experimenting, should I be entering 38 or 38.6 as the gain?

[wiedehopf]

-10 in practice usually equals around 55-58, a driver quirk.
next lower gain is 49.6

But it's really not important, if you have 0% strong messages at -10, you don't need to consider any other setting.

[Burton_Ped]

Thanks. I want to be sure that the system is working as efficiently as possible and I'm not missing something

When I was checking a few things yesterday, I noticed that in /etc/default/dump1090-mutability GAIN was set to 20.7 yet procargs in /etc/fr24feed.ini was set to -10. Would this conflict? Should GAIN in dump1090-mutability be set to "MAX"?

[wiedehopf]

Depends how dump1090 is started.

I'd recommend dump1090-fa / readsb stand-alone, this gives much more flexibility than using fr24 to start dump1090.

https://github.com/wiedehopf/adsb-wiki/wiki/Raspbian-Lite:-ADS-B-receiver#feed-fr24-optional

[folkeorg]

Can this measurement script run with readsb or dump1090-fa ?

[wiedehopf]

No it can't.
It's a crappy way to adjust gain anyhow in my opinion as traffic fluctuates too much.
This goes by percentage of strong signals which usually gets you a reasonable setting: https://github.com/wiedehopf/adsb-sc...nd-dump1090-fa

[gabkow@gmail.com]

Hi, I've run gain optimization script and I got worse result than I could imgagine. I use some cheap dvbt usb tuner with driven by orange pi zero. I use self made "spider" lambda/2 antenna and 1m long 75 ohm tv-sat cale type Rg6 (or HD 1000). Location of my receiver is roof of small house in city, about 200m from from GSM/LTE BTS.
My dvbt tunner has built in 20dB amplifier, I have no 1090MHz filter. When I mounted orangepi with tuner on the roof I changed 15m long tv-cable to short 1m cable. After that my receiver saw less aircrafts. When I run gain optimization script result was worse. And I got solution - I changed "gain" string in this script to values "1 2 3 .... 20" and run test 35 times. After that I noticed the best gain for my device is 9. Probably my receiver got too stong noise signal. Now I think about new receiver with built-in 1090MHz filter (Flight Aware or RadarBox) to increase signal quality. So remember, strong signal doesn't mean better signal, try decrease gain when you are localized in the city.

Regards, Gabriel

[adonisone]

Hi, I am working on a project using linux mint 18.1 and ads-b. I need to be able to adjust the gain on this receiver in order to remove noise, so I need to go down about 80%. Can someone post the script / code on how do do so via shell command line please?

I should add... I am using this system in as a test machine while flying in a C172, hence the reason the gain needs to go down a lot! Currently it will not start to log as I think the aircrafts signal is just to strong being inside.

Cheers!

Rob

[wiedehopf]

Consider using this guide for your ADS-B needs.

https://github.com/wiedehopf/adsb-wiki/wiki/Raspbian-Lite:-ADS-B-receiver

The decoder used has a command to easily change gain:

https://github.com/wiedehopf/adsb-scripts/wiki/Automatic-installation-for-readsb

[abcd567]

Hi, I am working on a project using linux mint 18.1 and ads-b. I need to be able to adjust the gain on this receiver in order to remove noise, so I need to go down about 80%. Can someone post the script / code on how do do so via shell command line please?

Gain adjustment method depends on the decoder you have installed. Following decoders are in common use. Which one you have installed?

(1) readsb

(2) dump1090-fa

(3) dump1090-mutability installed by user

(4) dump1090-mutability automatically installed during installation of Flightradar24 feeder


.

[abcd567]

Gain Optimization Script was Updated in December 2021, and was posted on Github, but was missed to post here.

Works on dump1090-fa ver 6.1 and later, on Raspberry Pi OS Bullseye

https://github.com/abcd567a/optimize...main/README.md