Checking noise levels?

FlightAware ADS-B Flight Tracking
1

Hi, I recently setup piaware on my linux host. It’s working but I want to see how much noise and other stuff I am picking up. I am a radio ham and operate on other bands 3-30Mhz, 145Mhz and 433Mhz (approx). Ideally I want to monitor the dump/sdr at the same time as I tx on other frequencies to see how much interference is being picked up.

My aerial is on a triplexer and is shared with a radio on 144Mhz.

So ideally something I can run that will display noise and good signals at the same time.
Thanks
Mike

2

 

 

Spektrum - How-to Speedily Scan RF Noise in band 24MHz ~ 1800MHz

 

 

 

1 Like
3

Just transmit for a minute and check graphs1090?

2 Likes
4

Thank you, I didn’t even know that existed but looks like just what I need.
73
Mike

6

How to remotely access Dongle Plugged into RPi from Windows PC over TCP

(1) https://discussions.flightaware.com/t/spektrum/87174/2

 

(2) https://discussions.flightaware.com/t/howto-run-ads-b-receiver-ais-receiver-on-same-rpi/85040/134

 

7

I’m happily using 40w on FT4 and FT8 and have the Flightaware (light blue) filter in line, check your Skyaware page whilst you are TX’ing and see if any planes ‘drop’ off.
I could see the odd distant one drop off.
I also use a basic filter I got from AliExpress which works too.
Not scientific but hey, it worked for me.
The advice given above is more reliable than what I did…
73

8

For some quick results, run this one-liner on your rpi:

grep -sh /run/{dump1090,dump1090-fa,readsb}/stats.json -e '' | jq '.last1min.local | ((.accepted | add), .strong_signals, .signal, .noise)' | xargs -n4 echo | awk '{printf "\nStrong message rate: %.3f\nSignal: %.1f\nNoise: %.1f\n", $(2) * 100 / $(1), $(3), $(4)}'

It will output something like this:

Strong message rate: 1.499
Signal: -10.2
Noise: -25.3

Make sure you have packages jq & findutils installed.

2 Likes
9

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Screenshot_20240706_091527_Termux
Screenshot_20240706_091527_Termux1080×461 141 KB

10

You’d look at last1min instead of total though?

1 Like
11

You’re right, way better. Fixed it in the original post.

12

Using updated one-liner command, twice with a gap of 30 sec between them.

Click on Screenshot to See Larger Size

Screenshot_20240706_152917_Termux
Screenshot_20240706_152917_Termux1080×817 160 KB

 

13

What sort of figures should I be looking for? Which is preferable?
I seem to be getting like:-

Strong message rate: 9.934
Signal: -8.2
Noise: -23.4

Then 10 mins later

Strong message rate: 0.828
Signal: -9.8
Noise: -26.3