ADSB Signal Graph

Hello, just a quick question. I have installed the 1090 graphing and this is the first 2hrs. Can one of you that’s better in the know explain what this graph it showing. Ie what is the signal like, is it poor, average. What sort of dbfs should I be aiming to achieve and is the noise excessive, acceptable ect.

Thank you


Can you tell us about your system. I believe you should shoot to have your weakest signal stronger than the noise. Looks like your noise is high but I’m not an expert, you may need a filter.

This is my last 2hrs

The noise reading is not reliable as its heavily influenced by overlapping messages.
So the noise will scale heavily with radar interrogation, number of ModeS / ModeC messages in the air.

The weakest signal is a better indicator.

As you can change the gain of the SDR and the system is unknown to us, commenting on the numbers is hard.
Post more graphs … range … message rate … aircraft count … it gives a compound picture.

Really the only way to find out if a particular part in the signal chain needs improvement is by improving it and comparing the results :slight_smile:
Well you can make educated guesses, but rather on the hardware in use than the graphs.

Hello, Here are all the graphs as of 2mins before posting this reply. I have been messing with the gain before I installed the graphs, but the best setting I have found is MAX gain, as any other setting dropped the number of aircraft & msgs received overall.

Uploading: 2.png…

That usually indicates that your gear isn’t the best.

With an LNA you usually need to reduce your gain (no matter if external or integrated).
If you have an LNA in there, then you have a terrible antenna or high coax losses.

Really the best thing to do is to check the actual reception vs the terrain in your location.
Get tar1090 and then do the panorama thing:
GitHub - wiedehopf/tar1090: Provides an improved webinterface for use with ADS-B decoders readsb / dump1090-fa

You have nice reception though, it’s not bad at all and many are just limited to much less by terrain.
It very much depends if you are into the min maxing / want to spend more on it or not :slight_smile:

Yeah no LNA installed, I have ordered a LNA, commercial antenna, 25ft of LMR200 cable to see what that does compared to what I’m running now.

So got the uputronics LNA delivered today and added it to the existing spider and pf100 cable and its made a very noticeable difference once I dropped the gain from max to 44.5 (was best setting I found) as I’m now picking up more aircraft in the 250+ distance, but only in 1 area and picking more up between 200/250.

I do have a 60cm antenna also. But to compare I need to somehow get it to same outdoor height and see how that performs against the spider when using the LNA and LMR200 cable on it.

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