Sudden drop in message rates

Have some others the same weird thing?

I’d guess component failure or heavy interference.

Someone near 52.5, 6.0 (ignore the message rate it’s not the original rate at the receiver):

Thank you for the reply. but my airplanes seen dropped as well.

Hi All,

yesterday it happenend again, around 17:)) my message rates and the amount of airplanes seen dropped tremendously. Could someone please explain this. I @wiedehopf explained it could be interference, but two days in a row? And if so what could cause this and how could I “solve” it

if you have a RTL-SDR dongle you can use that as a spectrum analyser.
When the singal drops you can start the analysis and you can determine is there is something interfering with your set-up.

Dou you use a filter to block out other signals ?

Post more graphs … as in range / signal especially.

If it’s in your own house … you’d probably know what runs during that time frame.

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Thank yo for the reply.
Nothing has changed at home. that is why I am so confused. Here are the other graphs, hope they will sense to you.

`Thank you for the reply.

I am using an uptronics ->airspy-> pi with a Jetvision antenna. As mentioned before nothing changed at home.

You have by chance the FA filter? You could put it in front of the uputronics and possibly alleviate the issue (if it’s strong signals that are not on 1090 MHz, if its broadband noise then there is nothing you can do).

Also the airspy graphs would be interesting.

Soory don’t have a FA filter and I forgot the Airspy. Graphs.Please forgive me.

I’m going to bug out then, I don’t have sufficient knowledge on these components to be able to help you

All the same :wink:

No worries haha!

Yeah it’s very likely the uputronics LNA is getting overloaded.
It won’t hurt it but the reception will be bad when the interference is on.
Could also be broad band interference, pretty hard to tell.

Maybe you have an rtl-sdr lying around you can connect to a laptop and connect some sort of antenna.
Then you can go and try and localize the emission, maybe even find the frequency.
You should go around without it as well to get a feel for the baseline.
Not sure which programs for spectrum are available …

SDR# would certainly work i think.

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I don’t have an airspy, uptronics or jetvision in my inventory ( most of the other stuff is present) :smiley:
Interference is hard to catch when it pops up outside of your own house ( it looks like interference as far as I can judge)

@wiedehopf and @tomvdhorst

Thank you both for the replies and suggestions.

For what I understand the drop in reception might be caused by interference. Interference is difficult to locate and even more difficult to eliminate.
As nothing has changed inside my home, it is plausible that it is form “the outside world”.
Hope this is correct?

I have no clue what could cause it at 17:00 hrs. Haven been thinking of all kinds of things but nothing has come up yet. :thinking:
As I have a Macbook, it is also very difficult to find a spectrum analyser, and even if so, I would need the assistance of you guys to understand.

I still things it is weird as my reception is/was rather steady the last months/, especially taking in consideration my terrain limitations.
Messages rates drops from 17:00 - 04:30

If there’s nothing changed in you house then the interference should be from outside your house., that is correct.
For a spectrum analyser running on a mac you can use an RTL-SDR dongle combined with the software in the link

The thing is that you might be able to verify that there is interference coming from outside your house but that doesn’t mean you can pinpoint the location. All the spectrum analyser does is showing if there are strong signals present in the spectrum where the airspy is operating.

Is this a daily occurence ? So every day at the same time ? That would indicate it is a time based device that is operating then. Is something swithed on at 17:00 ? Timebased poweroutlet maybe ?
No changes in your immediate surrounding ? A neighbour has started with broadcasting or a radio amateur that started the last week ?
A walk in the neighbourhood might reveal some antenna’s you were not aware of previously.

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Really it’s gonna be something overpowering the uputronics LNA.

So i’d probably look from 90 MHz to 2 GHz … for anything that’s super strong.

If it’s just broadband noise, it’ll just be a raised noise floor which is visible as well just not quite as easy.

I mean if you walk around the streets around you, you can probably get the location where the signal is the strongest as in narrow it down to a house if it one of them.
If it’s a mast high up / further away, this will be harder.

It’s not precise times and they vary (just look at the graphs posted).
I’d say someone switches on the lights at 1700 or starts watching TV then switches it off between 1 to 4 AM.


I agree on that indeed, it will be something broadband or something that is overpowering the LNA.

no problems yesterday and today judging by your statistics ?

No no, it’s either broadband or overpowering the LNA :slight_smile:
Not at the same time.

ok I understand it now :wink: :+1: