# MLAT staying Red
**URL:** https://discussions.flightaware.com/t/mlat-staying-red/100677
**Category:** ADS-B Flight Tracking
**Created:** [August 26, 2026, 7:18am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677 "2026-08-26T07:18:09Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [August 26, 2026, 7:18am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/1 "2026-08-26T07:18:09Z")
Everything appears fine with my feeder and I feed multiple different services but I cannot get MLAT to go green on my FlightAware page: [davewill2010 ADS-B Feeder Statistics - FlightAware](https://uk.flightaware.com/adsb/stats/user/davewill2010)
Any idea on how I can get this fixed?
Thanks in advance
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [August 27, 2026, 9:38am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/2 "2026-08-27T09:38:54Z")
How accurate is your site location?
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [August 27, 2026, 10:11am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/3 "2026-08-27T10:11:17Z")
I believe it is spot on but if you can suggest how I can check and adjust I would be very interested to hear any suggestions.
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [August 27, 2026, 10:25am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/4 "2026-08-27T10:25:18Z")
Go to the paddle wheel and select “edit location”
Drag the map / pointer somewhere close to your actual location
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [August 27, 2026, 10:58am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/5 "2026-08-27T10:58:16Z")
OK I have dragged the pointer to the exact location of the antenna and will see if that helps.
Many Thanks for your help
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [August 27, 2026, 11:25am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/6 "2026-08-27T11:25:32Z")
I made the change about 25 minutes ago and it went green temporarily but then went back to red.
If I click on “View Anomaly” it shows this: S **ite 43072**
1. This feeder is not being used for multilateration because its timing information appears to be unreliable. This can be caused by the site location being incorrect, or because your Pi is running out of free CPU.
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### Author:  [@tomvdhorst](https://discussions.flightaware.com/u/tomvdhorst)
#### Post date: [August 27, 2026, 11:41am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/7 "2026-08-27T11:41:12Z")
What does the piaware log tell you ?
If you get the RTC Clock unstable message then the issue is that the timing is not accurate enough for piaware.
Since the Pi doesn’t have a RTC module this is not something you can easily fix as far as I know, I’ve experimented with RTC modules for a Pi but it never was capable to get rid of the incidental red MLAT box.
I take it for granted now since it usually pops up when there is very little traffic around in my setups.
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### Author:  [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)
#### Post date: [August 27, 2026, 1:51pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/8 "2026-08-27T13:51:33Z")
> [@tomvdhorst](#):
>
> If you get the RTC Clock unstable message then the issue is that the timing is not accurate enough for piaware.
The “Clock Unstable” message is basically never about the actual system time, it’s about the SDR oscillator.
I’m not even aware that there is a “RTC Clock unstable” message, i don’t think there is.
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### Author:  [@tomvdhorst](https://discussions.flightaware.com/u/tomvdhorst)
#### Post date: [August 27, 2026, 1:58pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/9 "2026-08-27T13:58:26Z")
I’m referring to
[2026-08-27 15:53 CEST] mlat-client(2458694): Server status: clock unstable
There’s no mention of the RTC clock indeed but that has always been my assumption since the server sees the clock as unstable but that could be the SDR as well indeed.
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### Author:  [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)
#### Post date: [August 27, 2026, 2:06pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/10 "2026-08-27T14:06:19Z")
> [@tomvdhorst](#):
>
> There’s no mention of the RTC clock indeed but that has always been my assumption since the server sees the clock as unstable but that could be the SDR as well indeed.
Not sure i’ve corrected you specificially on this exact error but it sure feels like it 🙂
Pointing at the system time for that error is … a red herring.
It can be a wrong position or data getting lost between SDR and decoder (on USB).
The reason for data getting lost can be multiple things, bad SDR or not enough voltage making it to the SDR (extension / power supply / pi board)
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### Author:  [@tomvdhorst](https://discussions.flightaware.com/u/tomvdhorst)
#### Post date: [August 27, 2026, 3:28pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/11 "2026-08-27T15:28:41Z")
Actually you’re pointing out that the logic I’m using isn’t as straightforward as I was thinking. So no offense taken in your reply, I’m still learning everyday from others on these boards.
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [August 31, 2026, 10:53am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/12 "2026-08-31T10:53:27Z")
The strange thing Tom is that its so intermittent. Sometimes its green for quite a while then all of a sudden it goes red for a considerable amount of time and then back to green (wash, rinse, repeat) without intervention.
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [September 6, 2026, 11:30am UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/13 "2026-09-06T11:30:34Z")
MLAT continues to be a problem for me despite buying a new ProStick Plus and adjusting my location to as close to exact as possible. Sometimes MLAT stays green for a while but then goes red. It IS intermittent but its red more than its green.
Is this fixable or do I just need to live with it ?
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [September 6, 2026, 2:52pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/14 "2026-09-06T14:52:36Z")
On reading some other posts regarding MLAT not working I saw it mentioned that it can be caused by there not being being enough close by receivers but on checking mine I find there are lots!
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### Author:  [@Socrammmfreitas](https://discussions.flightaware.com/u/Socrammmfreitas)
#### Post date: [September 6, 2026, 3:52pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/15 "2026-09-06T15:52:12Z")
If an intermittent problem seems difficult to resolve:
Could you post your Feeder log so other users can check for anomalies? Just go to your page and click on the gear circled in red on the right side of the image.
Check if the location accuracy is set to “precise/exactly.”
Enter the location with a precision of 5 decimal places.
And the installation height as well.
Finally, post the log when this anomaly is occurring so other users can see it…
I can’t tell you whether the problem is hardware-related or due to a configuration conflict between the various sites you manage. However, there are many users here who also manage multiple services, and they might be able to give you a valuable tip.
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### Author:  [@Socrammmfreitas](https://discussions.flightaware.com/u/Socrammmfreitas)
#### Post date: [September 6, 2026, 4:04pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/16 "2026-09-06T16:04:36Z")
Some problems with MLAT generally caused by hardware:
Saturation of one of the RPi CPU cores (over 100% usage). Since you are feeding data to multiple sites, CPU usage spikes at times, causing delays and message loss, which makes MLAT unstable.
Long USB cable causing voltage drop
Using an SDR in an unventilated area or one subject to rapid temperature fluctuations (this primarily affects generic dongles that do not use a TCXO).
Low air traffic region: In areas where, at certain times, there are no aircraft flying—or none being detected by at least four stations simultaneously—MLAT loses synchronization. (MLAT relies on the aircraft’s GPS for time-stamping; without an aircraft present, synchronization cannot be maintained and is lost, only resuming once an aircraft passes by and its signal is picked up by multiple stations.)
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### Author:  [@geckoVN](https://discussions.flightaware.com/u/geckoVN)
#### Post date: [September 6, 2026, 4:05pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/17 "2026-09-06T16:05:36Z")
> [@Socrammmfreitas](#):
>
> Check if the location accuracy is set to “precise/exactly.”
That doesn’t affect the calculations, it’s just a privacy option to hide your exact location to other viewers.
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### Author:  [@Socrammmfreitas](https://discussions.flightaware.com/u/Socrammmfreitas)
#### Post date: [September 6, 2026, 4:09pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/18 "2026-09-06T16:09:11Z")
Thanks for the correction.
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### Author:  [@wiedehopf](https://discussions.flightaware.com/u/wiedehopf)
#### Post date: [September 6, 2026, 4:31pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/19 "2026-09-06T16:31:30Z")
> [@davewill2010](#):
>
> Is this fixable or do I just need to live with it ?
It is somewhat a problem with pi3s.
And their load.
And their power supplies.
And just depending on luck.
You can have better luck if you don’t run adsb.im in this very specific case.
It’s a combination of load and the pi3 just being very bad USB hardware.
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### Author:  [@davewill2010](https://discussions.flightaware.com/u/davewill2010)
#### Post date: [September 20, 2026, 1:17pm UTC](https://discussions.flightaware.com/t/mlat-staying-red/100677/20 "2026-09-20T13:17:44Z")
After much swapping of hardware recently my MLAT is now vastly more stable then before and it seems the key is the power supply providing power to the Pi. I had swapped it several times for what I thought were know good power supplies but to no avail so bought a brand new one from PiHut and now is rare for for MLAT to go red unless there is very little traffic in the air.