FlightAware Discussions

Please advise Pi4 2G

Hello all,

I would like to change my Pi 3B+ to a Pi4 2GB.

The “problem” is the cooling. The Pi will be in the same room as wehere we sleep, so a fan would not be a good option because of the noise. I cannot decrease the room temperature. Would be very nice in these warm days. :slightly_smiling_face:
I know there are good fans but none is 100% noise free. Some will say get used to it, but we are both very sensitive when it comes to noise.
I have been searching the internet, saw all kinds of solution, but would like to hear the experience/opinion of the forum members.
At the moment I am using an RTL-SDR dongle, but most probably will buy an Airspy Mini in the future. Guess that is why cooling could be an “issue”
All comments and ideas are highly appreciated.

Thanks

Look for a case with a large passive (no fan) heatsink.
I have a unit in my bedroom. It uses a Mode-S Beast so doesn’t require a lot of CPU. I just have heatsinks on the chips to try to keep them a little cooler. Use a quality heatsink compound, not the cheap crap that normally comes with heatsinks.
Sometimes orientating the case vertically can help with air flow and hence cooling.
I use quality 6"/15cm USB 3.x pigtails to allow for flexibility with the airspy and to give it some separation from the RPI. It may keep both of them a little cooler too.

Thank you so much for the fast reply. I forgot to mention that I also use a Uputronics filtered Preamp.
I don’t know if an Airspy Mini will takes a lot of the CPU.

May I ask you what heatsinks and compound you use?

The passive heatsinks will use a thermal pad and not paste.
Usually they have dimensions that won’t allow using paste.

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Check for “Armor Case”.

This is a specific case where almost the whole case is a heat sink.
It is available with or without fan and should be able to handle the combination.

I am running this combination without issues. I am using the one with fan and the temperature stays below 50°C

But i am using USB cables for the connection to the Airspy and to power the Uputronics using a seperate power cable. However you can also connect it to a free USB Port on the Raspberry.

This is an armor case:

And this the active one. You can operate the fan at 5V or 3.3V which slows it down, almost nothing to hear.
I also operated it indoor with the FA stick with no fan enabled

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Thank you for the advise. When I would opt for the one with fan, would it be possible to switch it off at e.g 9 pm and start at 8 am?
I do not know anything about programming.

While searching the internet I came across this site:https://magpi.raspberrypi.org/articles/group-test-best-raspberry-pi-4-thermal-cases-tested-and-ranked

I saw a Flirc case. Does anyone know if this one wouid be an option, as I seems it cools pretty well

Never thought about that. I assume it can be programmed, but i do not have the required skills for it.

The Airspy itself is not using much CPU, but some settings can bring one of the four cores to 80-90%. That means overall a CPU usage of around 20% which is not a problem at all

As long as you’re not doing anything else with that device, the heatsink case i suggested should be sufficient.

Currently i am running for testing purposes the Airspy with Filter on a Raspberry 3B
Even with only the small heatsink on the CPU, it’s getting 60°C only.

Setup with a Pi 3B and the temperature graph. Room temperature is 24°C, CPU load is 22%

image

I got the idea that an Airspy Mini would perform better with a Pi4, at least that is what I read here in the forum.

At the moment my CPU gets already 60C., I don’t have a heatsink

I think it depends what you want to do.

By pressing the last bits out of it, you would need to set the “-e” option to the higher number and you might use 20 MHz instead of 12.
I am not an Airspy expert, but this would not properly work on a 3B.
Mine is running on 12 MHz with “-e” set to 5

Yes, it will perform better since the USB-system is better designed on the Pi4 compared to the Pi3+ and because of the faster/better CPU. But you will have to do as @foxhunter points out: increase the “-e” value.

I’m running a side-by-side-comparison (with an antenna splitter) between a Pi4 2G (slightly over clocked and cooled with a fan-less armour case and a separate fan from a discarded PC PSU) and a cheap desktop PC made in 2014 running an AIrspy R2.

The PC is slightly better performing when running the same settings on both systems (about 1% better) and performs about 8-10% better when you set the same CPU-usage for airspy_adsb by increasing the “-e” on the PC until you reach the same usage as on the PC (for my setup with a sample rate of 20, that is -e 10.2 on the Pi4 and -e 13.4 on the PC, that gives a CPU usage of the airspy_adsb process of 80% on both systems).

Thank you for the extensive answers.
Guess I will start with the Pi4 with a “cooling case”. And purchase a Airspy mini later. Increasing - e and using 20 Mhz or 12 does not make sense right now. But hopefully in the near future it will :slightly_smiling_face:

Depending on the location and the environment the FA stick with the Uputronics LNA is delivering also very good results.

The RPi 4 does not get much warmer by using an Airspy.

Thank you for the help. Also the answers in ADS-B and GPS tracking made. my decision easier. Will go for the Armor case.
Now it is time to find a Pi4

The version with 2 GB is currently the best value for the money.
Make sure to get the original power supply as well.

Having an insufficient power supply can show different issues where you are not thinking about power on first hend.

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Thank you for the advise. I already read that in other forums as well. And I will go for the 2Gb as the 1Gb is discontinued. And I only use my Pi for feeding.

The 2G is hard to find due to the high demand.
Found two: Reichelt and Berrybase

I got two of my three at Rasppishop.de
Fast delivery and it’s in stock. Unfortunately shipping outside Germany is a bit more expensive

Changing the Airspy setting from -e 10 to -e 11 is getting more CPU load, but the temperature of the device does not seem to be interested on it.

This is very important to have in mind. The airspy needs a stable power source to work properly.

I’m using a MeanWell LRS-35-5 35W 5V 7A power supply to power my Pi4 setup. I’ve adjusted the input power so that I get 5.1V on the USB3 bus on the Pi4 (where I’ve connected the Airspy mini). I also power a bias-t injector and an 12V PC-PSU fan for cooling the entire setup.
This is not a pretty setup and a bit bulky, but it’s working really well.

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That’s it

i am using the original Raspberry power supply and the device is delivering power to the case fan, the Airspy and the Uputronics LNA.

No issue at all

Adjusting for the USB port voltage to be 5.1V , what’s your RPi4 input voltage?
Adjusting the USB port voltage under load to more than 5.0 V seems a bit excessive to me but it’s probably fine.