RadarBox FlightStick heat stroke?

i used two of the vents (they are low cost). they must be on a vertical surface or the IP rating is not correct. i mounted one down low on the front of the box and the other up high on the front

That’s really not too relevant. Especially because you can run the box much hotter with a fan while still keeping the RPi and dongles cooler.

True - it’s not 1W of actual heat, the energy is being used to turn the fan.

Any thoughts on EMI interference from the fan?

I wouldn’t be worried about that, i don’t see how a fan would produce GHz frequencies.

And compared with all the other stuff in the box, it’s unlikely to be a problem in my opinion.

Picked up a 50mm fan at lunch to experiment with.

That’s electrical energy consumed by the fan - after that, it is all converted to heat (first law of thermodynamics).

Similarly, a fan cannot cool below ambient.

Agree as @wiedehopf mentioned above, a fan would help drop the CPU temp closer to box/ambient temp. With my attic test around 40’C and my CPU around 80’C, I fan should keep it below the FA alert point of 70’C.

Adding a fan:

image

Dropped around 15 C.
(was already heatsinked)

It’s running an airspy at 20 MHz which permanently uses one core at 70 %.
The clock is set at 1.4 GHz permanently, no idle clock.
(It basically doesn’t go into idle anyway even if the function is on)

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Is underclocking an option to lower Raspi 3B CPU temps?

It doesn’t really help temperature much.

If you want to try:

Add

arm_freq=1000

to /boot/config.txt

This will still dynamically reduce clock speed if able.

(force_turbo=1 which i have enabled forces it to run at maximum set by arm_freq or default maximum if unset)

But as i said the benefits are most likely small.

Some more extensive changes:

arm_freq=900
arm_freq_min=250
core_freq_min=250
sdram_freq_min=250

over_voltage=-3
over_voltage_min=-8

Note the negative over_voltage numbers.
Running lower voltage might make the system unstable.
Pi 3 power consumption / undervolting - Raspberry Pi Forums

You can install bcmstat and use it to check the currently used values.

Worst case you need to remove the sd-card and change config.txt on the boot partition on your main computer.
(If it doesn’t start for some reason)

Using negative settings for voltage or lower frequencies than default won’t damage anything.
So there is no harm in experimenting.

The temperature went back up, and the ‘combo’ stopped working again. The reason I say ‘combo’ this time, instead of the FlightStick, is because I cannot access the Pi. I did not noticed or checked this previously.

I’m kind of puzzled now. What are the chances that 3 SD cards, 2 Pis, and 2 power supplies having the same problem, when the other ‘combo’ 4 feet away from it has been rock solid for over 500 days?

Can the FlightStick failure also bring down the comms (WiFi)?

Similar power supplies with similiar heat problem? :slight_smile:
Might both be reducing output to prevent heat death.

I replaced the FlightStick with the RTL-SDR Blog v3. Let’s see.

How much is the price difference?
There has been so much talk and praise about v3 that I am tempted to purchse it even though I have many surplus dongles.

The price is US$21.95 shipped.

https://www.rtl-sdr.com/rtl-sdr-blog-v-3-dongles-user-guide/

It stopped working again. I’m at a loss at what could be causing the problem.

I may try a fan on the Pi, but for now, removed everything, only one ‘station’ operational.

Try swapping the power supplies to confirm they are both good.

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I already did that, no change. I’m thinking that since they are both of the same type/brand, they failed the same way. I’ll look for another type/brand to see.

I’d try this.

You have a classic failure progression.
First the voltage starts to sag and the dongle drops out.
Then as the voltage sags more, the Pi fails.

Replaced the PSs with a third one. The temp is much lower today, so heat related issues are unlikely until the temp goes up again.

The ‘combo’ is performing better than before.

The main ‘combo’, and now this one, are using discarded PSs from other consumer electronics. The quality seems better. They are rated lower current wise, and yet are a little heavier.