Dongle (FlightAware) overheating and failing...

[Basil B]

This is the third time this has happened...
The first one was one of the cheapos...
Then I got a FlightAware (orange) stick...
Then a few months back I got a FlightAware (Blue) stick...
Noticed today that the system was not picking up flights again, on investigation I found USB plug to be very hot. I already have a fan to circulate the air as the unit is housed in an old biscuit tin located in the loft, voltage into the RPI 3B+ is 4.96v, is there any remedy for this issue?
20200818_093949.jpg

[Burton_Ped]

Is there a particular reason why you have it in a tin? The attic space of houses can get very hot even on a cloudy day so it may get like a sauna inside the tin even with a fan. I have mine just mounted to the inside of the gable end wall and it's been fine. The Pi reports a core temp of 49.2C.

[ScrappyLaptop]

I used a radio dongle with an aluminum case because it seemed like a good idea. But when I noticed the heat it gave off while still on my workbench I temporarily clamped it to an old copper 1U server heat sink. Max tracking distance doubled. So for the final design I sandwiched it between two aluminum heat sinks with thermal tape at the interface. The Pi case is also a heat sink, but it is kept mostly isolated from the frame that acts as a heat sink for the radio.

But also...if you have a tight lid on that tin, how does the hot air escape? It needs ventilation or those fans are just circulating hotter and hotter air (some heat will transfer to the tin & radiate from there, but not much).

I'm guessing you'd be better off using the tin as a heat sink directly. That would mean taking the plastic case off the radio dongle & using something like (electrically insulating) thermal tape between it and the tin, securely & tightly held in place with some pressure (ie something mechanically & electrically sound that presses the PCB against the tape & tin).

[Basil B]

Is there a particular reason why you have it in a tin? The attic space of houses can get very hot even on a cloudy day so it may get like a sauna inside the tin even with a fan. I have mine just mounted to the inside of the gable end wall and it's been fine. The Pi reports a core temp of 49.2C.

It has to be a very sunny day for my loft space to get warm and even then it does not get much above 30C, and we have not had many sunny days in the last few weeks...

Obviously, when I retrieved the unit from the loft space I noted the enclosure was not warmer than the local ambient temperature (less than 20C) and on opening, I think I would have noticed had the temperature of the escaping air been warm.

The reason for the tin is two-fold...
1. RF screening I have two cellphone masts within 150m of my home.
2. To keep it clean, my loft space is like the black hole of Calcutta.

At present, I have the unit on the workbench, I have removed the dongles board from its plastic housing, affixed 3 8mm heat sinks to the voltage regulator and two main chips, it has been on soak test for nearly 72 hours without any problems.

I am now designing a housing to hold the bare board and a fan.
20200913_103609.jpg

[F-EGLF1]

This is the third time this has happened...
The first one was one of the cheapos...
Then I got a FlightAware (orange) stick...
Then a few months back I got a FlightAware (Blue) stick...
Noticed today that the system was not picking up flights again, on investigation I found USB plug to be very hot. I already have a fan to circulate the air as the unit is housed in an old biscuit tin located in the loft, voltage into the RPI 3B+ is 4.96v, is there any remedy for this issue?
20200818_093949.jpg

Slightly off topic, nice looking cavity filter, do you mind if I ask where you got it? And are they available at a sensible price?

[Basil B]

Slightly off topic, nice looking cavity filter, do you mind if I ask where you got it? And are they available at a sensible price?

http://shop.sysmocom.de/products/cf1090-kt30