Heatsink for RTL-SDR dongle

 Author:   Posted on:   Updated on:  2017-10-29T13:25:55Z
Some of the popular RTL2832U based DVB-T dongles that can be used as SDR tend to heat too much. As temperature increases, frequency drifts and sensitivity drops. Some dongles, especially those using R820T may stop working at all at high temperatures.

Marko Cebokli (S57UUU) used a thermal camera to measure the temperature of the dongle. He measured up to 85°C at the tuner chip (R820T). His images prove also that the dongle PCB doesn't do a good job at dissipating heat.

Although I'm using a R820T2 dongle (which is said to heat less than the predecessor R820T), I was surprised to see that after only 10-15 minutes the dongle was hot. Opening it up, I discovered that all ICs were hot (the tuner R820T2, the RTL2832U, the 1117 regulator, even the EEPROM was heated inside the closed case of the dongle).

Heatsink for RTL-SDR dongle
My first idea was to drop some solder on the thermal pads below the tuner and demodulator. Obviously, it couldn't do much (I couldn't keep my finger tip on the solder blob after 15 minutes of powering up the dongle). So I began making a heatsink. I needed two pieces of aluminium (or other thermal conductive material) that would "connect" the two ICs to a larger heatsink. I only intend to cool RTL2832U and R820T. I don't care about 1117 regulator (although this one heats too).

I made two of these that would fit on the ICs:

RTL-SDR heatsink adapter
RTL-SDR heatsink adapter
Then I fitted them on a larger heatsink after applying some thermal paste:

Heatsink for RTL-SDR dongle
Heatsink for RTL-SDR dongle
I placed the dongle PCB with the parts side down, then put a sponge on top of it before fitting the metal piece that hill hold it on place. The black piece of sponge is from a mouse pad☺.

RTL-SDR dongle on heatsink
RTL-SDR dongle on heatsink
As you can see in the top photo, the top metal piece has some holes for through-hole components, to avoid pushing them or making short-circuits. I didn't tighten the screws too much, just enough for the PCB to stay in place.

Even with this setup, after tuning to frequencies > 1000 MHz for a longer period of time, the heatsink reaches about 40°C, but that's still a big difference from 85°C. If your interested in other methods of cooling the dongle check out the RTL-SDR blog.

Whatever cooling method you want to use, keep in mind that temperature stability is better than very low temperature. How do you cool down your SDR dongle?

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