SDR Cooler

[FLIP]

Greetings all,

am after building some sort of cooler for my SDR, as its running almist 24/7 doing 1080 decoing (aircraft for those that dont know) and feeding to a well known website.

issue is it keeps getting very hot then stops receiving data, i have already taken it out of its original housing helps a little bit but not much.

i was thinking of using some sort of project box with a couple of fans to extract heat, but unsure what type of fans i should use.

should i use standard size ones like in a psu or those used on a gpu, or would the smaller ones ~4cm in length be ok?

will be powering with external wallwart not over usb.

the SDR in question is a Realtek RTL2832U+R820T from an Australian supplier up in NSW

would prefer to buy locally from somewhere like jaycar or element14 Australia, but am open to other suggestions

[Simon]

The short answer is how long is a piece of string? Thermal stuff is hard to decide. If your item is in an enclosed box just blowing some air through it will make a huge amount of difference you probably need to experiment.

[jeremy]

How hot are we talking? 60-70C can feel like it is burning (to some), but really that is not necessarily an issue. It would be a good idea to measure this.

In general, much more important than the geometric size of the fan is:

- having a good heatsink (you want to increase the surface area of the hot bits so that more air can have access to suck the heat away)
- having a good thermal bond between the heatsink and the hot object (thermal paste/pad/adhesive)
- having a defined airflow path which takes into account the geometry of the heatsink
- volumetric flow rate along the path (ie not fan "size", but fan flow rate and volume of air moved)

I don't think more than one fan would be necessary.

You can buy little black heatsinks for RAM chips on ebay for a few dollars, as well as some thermally conductive and adhesive pad material. I would probably start there. You can also steal a fan out of basically anything to start with (computer PSU, etc), they usually have their drive voltage printed on a sticker somewhere and it's simply a matter of connecting the red and black wire.

If you seem to need better cooling efficiency from the fan, you can try to make a wind tunnel out of some cardboard by folding it into rectangular prism-type tube, making the cross section as small as possible. This will force all of the airflow across the heatsink.

[FLIP]

sorry should have been a bit more in depth with the heating part, but thought stopping working was a good indicator.

i dont have a thermocouple or anything to measure the temp, but hot enough that you cant hold it for more than a few seconds.

i like the idea of the ram coolers, that might be a better option, have some dead ripjaws lying around so will rip them off that and give them a trey
(by old i mean they fail memtest)

the part that seems to be getting the hottest by touch anyway is the 28.800 mhz crystal clock oscillator

maybe im going about this all wrong, and these sdr`s are not designed to be run 24/7

will do further testing this weekend with the clipsal 500 and some dmr decoding with DSD+ and see how hot it gets, and if the same thing happens and it just stops working.

will report back sunday night ACDT, or monday.

[FLIP]

update:

seems fine doing decoding with DSD+ no real heating issues and no stopping working,  so it seems to be just doing 1090mhz adsb decoding thats causing the issues. so am going to do the testing with ram heatsinks for a week