Even though this particular fan I’m using is rated for being powered with 12VDC, anything up to at least 15VDC is just fine, as I will explain briefly. And this voltage range means it’s perfect for portable amateur radio ops and around the shack, where you will encounter a variety of voltages based on batteries or power supplies.
I use this fan to cool my Elecraft KX3 with a 3rd party heatsink when using digital modes like FT8 with higher duty cycles than CW or voice. Just point the fan at the heatsink, and done. My heatsink is a Cooler KX heatsink from VE7MN, but those don’t appear to be available anymore, and it doesn’t matter which one. You’re not mounting this on the heatsink. You’re just having the fan blow onto it to help it move more air over the heat sink. The whole setup is small and flexible enough that I find many uses for it, and it makes virtually no noise when used in the configuration below.
Most fans available tend to be 25mm deep (about one banana unit), and I’m using an 80mm fan (80x80x25mm) rather than the more common 120mm or 140mm variety. Why? Those fans are too big and likelier to tip over when set on their sides. Of course, we could fashion some legs to hold it up, but we can do without that for a minimalist setup.
Bonus: If you’re using one of the excellent NoGaStands for your Elecraft KX3, an 80mm fan will fit nicely under the shelf for the Elecraft PX3 panadapter! Ok, you can also dry the sweat off your forehead or fist on a hot day.
As shown in the picture above, a Noctua NF-A8 ULN comes with several helpful accessories, including ones to tune speed and the already little noise it makes. And we will use all of them here.
- NA-AC1 – 4/3 pin adapter
- NA-RC12 – low noise adapter
- NA-EC2 – extension cable
The NA-RC12 does the magic for not overvolting the fan with higher than 12VDC since it drops the power allowed to the fan to reduce the rotation speed to reduce the noise.
You will also need a pair of Anderson PowerPoles to put on the end of the NA-AC1 cable. Chop off the four-pin connector; the fan only has three pins anyway. And we only care about the red and black wires. This will become our adapter to the PowerPole supply (you have everything PowerPoled, right?). You can push the protective sleeve back so that when you crimp the contacts onto the wires and insert them into the housing, there is no gap for a tidy finish.
Next, you will need a pair of 80x80mm fan grills. I found this fan grill 2-pack from CoolerGuys convenient. Leave the brown rubber vibration isolators on and mount the fan grill on top of them; these bumpers help the fan stand and not slide around. When it’s all done, you should end up with something that looks like this:
If you’ve come here, maybe you found this helpful. Leave a comment below!