The KX3 is amazing QRP radio, probably the best in it’s class. One of the more remarkable features is it’s built in PSK/RTTY mode. Recently, the fact that when running 5-10 watts for prolonged transmit times causes the KX3 to heat up to a point where the temperature monitor will force you to scale back your power. While this is very annoying, it’s necessary in order to protect the KX3.
In the KX3 online discussions, a number of aftermarket heat sinks have been developed for the KX3. After reviewing the various designs, I took the plunge and placed a pre-order for the PAE-Kx31 from Pro Audio Engineering. More than just a chunk of aluminum on the back of the Kx3, this promised to have several features that I wanted:
- Fins for better passive heat transfer
- No sharp edges to snack in a backpack, clothing, or myself
- Anodized instead of powder coated
- The ability to continue to use my SideKX end plates and SideKX LEXAN cover
I got word last week that the item had shipped and it arrived Friday (April 18th). Excited as I was, I couldn’t perform the installation until Sunday. Here is the step by step with pictures along the way.
Removing the factory heat sink plate, you can see the original screws in the front row and the provided replacements behind them. Sadly, this means my brass ID plate from Arkay Engravers will have to find a new location.
With the original plate removed, the new heat sink is ready to go on. There are instructions for three different installations. I performed the first, which is a simple replacement of the original plate with the new heat sink. I did not use the thermal paste.
You can see these two screw holes next to the battery pack. When I removed the original screws, the nuts fell out of place and I had to fish them out. I attached these two screws first, and then attached the two on the end last.
All in all, I think this is a very fine product. Howard Hoyt (WA4PSC) paid a lot of attention to the details of this aftermarket heat sink and I think it was worth every penny!
Coming soon, I’ll do a key-down time vs temperature chart comparing operation with the new heat sink versus with the stock plate.