Tuesday, December 30, 2014

New heat sink upgrade for the KX3

This was just recently announced via the KX3 User Group on Yahoo:

Hi all,

In response to feedback from KX3 users, we have improved the transceiver's heat sink, without significantly changing its outside dimensions. The new heat sink has twice the surface area and much greater mass, using an 'L' configuration that places part of the heat sink underneath the rig's chassis. A high-performance, die-cut thermal gasket is used between the rear panel and heat sink to ensure excellent heat transfer.

Our lab tests show that for a given power output level, the new heat sink provides up to twice as much transmit time as the original before power is automatically scaled back under firmware control.

(Larger, third-party heat sinks can still be used, if desired, to allow extended operation in data modes at full power, or at very high ambient temperatures.)

The new heat sink is already included in production KX3s, starting with S/N 7292 for kits, and S/N 7255 for factory assembled units. It can be easily added to existing KX3s using modification kit model #KX3HSKIT ($39.95). Refer to our Spare Parts and Mod Kits page, KX3 section:


If demand is high for modification kits, there may be a brief delay in filling orders.


Within hours, the complaining and whining has commenced. "Design flaw - I shouldn't have to pay!" seems to be the rallying cry.  And I disagree with that line of reasoning.  After all, the KX3 was designed to put out 12 Watts max. I use my KX3 at 5 Watts, for CW mostly, (OK, I'll confess - I made one SSB contact with it just to test that mode) so I don't have a need for a new and improved heat sink. However, who runs their radio at full output all the time anyway?  I may be naive, but even when I had QRO radios that were capable of 100 Watts out, I never ran them to full output. And the few times that I have used it, I don't think I've ever pushed my KXPA100 past the 90 Watt mark, even though it's capable of a lot more. When I do use it, I generally keep it around the 75 Watt neighborhood.

I suppose that if I was a digital aficionado, I would want the upgrade. And the $40 price tag that Elecraft is charging is way less than what third party after-market vendors are charging for their versions. I am assuming that a lot of guys are hoping that the "squeaky wheel" scenario will hold true.  I wouldn't hold my breath on that one - and all the complaining IMHO, only enforces the negative connotation about Hams being tighter than the bark on a tree.  It's pretty simple when you boil it down to the essentials, if you want to dance the QRO tune, you're just going to have to pay the piper.

72 de LarryW2LJ
QRP - When you care to send the very least!


  1. Good morning Larry, I agree with you and it's not because some may refer to me as "one who drank the cool-aid" it's because most other ham radio companies leave the rig improvements to the next addition of brand new radio that all op's have to pay full pop for. I have to admit that when I read Wayne's email about the new heat sink it came to mind "why are we paying for it" then it hit me being an Elecraft fan I have become spoiled with all the fantastic support we have been given. I am one of the op's who purchased the after market heat sinks and I did it for the digi operations. Elecraft has done so so much for product owners and it must get frustrating for them at times to hear some of the feed back they get…….but I must say both with Eric's and Wayne's emails I have never heard in at all. Good for them to be continuing to improve their products.
    I will get off my soap box now and wish you and your family Larry a very Happy New Year and thanks for the blog writing over this year and the years past. You have put great effort into it and I enjoy reading your posts.
    73 and all the best

  2. John N0EVH7:13 PM


    Maybe Elecraft did too good of a job on the rig design! The rig is designed for QRP field work, but performs so well everyone wants it as a primary or secondary rig in the shack.

    In the field you usually don't have enough battery on hand to run 12 watts full duty cycle modes!

    I have the ultimate heat sink design in the works. It bolts in place of the factor unit and has a trough that holds about 6 ounces of liquid. So if you are at the beach in the sun, you just put about 4 ice cubes in there and when they melt, dump them and load it up again!

    Happy New Year

    John N0EVH