Now that I’ve moved up to 100 watts with my K3, I need at least a 100 watt dummy load for tuning and testing purposes. I used to have a Heath Cantenna but turned it in to the hazardous substances disposal service. My Dad had bequeathed it to me and I knew it had some sort of pcb based transformer oil in it that would ooze out from time to time. Plus, I don’t expect to be running a kilowatt any time soon.

I had built an Elecraft DL-1 20 watt dummy load with the plexiglass enclosure by W8FGU. It worked great for my QRP days, along with the NorCal Power Meter. Now it is time to step up to 100 watts all the way around (stay tuned for my entry on the Elecraft W1 Wattmeter).

In looking over the possibilities I decided on the Oak Hills Research (OHR) 100 watt dummy load that Morse Express sells. It’s really a circuit board, a bunch of resistors, a connector, and a very nice cabinet. Here’s the photos of the kit coming together.

 

Final Product
Final Product
Mounted in the Cabinet
Mounted in the Cabinet
Completed Circuit Board
Completed Circuit Board
Kit Inventory
Kit Inventory

The kit went together very well. As noted above, the quality of the cabinet is first class — excellent metal work and superb paint job. Not sure what I was expecting but this exceeded my expectations. The load measure 49.6 ohms with my Triplett ohmmeter. Which is well within the tolerances expected with this type of arrangement.

I used it later that day to test my Elecraft W1 wattmeter that I also put together this weekend. I used both of them to adjust my K3’s internal wattmeter and transmitter gain. I will review the W1 later, after the enclosure arrives and after I test the software.

Thanks for stopping by. Let me know what you think.

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Jim-K5ND

Freelance writer and active Scouting volunteer. Retired publishing and communication executive who writes for fun and to finance his hobby, amateur radio.

4 COMMENTS

  1. I also built one of these. Well, actually two–one for myself and another for a good ham friend of mine. Jim is absolutely right–the quality of the board, components and enclosure is awesome, and anybody who works HF needs a dummy load. This is an excellent first time kit for somebody new to radio-electronics: The 42 solder connections will be great practice, and the resistors are large enough for even older people like me to see!

    -Woody K3VSA

    • Thanks for your comments, Woody. Very nice quality cabinet, too. It’s held up well. Just had it out the other day to recalibrate the K3’s internal wattmeter. Very handy to have around the ham shack.

      73, Jim, K5ND

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