If you plan to transmit on your radio, you need a way to test your transmitter without radiating a signal. You do that by transmitting into a “dummy load”. I had a 20 Watt dummy load, but I needed one to handle 100 Watts, so I built a $40 kit in June. This was the first serious soldering I had done in years, maybe decades.
I built the Oak Hills Research RFL-100 kit. A pre-built 100 W dummy load is usually $150-200. This kit is $40.
The dummy load is twenty 5 W resistors in parallel. Here are the first two resistors, ready to be soldered.
And here we are, with half of the resistors soldered onto the board.
Here we see all the resistors soldered, the board installed in the nice enclosure, and soldered to the the input connector. I chose a BNC connector instead of the standard UHF connector. My ham shack is cabled with BNC. The enclosure is marked up under the connector mounting nuts because I ground off the paint with a Dremel tool. That was much easier than sanding the paint off.
Is it 50 Ω? Well, let’s see. Hmm 49.9 Ω is within 0.1%. My Ohmmeter is accurate to +/-0.5%, so I’ll take that as a solid 50 Ω.
Finally, let’s connect it to my new 100 Watt power amplifier on the ANT 2 port. Looks great, handling 100 Watts continuous with a 1:1 SWR.
If you have a transmitter and need a dummy load, I highly recommend building the Oak Hills Research RFL-100.