Cheap Dummy Load

[kc4umo]

I was in the shop this past week end and decided I needed another dummy load for one of the test benches. Figured I did not need a lot of power. Just something to test with.

After searching my inventory I found a bunch of 680 ohm 5 watt carbon film resistors. 680/14 = 48.5 ohms. Went to Lowes and picked up a 1 quart paint can. I cut two 1 ¼ x 4 inch circuit boards. Taped them together and drilled a series of holes to accept the resistor leads.

I mounted a SO-239 in the lid and also a 1/8th brass tube in a “J” shape. This was soldered in place and a small amount of candle wax applied to the hole. I then attached the circuit board to the SO-239.

After filling with mineral oil the load shows 50.6 ohms.
With the rating of the resistors in oil it should handle about 700 watts at short intervals.
Fairly simple project and cheap.

[N4VGB]

Punch another hole in the lid and add a BNC connector with a short length of straight copper wire soldered to the center pin on the BNC. Then you'll have a pickup point for a spectrum analyzer, scope, audio monitor, etc.

[kc4umo]

Punch another hole in the lid and add a BNC connector with a short length of straight copper wire soldered to the center pin on the BNC. Then you'll have a pickup point for a spectrum analyzer, scope, audio monitor, etc.

Now that is a great idea!
My Cantenns has that but they used an old phono plug on it. I am going to do that.

Thanks