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1. Don't use wire-wound resistors. They appear as resistors in parallel with a coil of wire, which equals inductance, which equals reactance, which equals a poor dummy load. Use carbon or composition resistors only. Even metal film resistors have significant inductance.
2. Don't use "engine oil". Use mineral oil or ask your electrical utility for some transformer oil. Most places will have nearly-empty 55-gallon drums of the stuff that they'll let you have for little or no cost.
3. Keep the leads straight and short. This works to keep the inductance as low as possible (see #1). You can't measure inductance with a regular multimeter.
4. As far as using "sand" instead of oil, I'd be very careful. Some "sand" is made of tiny ceramic beads, and this has some excellent thermal transfer properties. Regular desert or beach sand probably isn't as good.
2. Don't use "engine oil". Use mineral oil or ask your electrical utility for some transformer oil. Most places will have nearly-empty 55-gallon drums of the stuff that they'll let you have for little or no cost.
3. Keep the leads straight and short. This works to keep the inductance as low as possible (see #1). You can't measure inductance with a regular multimeter.
4. As far as using "sand" instead of oil, I'd be very careful. Some "sand" is made of tiny ceramic beads, and this has some excellent thermal transfer properties. Regular desert or beach sand probably isn't as good.
Mr
Salt Water Dummy Load
Simple easy to make and works great.
Old style design trusted and used to this day by alot of ham's
Just increase the size of the jar to increase the water capacity which in turn allows more wattage to be handled and cooled by the amount of water.
Salt Water Dummy Load
Simple easy to make and works great.
Old style design trusted and used to this day by alot of ham's
Just increase the size of the jar to increase the water capacity which in turn allows more wattage to be handled and cooled by the amount of water.
I'm not fond of the salt water idea to be honest. I prefer resistors in oil. this dummy load cost me the price of a 12 quart stock pot. I had the load itself scrounged from an old 500 watt transmitter. It's good for 1 Kw in open air and God knows how much in the silicone load oil it is immersed in.
