What is a dummy load resistor?
A dummy load is a resistor used to load any radio frequency generator/amplifier to simulate an antenna for testing purposes. It’s used to allow full power output while testing or experimenting without radiating a radio frequency signal.
Can you use a resistor as a dummy load?
Unfortunately, wirewound resistors are not ideal as dummy loads because values <100 Ω have significant inductance compared to their resistance. Fortunately, 50 W non-inductive thick-film resistors are available, and multiples of these can be fastened to a large heatsink to make a non-inductive dummy load.
What is a dummy load RF?
In RF, dummy loads are used to simulate a load of an antenna on a system without producing radio waves. They also use these for tuning the RF device before putting it online. They simulate a perfectly tuned antenna that is connected to the amplifier.
What is RF resistor?
RF resistors are excellent for mounting directly to heat sinks for improved heat dissipation. The devices are available in single, double and four hole flange-mounting styles. These devices have standard resistance values of 50 & 100 ohms. The RF resistors are offered in power ratings ranging from 250 to 800 watts.
What color is a 50 ohm resistor?
Red
Resistor Band Colors
| Color | Value |
|---|---|
| Red | 50 ppm/ºC |
| Orange | 15 ppm/ºC |
| Yellow | 25 ppm/ºC |
| Green | N/A |
What does a dummy load consist of?
So a dummy load usually consists of a composite resistor, one with a resistive material, but no coils (so no inductance), or non-inductive. It usually contains a heat sink, or some way to dissipate the heat, so the resistors don’t burn up.
How do you test a dummy load?
1 Answer
- The simplest test on a dummy load you can perform is to measure it with an ohmmeter — it should be 50 Ω (or whatever the specified impedance is).
- The above test tells us that it is 50 Ω at DC, or 0 Hz.
- A dummy load should have the expected impedance, but so does an antenna.