Ham Radio Technician Test Equipment & Tools Usage 2 — Questions and Answers
Question 1: What is the purpose of a dummy load when testing a transmitter?
- To boost output power during testing
- To absorb RF energy without radiating a signal (Correct answer)
- To match the antenna impedance to 300 ohms
- To filter harmonics from the output
Correct answer: To absorb RF energy without radiating a signal
A dummy load absorbs transmitter output power as heat so you can test the radio without broadcasting a signal over the air.
Question 2: Which instrument would you use to measure the standing wave ratio (SWR) of an antenna system?
- Oscilloscope
- Frequency counter
- SWR meter (reflectometer) (Correct answer)
- Signal generator
Correct answer: SWR meter (reflectometer)
An SWR meter (reflectometer) measures the ratio of forward to reflected power to indicate how well the antenna is matched to the feedline.
Question 3: What does a low SWR reading (close to 1:1) indicate about an antenna system?
- The antenna is radiating excessive harmonics
- The feedline has high loss
- The antenna and feedline are well matched (Correct answer)
- The transmitter output power is too high
Correct answer: The antenna and feedline are well matched
An SWR near 1:1 means almost no power is being reflected back toward the transmitter, indicating a good impedance match.
Question 4: A technician uses an antenna analyzer at the feed point of a dipole. What advantage does this have over measuring SWR at the radio?
- It shows the antenna's color code
- It eliminates feedline loss from the measurement, giving true antenna impedance (Correct answer)
- It measures transmitter output power directly
- It automatically tunes the antenna
Correct answer: It eliminates feedline loss from the measurement, giving true antenna impedance
Measuring at the feed point removes feedline loss from the reading, so you see the actual antenna impedance rather than a feedline-masked value.
Question 5: Which of the following is a common use for a signal generator in amateur radio equipment maintenance?
- Charging battery packs
- Injecting a known RF signal to align or troubleshoot receivers (Correct answer)
- Measuring antenna height
- Calculating feedline velocity factor
Correct answer: Injecting a known RF signal to align or troubleshoot receivers
A signal generator produces a calibrated RF signal that technicians inject into a receiver's input to test sensitivity, selectivity, and alignment.
Question 6: What safety precaution should you take before working on a capacitor in a transmitter power supply?
- Verify the antenna is connected
- Discharge the capacitor through a suitable bleeder resistor before touching it (Correct answer)
- Increase the supply voltage to clear stored charge
- Connect the capacitor directly to ground with bare hands
Correct answer: Discharge the capacitor through a suitable bleeder resistor before touching it
High-voltage filter capacitors can retain a lethal charge even after power is removed, so they must be safely discharged before any hands-on work.
Question 7: When soldering a coaxial cable connector, which technique helps ensure a reliable, low-resistance joint?
- Use cold solder to preserve the dielectric
- Apply flux, heat the connector and conductor together, then flow solder in (Correct answer)
- Drip solder onto a cold connector and press it on
- Avoid flux because it corrodes RF connectors
Correct answer: Apply flux, heat the connector and conductor together, then flow solder in
Proper technique requires heating both parts simultaneously so solder flows into the joint by capillary action, creating a solid electrical bond.
Ham Radio Technician Test Equipment & Tools Usage 2
What is the purpose of a dummy load when testing a transmitter?