General exam: amateur radio practices
Station setup, test equipment, interference, speech processing and mobile/portable power. 60 questions, 10 at a time, starting with ones you haven't seen.
Rules to remember10 key amateur radio practices rulesShow the rules
- AFSK data signals must stay linear, and ALC action distorts them, so keep audio drive low enough that ALC stays inactive. (p. 39)
- Dual VFOs let you transmit on one frequency and listen on another, which is called split operation. (p. 39)
- An oscilloscope shows the shape of a signal over time, so it can measure complex waveforms a voltmeter cannot. (p. 40)
- A two-tone test reveals intermodulation products, showing how linear an SSB transmitter or amplifier is. (p. 41)
- Grounding metal enclosures ensures that dangerous voltages cannot appear on the chassis if a fault occurs. (p. 44)
- One S unit typically represents a 6 dB change in signal strength. (p. 45)
- One S unit is about 6 dB, and 6 dB is roughly a fourfold power increase, so the power must rise about 4 times. (p. 45)
- Auxiliary power sockets are wired for light loads and may not handle the current a 100-watt transceiver draws. (p. 46)
- A fully lit silicon photovoltaic cell produces about 0.5 volt with no load. (p. 47)
- Lithium iron phosphate batteries need controlled charging, so a solar panel must feed them through a charge controller. (p. 48)
Taken from the explanations to checked practice questions; page numbers link to the official handbook.
Sample amateur radio practices questions
1.Why do voltmeters have high input impedance?
- AIt improves the resolution of the readings
- BIt decreases the loading on circuits being measured
- CIt allows for higher voltages to be safely measured
- DIt improves the frequency response
Show the answer
✓ B. It decreases the loading on circuits being measured
A high input impedance draws very little current, so the voltmeter barely loads the circuit and reads accurately.
2.What is the purpose of the notch filter found on many HF transceivers?
- ATo restrict the transmitter voice bandwidth
- BTo remove interfering splatter generated by signals on adjacent frequencies
- CTo eliminate receiver interference from impulse noise sources
- DTo reduce interference from carriers in the receiver passband
Show the answer
✓ D. To reduce interference from carriers in the receiver passband
A notch filter cuts a narrow slice of the receiver passband to remove an interfering carrier or steady tone.
3.What is the effect of an incorrectly adjusted speech processor?
- AExcess intermodulation products
- BExcessive background noise
- CDistorted speech
- DAll these choices are correct
Show the answer
✓ D. All these choices are correct
An overdriven speech processor causes distorted speech, extra intermodulation products and excessive background noise.
4.Which of the following can be determined with a directional wattmeter?
- ARadio wave propagation
- BAntenna front-to-back ratio
- CStanding wave ratio
- DRF interference
Show the answer
✓ C. Standing wave ratio
A directional wattmeter measures forward and reflected power, from which you can work out SWR.