Ham Radio Exam Questions- General
Practice Questions
Q: How are the two separate frequencies of a Frequency Shift Keyed (FSK) signal identified?
- A: Mark and Space
Q: Which of the following is an advantage of an NVIS antenna?
- A: High vertical angle radiation for working stations within a radius of a few hundred kilometers
background
FSK
FSK is commonly used for caller ID and remote metering applications. FSK is also known as frequency modulation (FM). You will often hear the terms FSK and AFSK when talking about RTTY on the HF bands. FSK means Frequency Shift Keying and AFSK means Audio Frequency Shift Keying. MARK is always the higher RF frequency and SPACE is always the lower RF frequency.
NVIS
An NVIS antenna (Near vertical incidence skywave) is a horizontally polarized radiating element that is from 1/20th wavelength (λ) to 1/4 wavelength above the ground.
ALC on SSB
Automatic Level (Linearity) Control. This is used to reduce distortion by control of the signal strength going into the power amplifier in the transceiver. Amplifier drive is controlled by the ALC by use of an adjustable negative-going DC voltage which is fed back to the transceiver. You adjust the ALC to match your own speech, which is to say how loud you talk into the microphone, your distance from the mic, etc, to arrive at the most efficient way to deliver power without distortion.
PEP
Peak envelope power (PEP) is the highest envelope power supplied to the antenna. This max power is at the peek of the waveform, something not detectable with a typical power meter. PEP is best determined using an oscilloscope.
