In this section, question G4B07 was eliminated and question G4B16 was renumbered G4B07, for a net loss of one question.
When you set up your amateur radio station, sometimes called your “shack,” you’ll not only want to acquire radios, but also some test equipment. The most basic piece of test equipment is the voltmeter.
Voltmeters may be either analog or digital, but most amateurs now choose digital meters because they are cheaper and more accurate than analog meters. An advantage of a digital voltmeter as compared to an analog voltmeter is that it has better precision for most uses. (G4B06) Another advantage is high input impedance. High input impedance is desirable for a voltmeter because it decreases the loading on circuits being measured. (G4B05)
The use of an analog meter might, however, be preferred over a digital meter in some applications. When adjusting tuned circuits, the use of an instrument with analog readout may be preferred over an instrument with a numerical digital readout. (G4B14) The reason for this is that with an analog meter you can more easily see how a circuit’s output changes as you tune it.
An oscilloscope is another handy piece of test equipment to have in your shack. With an oscilloscope, you can view signal waveforms. One advantage of an oscilloscope versus a digital voltmeter is that complex waveforms can be measured. (G4B02) An oscilloscope is an item of test equipment that contains horizontal and vertical channel amplifiers. (G4B01)
An oscilloscope is the best instrument to use when checking the keying waveform of a CW transmitter. (G4B03) The attenuated RF output of the transmitter is the signal source that is connected to the vertical input of an oscilloscope when checking the RF envelope pattern of a transmitted signal. (G4B04)
Antenna analyzers are instruments that can measure a number of different parameters associated with antennas, such as SWR. The antenna and feed line must be connected to an antenna analyzer when it is being used for SWR measurements. (G4B11) A use for an antenna analyzer, other than measuring the SWR of an antenna system, is determining the impedance of an unknown or unmarked coaxial cable. (G4B13)
Strong signals from nearby transmitters can affect the accuracy of measurements when making measurements on an antenna system with an antenna analyzer. (G4B12) This is because the antenna being analyzed will pick up RF energy from the nearby transmitters, and this energy will be read as excessive reflected power.
Standing wave ratio can also be determined with a directional wattmeter. (G4B10) To measure the SWR with a direction wattmeter, you first measure the power in one direction, then in the opposite direction, and finally calculate the SWR.
Another instrument often used for making antenna measurements is the field strength meter. The radiation pattern of an antenna can be determined with a field strength meter. (G4B09) A field-strength meter may also be used to monitor relative RF output when making antenna and transmitter adjustments. (G4B08)
One test that is often run on a SSB transmitter is the two-tone test. A two-tone test analyzes the linearity of a transmitter. (G4B15) Two non-harmonically related audio signals are used to conduct a two-tone test. (G4B07)