Technician · correct answers only, in question-pool order.
A 50-watt mobile transceiver normally runs from a nominal 12-volt vehicle system and draws considerably more than 4 amperes while transmitting. A 13.8-volt supply rated for about 12 amperes is appropriate.
An SWR meter must be designed for the frequency range and RF power it will measure. A meter outside either rating may give poor readings or be damaged.
A transceiver can draw substantial current on transmit. Short, heavy-gauge DC leads have lower resistance, which reduces voltage drop between the battery or supply and the radio.
FT8 software generates and decodes audio-frequency tones. The radio's receive audio goes to the computer input, and computer-generated transmit audio goes to the transceiver input.
An RF power meter measures transmitter energy traveling toward the antenna, so it belongs in series with the feed line between the transmitter and antenna system.
A basic computer-radio digital interface carries received audio to the computer, transmit audio back to the radio, and a control signal that keys the transmitter.
The computer must receive the transceiver's decoded audio. One common connection is from the radio's speaker or audio output to the computer's line input.
At RF, inductance matters as much as DC resistance. Wide, flat copper strap has lower RF impedance than a long round wire or narrow braid and is preferred for bonding.
Battery ampere-hours describe stored charge capacity. Dividing ampere-hours by the equipment's average current draw gives an approximate operating time in hours.
A digital-mode hotspot acts as a local RF gateway. A nearby handheld or mobile radio talks to the hotspot, which then links that traffic into an internet-connected digital voice or data network.
A mobile transceiver's negative return should connect at the vehicle's battery chassis-ground point so the radio shares the intended low-resistance return path and vehicle grounding scheme.
An electronic keyer forms properly timed Morse code dits and dahs from manual paddle inputs, making consistent CW easier to send.
Too much microphone gain overdrives the SSB transmitter's audio stages. The result is compressed or clipped speech and a distorted transmitted signal.
Most transceivers let you enter frequency directly with a keypad or tune continuously with the VFO knob.
Squelch mutes receiver audio below a signal threshold. To hear a very weak FM signal, lower the threshold until the receiver audio remains open instead of being muted.
An FM receiver expects the signal to be centered in its passband. A small tuning error can make the recovered audio sound rough or distorted.
Scanning automatically steps through programmed channels or a frequency range and pauses or indicates where activity is detected.
Receiver Incremental Tuning, often labeled RIT or Clarifier, shifts the receive frequency slightly without changing the main transmit frequency. It is useful for making an SSB voice sound natural.
A DMR code plug is the radio's configuration database. It commonly contains repeater frequencies, color codes, contacts, channels, zones, and talkgroup information.
A receiver filter that is only as wide as the desired signal rejects more noise and nearby interference. Different modes therefore benefit from different filter bandwidths.
DMR routes voice using numeric talkgroup identifiers. Selecting or entering the desired group's ID tells the radio which group traffic to transmit to and receive.
An SSB voice signal typically occupies roughly 2.4 kHz. A 2400-Hz receive filter passes the speech while excluding more out-of-band noise than a much wider filter.
D-STAR transmissions include the operator's call sign as part of the digital system's routing and identification information, so the call sign must be programmed into the radio.