CRAC Bilingual Manual: Transceiver Front-Panel Controls | 收发信机面板控制 (24 questions)

The Chinese name of RIT on the amateur transceiver panel and its meaning are:

1. AReceive Incremental Tuning — fine-tuning the receive frequency while keeping the main receive tuning unchanged.
2. BTransmit Incremental Tuning — fine-tuning the transmit frequency while keeping the main transmit tuning unchanged.
3. Csplit operation — receiving and transmitting on independent frequencies.
4. Dclear all data in the channel-frequency memory.

The Chinese name of XIT on the amateur transceiver panel and its meaning are:

1. ATransmit Incremental Tuning — fine-tuning the transmit frequency while keeping the main transmit tuning unchanged.
2. BReceive Incremental Tuning — fine-tuning the receive frequency while keeping the main receive tuning unchanged.
3. Csplit operation — receiving and transmitting on independent frequencies.
4. Dclear all data in the channel-frequency memory.

The Chinese name of SPLIT on the amateur transceiver panel and its meaning are:

1. Asplit operation — receiving and transmitting on independent frequencies.
2. BTransmit Incremental Tuning — fine-tuning the transmit frequency while keeping the main transmit tuning unchanged.
3. CReceive Incremental Tuning — fine-tuning the receive frequency while keeping the main receive tuning unchanged.
4. Dclear all data in the channel-frequency memory.

For what scenarios is the split (SPLIT) operation mode of an amateur station mainly used? (Choose all that apply.)

1. AA large number of stations continuously answer your call simultaneously, causing a severe pile-up. You can then ask each station to answer on a frequency about 2–5 kHz above your main carrier, so that no station can clearly hear your signal.
2. BThe two sides are in different ITU regions, with some difference in band or mode, but need to communicate with each other.
3. CTwo amateur stations do not want other amateur stations to hear the full content of the conversation.
4. DA certain amateur station uses separate receive and transmit equipment and genuinely cannot make them work on the same frequency.

Which function can make an SSB or CW signal that sounds high or low in pitch become normal?

1. ARIT
2. BIF bandwidth selection
3. Csquelch (SQL) threshold
4. DAGC release speed

Some transceivers have a CW-R function that reverses the sideband used when receiving CW. This function is beneficial for:

1. Areducing or eliminating interference from other signals.
2. Bgenerating the opposite sideband of the CW signal to significantly cancel noise interference.
3. Cdoubling the signal capacity within the same receive bandwidth.
4. Dpreventing accidental keying and unintended transmission.

Some transceivers have a QSK function, i.e. “full break-in”. The specific meaning is:

1. Athe receiver can receive signals during the gaps between the transmitted code elements.
2. Bthe operator must manually switch the transmit/receive switch at the end of each transmission.
3. Cactivating this function can increase the sending speed of the automatic keyer.
4. Dactivating this function can increase the transmitter’s output power.

What is the advantage of a receiver with multiple bandwidth selections?

1. AIt can select a suitable receive bandwidth for the operating mode in use, improving the received signal-to-noise ratio.
2. BIt can allocate different bandwidth intervals to multiple parallel receivers running simultaneously.
3. CIt can simultaneously receive signals of different modulation types within the same bandwidth.
4. DIt can assign a separate receiver to each bandwidth and monitor different signals simultaneously.

An amateur receiver’s IF filter bandwidth offers choices of 100 Hz, 400 Hz, 2.7 kHz and 6 kHz. If choosing appropriate settings for CW, SSB, AM and FT8 signals, they should be in order: (Choose all that apply.)

1. ACW uses 100 Hz or 400 Hz
2. BSSB uses 2.7 kHz
3. CAM uses 6 kHz
4. DFT8 uses 400 Hz

We always want the receiver’s receive bandwidth to match the necessary bandwidth of the current operating mode. This is because:

1. Ait yields the best received signal-to-noise ratio.
2. Bit gives the best receiver input impedance.
3. Cit maximizes the receiver’s dynamic range.
4. Dit lets you see more signal activity across the band, which helps catch more DX contacts.

When participating in VHF amateur radio contests or EME communication experiments, we may need to add an external RF preamplifier for the receiver. Where in the whole transceiver system should this device normally be installed?

1. Abetween the antenna and the receiver.
2. Bafter the transmitter power amplifier.
3. Cbetween the transmitter and the antenna tuner.
4. Dat the receiver’s audio output.

Where in the amateur radio equipment should an external low-pass filter used to enhance rejection of spurious emissions be installed?

1. Abetween the transmitter and the antenna.
2. Bbetween the transmitter and the receiver.
3. Cbetween the transmitter and the power supply.
4. Dbetween the transmitter and the microphone.

When conducting multi-operator multi-station HF contests, to prevent as much as possible the transmitter’s harmonic interference with receivers operating on doubled-frequency bands, we can series-connect an LC low-pass or band-pass filter matched to the operating band between the transmitter and antenna. Regarding such a filter, which statement is correct?

1. AThe higher the filter order, the better the suppression of doubled-frequency interference.
2. BThe lower the filter order, the better the suppression of doubled-frequency interference.
3. CThe higher the filter order, the smaller the power loss.
4. DThe higher the filter order, the greater the power it can withstand.

A stub filter, sometimes called a branch-line filter (coax stub), is a band-pass or band-reject filter made from feed line, occasionally seen in amateur radio contest setups. Which of the following descriptions of this filter are correct? (Choose all that apply.)

1. AA 40 m-band quarter-wavelength (electrical length) coaxial cable shorted at the far end: passes 40 m and 15 m signals, shorts the 20 m and 10 m band harmonics.
2. BA 40 m-band quarter-wavelength (electrical length) coaxial cable open at the far end: passes 20 m and 10 m signals, shorts the 40 m and 10 m band harmonics.
3. CA 40 m-band half-wavelength (electrical length) coaxial cable shorted at the far end: passes 40 m and 15 m signals, shorts the 20 m and 10 m band harmonics.
4. DA 40 m-band half-wavelength (electrical length) coaxial cable open at the far end: passes 20 m and 10 m signals, shorts the 40 m and 10 m band harmonics.

Some transceivers have an RX ANT connector. This connector is used to:

1. Aconnect a separate receive antenna.
2. Bconnect an external separate receiver.
3. Cconnect to the transmit antenna via a 3 dB coupler.
4. Dconnect to the transmit antenna via a preamplifier.

Some transceivers have a built-in auxiliary receiver, mainly used for: (Choose all that apply.)

1. Ausing a separate receive antenna to tune independently to any frequency, enabling split operation.
2. Busing a separate receive antenna working on the same frequency as the main receiver, enabling diversity reception.
3. Coutputting I/Q baseband signals to the headphone jack to achieve independent RTTY decoding.
4. Doutputting IF signals to an IF jack to connect an independent band spectrum display.

Diversity reception uses multiple receivers to simultaneously capture the same signal, to obtain more complete information and make the signal easier to discern. But when erecting a separate receive antenna for diversity reception for the auxiliary receiver, note that: (Choose all that apply.)

1. AThis antenna should be placed farther from the main antenna; e.g., at least one working wavelength away.
2. BThe polarization of this antenna should preferably be orthogonal to the main antenna; e.g., use horizontal and vertical antennas respectively.
3. CTo capture more information, we should install a preamplifier on this antenna.
4. DIf the antenna is broadband, we must install an external band preselector for it.

When participating in contests or DX contacts, we may need a standalone SDR receiver to assist CW or FT8 decoding software, to obtain more coefficients and improve contact results. If such a receiver is a portable product with a USB interface, we need to prepare:

1. Aa PC, SDR receiver software, CW or FT8 decoding software, and bridging software that splits the audio data stream.
2. Ba development environment such as C/C++, Python, or Rust, ready for writing SDR software.
3. Cscientific computing / large-data-processing software such as Octave or Anaconda, ready for writing decoding modules.
4. Dan oscilloscope or spectrum analyzer with a USB interface, to connect the SDR receiver and visualize the received signal.

Which interfaces are used when interconnecting a transceiver and a linear power amplifier? (Choose all that apply.)

1. ARF interface
2. BPTT control interface
3. CALC interface
4. DAGC interface

Why is it necessary to connect an automatic level control (ALC) line when using a linear power amplifier?

1. Ato prevent over-driving that generates large intermodulation products interfering with adjacent frequencies
2. Bto reduce the amplifier’s harmonic distortion and prevent interference on harmonic frequencies
3. Cto equalize the signal’s frequency response and ensure the signal’s tonal quality remains unchanged
4. Dto make the amplified signal’s peak-to-average ratio better and easier to distinguish

When using an HF linear power amplifier in a multi-station contest environment, we try to improve the purity of the output signal so that other operators working on the harmonic (multiplied) band are not affected by harmonics. The usable method is:

1. Aconnect a notch filter operating at the harmonic band in series between the linear amplifier’s output and the antenna
2. Bconnect a band-pass filter operating at the harmonic band in series between the station’s RF output and the amplifier’s input
3. Cconnect a notch filter operating at the operating band in series between the linear amplifier’s output and the antenna
4. Dconnect a low-pass filter operating at the harmonic band in series between the station’s RF output and the amplifier’s input

The general method for adjusting an electron-tube (vacuum-tube) HF linear power amplifier is:

1. Aadjust “Tune” to minimize plate current, adjust “Load” to maximize output power, then fine-tune several times
2. Badjust “Tune” to maximize plate current, adjust “Load” to maximize output power, then fine-tune several times
3. Cadjust “Tune” to maximize output power, adjust “Load” to minimize the SWR at the antenna end, then fine-tune several times
4. Dadjust “Tune” to minimize the SWR at the antenna end, adjust “Load” to maximize output power, then fine-tune several times

Properly produced electron-tube HF linear amplifiers generally connect a very large inductance RF choke to ground at the RF output. Its function is:

1. Ato DC-ground the output end, so that when the internal plate-coupling capacitor fails (breaks down) it shorts the exposed DC high voltage and helps blow the AC supply line fuse
2. Bto DC-ground the output end. This can both bleed off lightning current and block QRN from static discharge from entering the receiver, thereby ensuring normal reception
3. Cas part of the amplifier’s tuning/matching circuit, which increases the tuning circuit’s inductive reactance and thereby broadens the impedance-matching range on the 160 m and 80 m bands
4. Dto bypass lower-frequency signals. For example, to prevent strong MF broadcast signals from entering the receiver via the antenna

The inner side of the chassis cover of an electron-tube linear amplifier usually has an interlock switch. Removing the cover immediately opens the switch. The function of this switch is:

1. Ato disconnect the mains input, reducing the possibility of maintenance personnel accidentally touching the high voltage inside
2. Bto disconnect the RF input, preventing high-power RF energy inside from burning the maintainer
3. Cto disconnect the filament supply, preventing the tube from continuing to heat and hindering maintenance
4. Dto disconnect the fan power, preventing the spinning impeller from injuring the person working underneath