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What are 5 components of HF system? ---------CORRECT ANSWER--------- --------Receiver transmitter, antenna, antenna coupler, control head, and audio system Which part of HF system creates sidetone that is sent to audio system? ---- -----CORRECT ANSWER-----------------Receiver transmitter What component is used to electrically change length of antenna to allow large bandwidths of frequency to use antenna? ---------CORRECT ANSWER-----------------Antenna coupler (couples HF system to antenna) The antenna coupler is also used to perform which two functions? --------- CORRECT ANSWER-----------------Match impedance and monitor SWR Which part of HF system rough tunes coupler? ---------CORRECT ANSWER-----------------Receiver transmitter FM guard bands are _____ kHz at upper and lower boundary of each channel and guard against interference ---------CORRECT ANSWER--------- --------24kHz
What are two types of FM generation? ---------CORRECT ANSWER---------- -------Direct (capacitor) and indirect (phase modulation) What are the primary advantages of FM? ---------CORRECT ANSWER------- ----------Greater noise suppression, high fidelity (stereo) reception, less interference (limits capture effect), reduced transmitter power to cover assigned area When the carrier is modulated, where is the information located? --------- CORRECT ANSWER-----------------Upper and lower sidebands of composite signal What is the difference frequency known as? ---------CORRECT ANSWER--- --------------Intermediate Frequency What is the receivers ability to faithfully reproduce a desired signal is based on what two things? ---------CORRECT ANSWER-----------------Its sensitivity and selectivity What does Phase Lock Loop do? ---------CORRECT ANSWER----------------- Compares output of VCO with a reference frequency What happens if the output of VCO is different than the reference frequency? ---------CORRECT ANSWER-----------------DC controlling voltage is generated to steer VCO to correct output
FM IF signal is at what frequency? ---------CORRECT ANSWER--------------- --10 MHz What type of tuning uses filtering, mixing, multiplication to provide specific frequency? ---------CORRECT ANSWER-----------------Direct synthesis What is purpose of RF section? ---------CORRECT ANSWER----------------- Eliminate all frequencies except tuned RF What is a significant advantage of SSB? ---------CORRECT ANSWER-------- ---------Efficient use of RF spectrum SSB transmissions limit the effects of what? ---------CORRECT ANSWER--- --------------Selective feeding What are 5 types of SSB? ---------CORRECT ANSWER-----------------Pilot carrier, vestigial sideband, lincompex, ISB, Standard SSB What type of SSB is used by the military? ---------CORRECT ANSWER------ -----------ISB What type of SSB is used by amateur radio operators? ---------CORRECT ANSWER-----------------Standard SSB
What type of SSB is used by TV video transmissions and conserves bandwidth? ---------CORRECT ANSWER-----------------Vestigial What type of SSB has two sidebands that can each carry completely different intelligence? - --------CORRECT ANSWER-----------------ISB What is the purpose of balanced modulator? ---------CORRECT ANSWER-- ---------------Eliminates/suppresses carrier What is the heart of sideband generation? ---------CORRECT ANSWER----- ------------Balanced modulator What are 3 methods for SSB generation? ---------CORRECT ANSWER------ -----------Filter method, phase method, Third/Weaver method What is a unique aspect of SSB? ---------CORRECT ANSWER----------------- Must recreate carrier in order for intel to be detected What frequency range is used by CB? ---------CORRECT ANSWER----------- ------26.965-27.405 MHz What is heterodyning? ---------CORRECT ANSWER-----------------Combining 2 frequencies to convert to new frequency without altering intel in original
What type of HF has the carrier reinserted prior to transmission? --------- CORRECT ANSWER-----------------AME What type of HF removes both LSB and carrier and is more efficient than AM with smaller bandwidth? ---------CORRECT ANSWER-----------------USB What type of HF is modulated by a 1kHz tone and whose transmit frequency is 1 kHz lower than carrier? ---------CORRECT ANSWER----------- ------LSB What types of HF only output power when mic is keyed and user talks? ----- ----CORRECT ANSWER-----------------USB and LSB What are two types of phase detectors? ---------CORRECT ANSWER-------- ---------Sequential (digital) and Multiplier (no memory) What is the a general rule of thumb regarding the sun and frequency? ------- --CORRECT ANSWER-----------------The higher the sun the higher the frequency FM has a carrier and a _____ number of sidebands ---------CORRECT ANSWER-----------------Infinite FM sidebands have _____ amplitudes and are always an _____ distance from center (carrier) frequency ---------CORRECT ANSWER----------------- equal amplitude, equal distance from carrier
What is the bandwidth of narrow band FM? ---------CORRECT ANSWER---- -------------10 to 30 kHz Why is NBFM reduced bandwidth? ---------CORRECT ANSWER--------------- --To accommodate signal/voice transmissions What is primary advantage of NBFM? ---------CORRECT ANSWER----------- ------RF spectrum conservation What are four steps of TS NBFM? ---------CORRECT ANSWER----------------
- Assess, troubleshoot, repair, re-assess What frequency are NBFM guard bands? ---------CORRECT ANSWER------ -----------Two 5kHz guard bands Shorts usually also cause what? ---------CORRECT ANSWER----------------- Opens What are diodes susceptible to? ---------CORRECT ANSWER----------------- Heat
