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Amateur Extra: Variable-Length Coding

PSK Traces

Which of the following HF digital modes uses variable-length coding for bandwidth efficiency? A. RTTYB. PACTORC. MT63D. PSK31 Now, I guess this answers my question about last weeks Extra question. Mainly why is it important.  It’s important because it does matter in transmission efficiency.  So which mode would be a good and efficient method of … Read more

General: Sine Wave Oscillators

RC phase shift oscillator

What are the basic components of virtually all sine wave oscillators? A. An amplifier and a dividerB. A frequency multiplier and a mixerC. A circulator and a filter operating in a feed-forward loopD. A filter and an amplifier operating in a feedback loop To answer this question, lets look at what makes up a sine … Read more

Amateur Extra: Using ASCII Code

What is one advantage of using ASCII code for data communications? A. It includes built in error correction featuresB. It contains fewer information bits per character than any other codeC. It is possible to transmit both upper and lower case textD. It uses one character as a shift code to send numeric and special characters … Read more

General: Uses For An Antenna Analyzer

What is a use for an antenna analyzer other than measuring the SWR of an antenna system? A. Measuring the front to back ratio of an antennaB. Measuring the turns ratio of a power transformerC. Determining the impedance of an unknown or unmarked coaxial cableD. Determining the gain of a directional antenna Well, you’re not … Read more

General: Peak Inverse Voltage

Halfwave rectifier

What is the peak-inverse-voltage across the rectifier in a half-wave power supply? A. One-half the normal peak output voltage of the power supplyB. One-half the normal output voltage of the power supplyC. Equal to the normal output voltage of the power supplyD. Two times the normal peak output voltage of the power supply [G7A04] To … Read more

General: Station Log Information

Station Log Information QSL Card

What information is traditionally contained in a station log? [G2D09] A. Date and time of contactB. Band and/or frequency of the contactC. Call sign of station contacted and the signal report givenD. All of these choices are correct When keeping logs for your station, you need certain pieces of information for the contact, or QSO … Read more

Technician: Amplifier Components

Amplifier Components

Which of the following electronic components can amplify signals? [T6B05] A. Transistor B. Variable resistor C. Electrolytic capacitor D. Multi-cell battery The answer is, as luck would have it, A. Transistor.  The transistor is probably the miracle of 20th century technology.  It’s an amplifier, a switch, and so much more. None of the other components … Read more

General: Schottky Diode

Schottky diode

Which of the following is an advantage of using a Schottky diode in an RF switching circuit rather than a standard silicon diode? [G6A06] A. Lower capacitance B. Lower inductance C. Longer switching times D. Higher breakdown voltage First off, we need to know the difference between a Schottky diode and a standard silicon diode.  … Read more