License Exam Quiz #357

de Steve, AE8AT 

James West, co-inventor of the electret microphone, was born February 10, 1931 in the home built by his father because the nearby hospital would only admit white patients. He served in the Army during the Korean War, receiving a Purple Heart. A professor at Johns Hopkins University in the Department of Electrical and Computer Engineering. He is a Bell Laboratories Fellow. George W. Bush awarded him the National Medal of Technology and Innovation in 2006. He holds around 250 patents. The electret microphone required no DC bias allowing it to be smaller and lighter than conventional microphones while providing excellent sensitivity and accuracy. Today the electret microphone design is roughly 90% of all microphones produced and everywhere from amateur radio to baby monitors. None of the question pools had a question specifically on the electret, so we will be taking some liberties!

T4B01 What is the effect of excessive microphone gain on SSB transmissions?

A. Frequency instability

B. Distorted transmitted audio

C. Increased SWR

D. All these choices are correct

G2A12 What control is typically adjusted for proper ALC setting on a single sideband transceiver?

A. RF clipping level

B. Transmit audio or microphone gain

C. Antenna inductance or capacitance

D. Attenuator level

E7H02 What is a microphonic?

A. An IC used for amplifying microphone signals

B. Distortion caused by RF pickup on the microphone cable

C. Changes in oscillator frequency caused by mechanical vibration

D. Excess loading of the microphone by an oscillator

Answers:

T4B01 = B

G2A12 = B

E7H02 = C