Amateur Extra: Estimating RF Fields

Which of the following would be a practical way to estimate whether the RF fields produced by an amateur radio station are within permissible MPE limits? [E0A03] A. Use a calibrated antenna analyzer B. Use a hand calculator plus Smith-chart equations to calculate the fields C. Use an antenna modeling program to calculate field strength … Read more

General: NVIS Height

At what height above ground is an NVIS antenna typically installed? [G9D03] A. As close to 1/2 wavelength as possible B. As close to one wavelength as possible C. Height is not critical as long as it is significantly more than 1/2 wavelength D. Between 1/10 and 1/4 wavelength First off, what the heck is … Read more

Amateur Extra: ASCII Parity Bit

What is the advantage of including a parity bit with an ASCII character stream? [E8C12] A. Faster transmission rate B. The signal can overpower interfering signals C. Foreign language characters can be sent D. Some types of errors can be detected The definition of a “parity bit” according to Wikipedia is: a bit added to … Read more

General: Overmodulation

Which of the following is an effect of overmodulation? [G8A08] A. Insufficient audio B. Insufficient bandwidth C. Frequency drift D. Excessive bandwidth The answer is D. Excessive bandwidth.  Now, for the purposes of getting this question correct on the exam, I’ll just say this: Just remember the connection between overmodulation and excessive bandwidth. The real … Read more

General: 80m Privileges

Which of the following frequencies is within the General Class portion of the 80-meter band? [G1A08, 97.301(d)] A. 1855 kHz B. 2560 kHz C. 3560 kHz D. 3650 kHz Well, we can eliminate answers A. 1855 kHz and B. 2560 kHz as neither one of those is in the 80-meter band, which is at 3500 … Read more

Technician: Spin Fading

What causes spin fading when referring to satellite signals? [T8B09] A. Circular polarized noise interference radiated from the sun B. Rotation of the satellite and its antennas C. Doppler shift of the received signal D. Interfering signals within the satellite uplink band Well, to start with, I suppose we should define “spin fading.”  Spin fading … Read more