Radio Wave Properties and Characteristics

The highest ionization levels are found in areas closer to the equator.

Ionization levels increase proportionally as you move further away from the Earth's surface.

Ionization is at its lowest around midnight because the Earth's side facing the sun is the most ionized.

The E-layer is higher at night due to lower ionization levels, causing radio waves to reflect further.

The frequency required for HF communication in low latitudes is lower than the frequency needed in high latitudes.

The bandwidth produced when a carrier wave is amplitude modulated is twice the frequency of the modulating signal.

Single sideband (SSB) emissions offer multiple advantages.

FM modulates the frequency of the carrier wave based on the frequency of the modulating signal.

The initial range calculation at the receiver before correction for receiver and satellite clock errors.

The C/A (Civilian Access) code is primarily used for civilian GPS applications. It is a weaker signal but provides a wider reception area. The P (Precision) code is used for military applications, and while it transmits a stronger signal it is restricted to authorized users.

RAIM stands for Receiver Autonomous Integrity Monitoring. It's a crucial safety feature that evaluates the health and reliability of the received GPS signals, ensuring their accuracy.

A non-precision approach usually involves using either the aircraft's barometric altitude or the radio altimeter height to determine the minimum descent altitude (MDA). This helps ensure a safe landing.

Satellite shadow can temporarily degrade GPS accuracy, and although the receiver can switch to other satellites, it's likely that some GPS accuracy will temporarily be lost.

The phase difference between the reference and variable phase components of a VOR transmission, measured in degrees. It is used to determine the radial on which the aircraft is located.

A VOR receiver in an aircraft measures the phase difference from a DVOR. The measured phase difference is then converted to a radial using a formula, and the aircraft's position relative to the VOR is determined.

VORs broadcast a signal with a 30Hz frequency modulation, which is used to determine the aircraft's position relative to the VOR. This information is displayed on the RMI.

The theoretical maximum range of a VOR is calculated based on the height of the VOR antenna and the aircraft's altitude. The higher the aircraft is, the greater the range.

The OBS setting is used to select the desired radial when navigating with a VOR. To home to the VOR, the pilot should set the desired radial onto the OBS.

The RMI displays bearings of NDBs and VORs. To convert the RMI bearings to true bearings, the variation must be applied. For NDBs, the variation is applied at the beacon position. For VORs, the variation is applied at the aircraft position.

The pilot should set 210° on the OBS and on reaching the 030 radial should turn left onto a heading of 030° assuming zero wind.

On the RMI, the VOR is depicted by a

The NAVSTAR/GPS control segment is made up of three parts: the space segment (satellites), the user segment (receivers), and the ground segment (control stations).

The NAVSTAR/GPS constellation orbits at an altitude of 20,180 km with an inclination of 55 degrees.

The model of the earth used for NAVSTAR/GPS is a geodetic reference system called WGS84 (World Geodetic System 1984).

A minimum of four satellites are needed to determine a three-dimensional (3D) position fix using NAVSTAR/GPS.

The operational NAVSTAR/GPS constellation consists of 31 satellites, ensuring continuous global coverage.

The most accurate fixing information is obtained when one satellite is directly overhead and three others are spaced 120 degrees apart close to the horizon.

The most significant error source in GNSS is Geometric Dilution of Precision (GDOP), which is affected by satellite geometry and receiver location.

The purpose of pseudo-random noise (PRN) codes in NAVSTAR/GPS is to uniquely identify each satellite.

The top of the cloud detected by the radar is 31,000ft above sea level. The radar beam is tilted upward, and the aircraft currently flies at FL370. The difference between the altitude of the aircraft and the altitude of the cloud detected by the radar determines the height of the cloud.

FL370 is 37,000ft above sea level. 37,000 - 6,000 = 31,000 ft

A special SSR code is used to communicate with the ground controller to inform them of urgency or an ongoing issue. The codes are used to indicate specific situations that require immediate attention and communication. The code 7700 represents an emergency situation. Code 7600 indicates a radio failure. Code 7500 indicates unlawful interference, and code 2000 indicates IFR entering controlled airspace.

Secondary Surveillance Radar (SSR) functions by transmitting a pulse and receiving a reply from a transponder on the aircraft. SSR uses Pulse Modulation and Operates in the UHF band.

When the IDENT button is pressed on the SSR transponder, it causes a momentary display on the controller's screen, which means the aircraft is acknowledged by the controller.

The ground controller will request the pilot to cancel Mode C if there is a larger than 300 feet deviation between the reported altitude from the pilot's instrument and the altitude determined by the ground radar.

If there is no other "squawk" assigned, the SSR code should be set to 7500 for inbound or crossing flight.

Secondary radar requires a target transponder on the ground or aircraft that responds to the interrogation signal. This transponder is needed to generate the return signal for the radar system.

Airborne DME equipment has a unique feature that allows it to discern between pulses intended for it and those directed at other aircraft. Each aircraft has a unique identifier that helps the DME pick out the intended pulse.

A visual indicator on an Instrument Landing System (ILS) that indicates the aircraft is below the glide path and to the left of the centerline by maximum safe deviation. The aircraft needs to climb and adjust course to align with the glide path.

An aircraft flying outside the published coverage angle for ILS localizer signals on the inbound approach side will receive inaccurate, false, or even reversed course signals.

The specified maximum safe FLY UP indication on a 5-dot CDI (Course Deviation Indicator) is 2.5 dots above the centerline.

An aircraft using ILS approach beyond the coverage sectors of an ICAO standard system may receive inaccurate or reversed sense signals from both the localizer and glideslope needles. This can result in misleading course and altitude deviations, making a safe landing difficult.

The width of the radar beam is the primary factor determining its maximum range. A narrower beam allows the radar to detect targets at greater distances.

One of the main advantages of continuous wave radars is having no minimum range limitations. They can detect targets very close to the radar.

The Pulse Repetition Frequency (PRF) of a primary radar determines its maximum range. A lower PRF allows for longer pulses and greater range.

To double the range of a primary radar, you need to increase the power by a factor of four. Doubling the range means the signal travels twice as far, requiring four times the power to reach the same strength at the target