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Atmosphere, Ionoshpere & Radio Propagation Cheat Sheet (DRAFT) by

Atmosphere, Ionoshpere & Radio Propagation

This is a draft cheat sheet. It is a work in progress and is not finished yet.


gaseus envelope around a celestial body

Compos­ition of Earth's Atmosphere

Nitrogen = 78%
Oxygen = 21%
Argon = .9%
Carbon Bomboxide = .036%

Layers of Earth's Atmosphere

Tropos­phere -> Strato­sphere -> Mesosphere -> Ozone Layer of Doom -> Thermo­sphere


Higher region of the atmosphere which consti­tuents are no longer mixed by turbelence


Lower-­middle atmosphere which features homogenous mixture of atmosp­heric gases



Nebula Theory

Instellar cloud of gas collapsing under its own gravity. Explains all major features of the solar system and its exceptions

Solar Nebular Hypothesis

Rotating cloud of gas that contracts and flattens into a thin disc (leads to formation of planets) of gas and dust and the forming sun in the center.

Types of Planets

Joviaan: Large, have a lot of solids in their discs. Icy, rocky, metal core.
Terres­trial: Opposite of Jovian. (rocky metal core)

Space Debris

Comets: icy nucleus evaporated and sent to space by solar wind pressure
Meteor­oids: dust debris in space
Asteroids: rocky bodies of mass diameters less that 1km



Layers of the Sun

Radiative Layer: no electrons to trap photons (trans­parent)
Convective Layer: non ionized gases capture photons (opaque)
Photos­phere: density decrease
Chromo­shpere: can't see due to low density
Transition Zone

Hydros­tatic Equili­brium

Pressure balances the gravit­ational pull the center of the "­SPH­ERI­CAL­" body

Suns spots

Magnetic phenomena which occurs in the photos­phere. Occurs in pairs each member with opposite polarity.

Solar Prominence

Large bright gas features inside the sunspots. Horse shoe shape

Nuclear Fusion

H + H -> 2H + neutrino + positron
2H + H -> 3He + gamma ray
3He + 3He -> He + H + H + ENERGY


Region of thermo­sphere where the Sun's UV radiation ionizes oxygen molecule to a positive ion and free electron.

Layers of the Ionosphere

D Layer (night change)
E Layer (night change)
F1 Layer
F2 Layer

Virtual Height

Height from which the radio waves appear to reflect.

Critical Angle

Angle a radio wave must be transm­itted at to ensure reflection back to earth

Critical Freque­ncy­/Plasma Frequency

Highest frequency that at which radio wave transm­itted straight up will get reflected back.

Reasons for D E & F Layers

Solar Decomp­osi­tion: depends on the UV absorption of the atmosphere
Physics of Recomb­ina­torial factor­iza­tion: depends on the density of atoms
Atmosp­heric compos­ition: types of atoms at different heights

Differ­ential Energy Absorption

dI = (sigma­)(n­)(I­)(dS)
sigma = energy abosrption per unit volume
n = particle densit­ometer
I = intensity from the sun
dS = length of the layer

Ionization Rate

q = (sigma­)(p­)(n)(I)
p = number of particles


Plot of virtual height of the ionosphere vs the frequency
Produced by ionoso­ndes, transm­itting vertically up into atmosphere



Plasma Sheet

Slab-like particle population centered at the mid plane of the magneto tail. Divides into north and south lobes

Magnet­opause Current

Divides the earths magnetic field and plasma from solar wind. Induced current as a result of magnetic field deflection

Types of Particle Motion

Gyration: gyration of charge particles along geo magnetic field lines
Bounce: charged particles trapped in magnetic mirrors trapped in north and south
Drift: charged particles experience gradient and curvature drifts to the west for protons and east for electrons

Magnetic Mirror

Charged particles move in helical orbits at their cyclotron

Electr­oma­gnetic Wave

Radiation with electric and magnetic components oscill­ating at same frequency. Used to transmit inform­ation by wave motion.

Radio Waves

features air waves moving across the atmosp­here. reflects off of clouds or layers of ionosp­here.

Types of Radio Wave Propag­ation


Types of Radio Waves

Ground wave: follows the curvature of the earth on the surface as a result of earths electrical charac­ter­istics. (Direct and Reflected)
Sky wave: gets reflected by the ionoshpere
Space wave: shoots through to space

Amplutide Modulation

Amplitude of carrier wave is made to vary with the incoming signal.

Frequency modulation

Frequency of the carrier wave is made to vary with incoming signal



Types of Semico­nductor Atoms

Group III
B & Al
Group IV
Carbon & Silicon
Group V
Nitrogen & Phosphorus

Intrinstic Semico­ndu­ctors

Features 2 Group IV atoms in convalent bonds. Constant concen­tration of electr­on-hole pairs active at room temper­ature as a result of thermal energy. Ohmic relati­onship.

Extrinsic Semico­ndu­ctors

Atom with 5 valence electrons
Atom 3 valence electrons
Majority carrier electron
Majority carrier holes


Combine P and N type semico­ndu­ctors in a lattice.


Converting AC to DC. Remember half-wave and full wave rectif­ication




Power passing through unit area in unit solid angle about the normal to the area.


Power passing through the unit area.


Photons get deflected from incident direction by interm­ediary particles without energy loss.

Types of Scattering

Rayleigh: photons collide elasti­cally with the atmosp­heric molecules.
Non selective

Rayleigh Scattering

Why does the sky look blue?
light scatters in all directions at an intensity of (1+cos(2) (x))*lamba-4


Atmosp­heric mixture strong enough to lift up particles into the atmosphere

Types of Aerosols

Sea salts

Radiative Transfer Equation

-absor­ptivity + emittance - scattering out + scattering in