A 19-section interactive guide to radio communications engineering — electromagnetic wave and propagation fundamentals, AM/FM and digital modulation techniques, RF transceiver design and link budgets, cellular network architecture (LTE and Wi-Fi 6), low-power wide-area networks for IoT, and satellite and navigation systems. Every figure gets its own full-size slide so waveforms, diagrams, and tables stay legible.
Chapters 1–3 build the physics foundation: the electromagnetic wave, free-space path loss, and antenna radiation patterns. Chapters 4–7 cover modulation techniques — AM and FM waveforms, AM vs. FM noise susceptibility, FM stereo baseband, and digital modulation (ASK, FSK, PSK, QAM). Chapters 8–9 cover RF system design — the RF transceiver block diagram and the wireless link budget. Chapters 10–13 cover cellular networks — frequency reuse, LTE architecture, the LTE OFDM resource grid, and Wi-Fi 6 OFDMA. Chapters 14–16 cover low-power wide-area networks for IoT — LoRa chirp spread spectrum, LoRaWAN network architecture and timing, and an LPWAN technology comparison. Chapters 17–19 cover satellite and navigation systems — satellite downlink link budgets, GNSS constellations, and ILS precision approach.
Use the Prev / Next buttons at the bottom, or press the arrow keys on your keyboard. Click the ☰ menu button in the top-right to open the table of contents and jump to any section. Each chapter’s reference figure follows immediately after its text as its own dedicated slide, so you can view the full diagram, waveform, or table at a readable size before moving to the next chapter.
RF and communications engineers who want a structured visual refresher on propagation, modulation, and system design fundamentals; wireless and IoT engineers evaluating cellular versus LPWAN tradeoffs for a connectivity project; and engineering students and FCC/radio licensing exam candidates building intuition for how EM waves, modulation schemes, and link budgets connect across broadcast, cellular, IoT, and satellite systems.
The guide covers 19 chapters across 6 parts: electromagnetic wave and propagation fundamentals, AM/FM/digital modulation techniques, RF transceiver design and link budgets, cellular network architecture (LTE and Wi-Fi 6), LPWAN/IoT connectivity (LoRaWAN), and satellite and navigation systems (satellite link budgets, GNSS, ILS).
AM (amplitude modulation) encodes the message in the carrier’s amplitude, which makes it simple to demodulate but highly susceptible to amplitude noise. FM (frequency modulation) encodes the message in the carrier’s instantaneous frequency, which lets an FM receiver largely reject amplitude noise, giving clearer audio at the cost of more transmission bandwidth.
A link budget adds transmit power and antenna gains, then subtracts free-space path loss and other losses, to calculate the power actually available at the receiver. Comparing that available power against the receiver’s minimum sensitivity yields the fade margin — the safety buffer against real-world variation like multipath fading and weather.
LTE connects User Equipment through an eNodeB base station to an all-IP Evolved Packet Core (Serving Gateway, Packet Data Network Gateway, Mobility Management Entity), using OFDM resource blocks for scheduling. Wi-Fi 6 adds OFDMA, which subdivides a single channel into smaller Resource Units so an access point can serve multiple users simultaneously instead of one at a time.
LoRaWAN uses LoRa chirp spread spectrum modulation, where a higher spreading factor spreads each symbol’s energy over more chirps, letting a receiver decode signals far below the noise floor at the cost of lower data rate. Its star-of-stars network architecture and Class A devices, which only listen for downlink messages in two brief windows after transmitting, give end devices multi-year battery life.
Disclaimer: This guide summarizes general radio communications engineering concepts for educational purposes only. Frequencies, link budget figures, and worked examples are illustrative. Always consult a licensed RF/communications engineer, the applicable FCC/ITU regulations, and equipment manufacturer specifications for actual system design.