Radio Frequency (RF) Spectrum is the range of electromagnetic waves used for communication. It covers everything from AM radio to Wi-Fi to satellite signals. Ham radio uses specific slices of this spectrum, legally assigned by governments and international agreements.

Let’s break it down in plain English:

The Big Picture

The RF spectrum is divided into bands based on frequency:

Band	Frequency	Range
HF	3-30 MHz	"Shortwave" - long-distance radio
VHF	30-300 MHz	"Line of sight" - local comms
UHF	300-3,000 MHz	"Urban/local" - high clarity, short range
SHF	3-30 GHz	Microwave - satellites, Wi-Fi, radar

HF, VHF, UHF: What's the Difference?

HF – High Frequency (3–30 MHz)

Nickname: “Shortwave”
Range: Thousands of miles using skywave/ionospheric reflection
Use: Great for international contacts, emergency comms, and low-power (QRP) work.
Ham Bands: 80m, 40m, 20m, 15m, 10m, etc.
Behavior: Reflects off the ionosphere, especially at night.
Downside: Needs longer antennas, subject to noise, requires more knowledge.

VHF – Very High Frequency (30–300 MHz)

Nickname: “Local Line-of-Sight”
Range: Typically 30–100 miles, more with repeaters or special conditions
Use: Ideal for local chats, public service, emergency nets
Ham Band: 2 meters (144–148 MHz)
Behavior: Generally doesn’t bounce off the atmosphere, limited by hills and buildings
Upside: Easier to work with; most beginner handheld radios (HTs) use this band

UHF – Ultra High Frequency (300 MHz – 3 GHz)

Nickname: “High Clarity, Short Range”
Range: A few miles normally, more with good setup
Use: Urban communication, repeaters, indoor coverage
Ham Band: 70 cm (420–450 MHz)
Behavior: Great inside buildings, but blocked more easily than VHF outdoors
Upside: Compact antennas, sharp signal quality

A Beginner’s Analogy

HF is like bass – deep, travels far, but slower and affected by environment.
VHF is like midrange tones – clear, dependable, covers a room or two.
UHF is like treble – crisp, great in small spaces, fades fast in open air.

Where Ham Radio Fits in the RF Spectrum

Ham operators get specific slices in each of these bands. These “ham bands” are like neighborhoods where you're legally allowed to transmit (after licensing). For example:

Note: “Meter” names come from the wavelength of the signal, not the frequency.

Ham Band Name	Actual Frequency Range (MHz)	Use Case
80 meters	3.5-4.0	Nighttime HF, regional contacts
40 meters	7.0-7.3	General Purpose HF band
20 meters	14.0-14.35	Daytime HF, worldwide comms
10 meters	28.0-29.7	HF/VHF hybrid, open during solar peak
2 meters	144-148	Local, reliable VHF communication
70 centimeters	420-450	Short-range, UHF repeaters

Why It Matters

Knowing the band layout helps you:

Choose the right radio and antenna
Understand what range to expect
Pick the right time and band for DX (long-distance) or local chatting
Avoid accidentally transmitting outside your privileges

What You Can Do As a New Ham

Technician License gives you access to:

All of 2m (VHF) and 70cm (UHF)
A small slice of 10m HF

General License opens the door to the “core” HF bands (40m, 20m, etc.)
Extra License gives access to everything

Lesson 4: RF Spectrum Overview (Just the Basics)