UK Amateur Radio Foundation Study Guide 2026

The Foundation exam

In the UK, Ofcom issues amateur radio licences. There are three levels: Foundation, Intermediate and Full. The RSGB (Radio Society of Great Britain) sets and runs the exams. Foundation is the entry level.

Questions in each section

• There is no mandatory practical assessment. It was removed in 2021.
• During the exam you get a reference booklet with an extract of the licence schedule, band plans and a decibel table.
• After you pass, apply for your licence and call sign on the Ofcom website, using your RSGB candidate number.

Your licence and the 2024 changes

The amateur licence is for non-commercial self-training. You may not use it for business or advertising. It covers the UK, the Channel Islands and the Isle of Man, but not other countries.

In December 2023 Ofcom published its decision on a new licensing framework. Ofcom expected the new terms to apply from February 2024. For Foundation licensees, the main changes were:

• Power raised to 25 W PEP in most Foundation bands.
• Foundation licensees may now build their own equipment.
• Access to the 2.4 GHz and 5 GHz bands, at up to 2 W.
• Remote control over the internet is allowed, if the link is secure.
• Regional Secondary Locators (RSLs) are optional for Foundation call signs.
• Unlicensed people may operate under a licensee's direct supervision.

Some Foundation bands and powers

Some bands are shared. Where amateurs have secondary status, you must not cause interference to primary users and you must accept interference from them.

Keeping your licence

• The licence is for life.
• Tell Ofcom straight away about a change of name or address.
• Confirm your licence details at least every five years, or the licence can be revoked.
• New Foundation call signs are issued in the M7 series.

Identification and operating rules

Identification

Give your call sign so others know who is transmitting. You must identify when you change frequency, change mode (for example FM, SSB, CW or a data mode such as FT8), change the supervisor, or change the RSL you use.

Regional Secondary Locators

An RSL is a letter in your call sign that shows where you are. It is optional for Foundation call signs, but if you use it, use the right one.

Messages

• Send messages only to other amateur stations.
• Do not broadcast to the general public. A CQ call is allowed.
• Encryption is not allowed, except at the request of a User Service or to control an amateur satellite. Morse code is not a secret code.

Supervision, interference and EMF

• Only you, or someone under your direct supervision, may use your radio equipment. The station uses your call sign and your licence terms.
• If you cause undue interference, a person authorised by Ofcom can inspect your station and require changes, limits or closedown.
• Do an EMF assessment based on the ICNIRP limits and keep a record of it, even if you decide no action is needed.
• For remote control, the link must be secure so no one else can take over, and you must be able to stop transmissions promptly.

Technical basics

• Current is a flow of electrons, measured in amperes. Voltage is measured in volts.
• Conductors such as copper and brass let current flow. Insulators such as plastic, rubber, glass and ceramics do not, but wet insulators can conduct.
• Resistance is measured in ohms. Ohm's law: voltage = current x resistance.
• Power is measured in watts. Power = voltage x current.
• DC flows one way. AC changes direction. UK mains is AC at 50 Hz.
• Speech on a radio voice channel needs about 300 Hz to 3 kHz.
• As frequency goes up, wavelength gets shorter. Radio waves travel at about 300 000 000 metres per second. At 145 MHz the wavelength is about 2 metres.
• Battery capacity is given in ampere-hours (Ah). Always connect batteries and supplies with the right polarity.

Transmitters and receivers

A transmitter puts information onto a radio frequency carrier by modulation. A receiver takes it off again by demodulation.

1. Transmitter: microphone, audio amplifier, frequency generator, modulator, RF power amplifier, feeder, antenna.
2. Receiver: antenna, feeder, tuning and RF amplifier, demodulator, audio amplifier, loudspeaker or headphones.

• AM varies the strength of the carrier. FM varies its frequency.
• SSB sends one sideband and no carrier, so it uses about half the bandwidth of AM.
• Bandwidth from narrowest to widest: CW, SSB, AM, FM.
• Overmodulation or overdriving spreads your signal into nearby channels.
• Harmonics are unwanted signals at multiples of your frequency. Filters reduce them.
• Sensitivity is hearing weak signals. Selectivity is rejecting signals outside the wanted bandwidth.

Feeders, antennas and propagation

Feeders and antennas

• Coaxial cable is the most common feeder because its screen keeps the signal inside. Amateur coax is usually 50 ohms. TV coax is 75 ohms.
• Feeder loss rises with length and frequency.
• A balun connects a balanced dipole to unbalanced coax.
• A Yagi has a driven element, a longer reflector and a shorter director. It is directional.
• A vertical quarter-wave ground plane radiates equally in all horizontal directions.
• A high SWR reading suggests a fault or mismatch in the antenna or feeder.
• An ATU changes the impedance the transmitter sees. It does not tune the antenna itself.
• At VHF and UHF, use the same polarisation as the other station.
• Know the common connectors: BNC, N type, SMA and PL259.

Propagation

• VHF and UHF range is close to line of sight. Hills and buildings block signals. Higher, outdoor antennas help.
• HF signals are refracted by the ionosphere, about 70 to 400 km up, which is formed by ultraviolet light from the sun.
• The D layer absorbs lower HF frequencies by day and disappears at night.
• The F2 layer gives the longest single hops.
• Sporadic E can suddenly give long-distance contacts on 28 MHz and VHF.

Electromagnetic compatibility (EMC)

EMC means equipment can work together without interfering. All electronic equipment can give off and pick up RF. Immunity is how well equipment works in a strong RF field.

• More power means more chance of interference.
• AM and SSB are most likely to cause problems. FM and some data modes are less likely.
• Your signal can get into a neighbour's equipment along mains wiring, TV downleads, phone lines and long speaker leads.
• Non-radio sources such as LED lighting, solar PV inverters, switch-mode supplies, motors and thermostats can cause interference to you.
• Fit ferrite chokes and filters on the leads, close to the affected equipment.
• Transmit into a dummy load to find out whether the problem comes from your antenna or from RF leaking along other leads.
• Keep a station log. It helps when you look into an interference complaint.

Operating practices

• Listen first and ask if the frequency is in use before you call.
• Use a calling channel only to make contact, then move to another frequency.
• To call on VHF FM, say CQ a couple of times, give your call sign, then listen.
• Follow the band plan. It sets aside parts of each band for modes such as CW, data and voice, and for satellites (around 145.8 to 146.0 MHz on 2 m).
• Use LSB below 10 MHz and USB above 10 MHz for SSB voice.
• Voice signal reports use readability (1 to 5) and strength (1 to 9). A 59 is perfectly readable and very strong.
• Repeaters often have a time-out timer, so keep your overs short. CTCSS is the recommended access method, as toneburst access is being withdrawn.

Safety

• High voltages can cause electrocution. Switch off and unplug before working on equipment.
• UK plug wiring: brown to live, blue to neutral, green and yellow to earth.
• An RCD or RCBO trips on small leakage currents to earth, which a fuse does not detect.
• Keep a hot soldering iron in its stand.
• Wear eye protection when drilling metal.
• Have a helper steady the ladder when you work on antennas.
• Never touch a transmitting antenna: you could get a shock or RF burn.
• The main health effect of strong RF is heating of body tissue. ICNIRP advises on safe exposure levels.