Andrew Vine, M0GJH

Amateur radio Recall that the amateur licence is for self-training in radio communications and is of a non- commercial nature. Nature of amateur radio

Licensing Conditions Types of Amateur Licence Foundation Intermediate Advanced

Recall the format of the current Foundation, Intermediate and Full call signs. Format of Amateur call signs M3ABC 2E0ABC M0ABC

Know the Regional Secondary Identifiers and how they are used with a Foundation licence. D I M W J U Isle of Man Northern Ireland Scotland Wales Jersey Guernsey M3ABC becomes Mx3ABC where x = D, I, M etc Note, there is no Regional Secondary Identifier for England

Mobile and Portable operation / P-e.g. MW3ABC/P / M-e.g M3ABC / M

A typical question Your call sign is M3ABC. You go to the Isle of Man on holiday and want to operate from your holiday accommodation. What call sign do you use ? MD3ABC / P

You live in Scotland and your callsign is MM3ABC. On a visit to England you want to operate with a hand held set whilst walking in the Lake district. What call sign do you use ? M3ABC / M

The CQ Call CQ CQ CQ This is M3ABC, M3ABC calling CQ CQ CQ This is M3ABC calling CQ and standing by

Recall the requirements for station identification. During initial CQ Calls At beginning and end of each period of communication After 15 minutes Transmission on a new frequency By same type of transmission and on same frequency

Only send messages to other amateurs. Some do’s and don’ts No secret codes No broadcasting No transmission of music

Only the licensee personally may use the station. Must notify Ofcom of change of address. Ofcom local office officials have the right to close down or restrict operation. Some do’s and don’ts Ofcom is the independent regulator and competition authority for the UK communications industries, with responsibilities across television, radio, telecommunications and wireless communications services

The Log Book Date Time (UTC) of :- first transmission last transmission Changes to frequency, band, class or power Frequency or Band Mode Power

The Log Book Initial CQ Calls Call signs of stations worked Location when at a temporary location

Need to be able to interpret :- The Schedule to the Licence Band Plans Frequency Allocation Table

Technical Basics Identify the units of, and abbreviations for, Voltage (Potential Difference), Current, Power and Resistance. & OhmsVolts,Amps,Watts Note: Prefixes milli, kilo and Mega may be used.

Recall the relationship between Voltage (Potential difference), Current and Power Power = Volts x Amps W = V x A Recall the relationship between Voltage (Potential difference), Current and Resistance Volts = Amps x Resistance V = I x R

Batteries Polarity can be important Direct Current / Alternating Current (DC / AC) AC easier to generate and change voltage

Frequency mains supply UHF VHF HF normal hearing audio communication 50Hz (230 volts) 100Hz - 15kHz 300Hz - 3kHz 3MHz – 30MHz 30MHz – 300MHz 300MHz – 3000MHz

Frequency Allocation Table (discuss chart) Frequency and Wavelength (discuss chart) No need to know c = f x λ at this level

Transmitters and Receivers Audio Stage Modulator Frequency Generator RF power amplifier

frequency generation stage(s) (e.g. oscillator(s)) in a transmitter defines the frequency on which the transmitter operates. incorrect setting of these stages can result in operation outside the amateur band and interference to other users Need to remember

audio (or data) signal is modulated on to the radio frequency “carrier” in the modulation stage of the transmitter FMAM

Common modulation modes :- AMCarrier and two side bands SSBSingle side band FM Voice Frequency Modulation Morse codeCarrier Data Frequency Shift Keying (FSK) on SSB or FM

Transmitter considerations the r.f. power amplifier output must be connected to a correctly matched antenna to work properly and that use of the wrong antenna can result in damage to the transmitter excessive amplitude modulation causes distorted output and interference to adjacent channels excessive frequency deviation will cause interference to adjacent channels need to ensure that the microphone gain (where fitted) is correctly adjusted

12 Tuning and rf amplifier Detection Audio amplifier The Receiver 3 Loudspeaker

Feeder requirements Need to use the correct cable for r.f. signals. Coaxial cable is most widely used because of its screening properties plugs and sockets for r.f. should be of the correct type and that the braid of coaxial cable must be correctly connected to minimise r.f. signals getting into or out of the cable.

Plugs BNC PL259

Antennas the purpose of an antenna is to convert electrical signals into radio waves, and vice-versa. ¼ λ ½ wave dipole

λ/4 ground plane 5/8 λ Yagi Polarisation ? Radiation pattern ? Some more antennas

Long Wire

10WGain 10 dB100W = erp Effective Radiated Power (“erp”) Gain in dB = 10Log 10 (Power Out) (Power In) 3 dB = 2 times6 dB = 4 times9 dB = 8 times 10 dB = 10 times

If an antenna is not correctly designed for the frequency it will not match the transmitter and will not work effectively Points on Antennas Where an antenna has not been designed for the particular frequency, an ATU (antenna tuning unit) makes it possible for the antenna to accept power from the transmitter.

Balanced and unbalanced ¼ λ

Balanced and unbalanced ¼ λ Balun

Standing Wave Ratio ¼ λ i v The amplitude of the standing wave varies between a minimum and maximum. The ratio of the maximum to minimum value is known as the voltage standing wave ratio (VSWR) or standing wave ratio (SWR).

6 7 8 SWR v Frequency for a dipole 20.22m in length

A high SWR (measured at the transmitter) is an indication of a fault in the antenna or feeder (and not the transmitter SWR

Dummy Loads

50 ohm dummy load 10 x 1W resistors Each resistor =500Ω

Radio propagation basics radio waves travel in straight lines, unless diffracted or reflected. radio waves get weaker as they spread out (inverse square law) v.h.f. and u.h.f. hills cause “shadows” and waves get weaker when penetrating buildings but glass windows are more transparent to radio waves

Radio propagation basics range achieved at v.h.f./u.h.f. is dependent on antenna height, a clear path and transmitter power. Higher antennas are preferable to higher power, as they improve both transmit and receive performance. Outdoor antennas will perform better than indoor antennas. at v.h.f./u.h.f., range decreases as frequency increases and that in general, v.h.f./u.h.f. waves have a range not much beyond “line of sight

Ionosphere basics 70 Km 400 Km Electrons are stripped off the gas molecules, resulting in ions, by the ultra-violet radiation of the Sun as well as incident X-rays

On h.f. almost all communication relies on the waves being reflected by the ionosphere. H.f. can provide world-wide propagation depending on how well the ionosphere bends the waves back to the earth. This varies with frequency, time of day and season. 400 Km 70 Km Ionosphere basics

EMCElectromagneticCompatibility the avoidance of interference between various pieces of electronic equipment radio transmitters can cause interference to nearby electronic and radio equipment radio receivers can also suffer from interference from local sources

interference occurs through local radio transmissions being conveyed to the affected equipment through pick up in house wiring, TV antenna down-leads, telephone wiring etc., and (particularly at v.h.f./u.h.f.) by direct pick-up in the internal circuits of the affected equipment itself. EMC

Chelmsford Slides

Operating practices How to make a CQ call - HF 1) Listen 2) Check that the frequency is not being used 3) Call CQ

Operating practices How to make a CQ call - VHF 1) Find a channel that is not being used 2) Switch to the calling channel 3) Listen and then ask if the frequency is in use 4) Call CQ 5) Having established contact switch to a vacant channel

Operating practices – need to know Phonetic alphabet What repeaters are about ? Why Band Plans are used ? Connecting anything other than the supplied microphone (e.g. packet radio, TNCs) to the transmitter requires correct operation of the PTT line and correct audio signal levels.

Phonetic Alphabet Sierra Tango Uniform Victor Whiskey Xray Yankee Zulu Alpha Bravo Charlie Delta Echo Foxtrot Golf Hotel India Juliet Kilo Lima Mike November Oscar Papa Quebec Romeo

Repeaters Output Frequency MHz Input Frequency MHz Access 1750Hz initial access GB3GF