Andrew Vine, M0GJH

1. Andrew Vine, M0GJH

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

3. Licensing Conditions Types of Amateur Licence Foundation Intermediate Advanced

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

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

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

7. 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

8. 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

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

10. 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

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

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

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

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

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

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

17. 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

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

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

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

21. 1 2 4 3 Transmitters and Receivers Modulator Audio Stage RF power amplifier Frequency Generator

22. Need to remember 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

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

24. Common modulation modes :- Voice AM Carrier and two side bands SSB Single side band FM Frequency Modulation Morse code Carrier Frequency Shift Keying (FSK) on SSB or FM Data

25. 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

26. 1 2 3 The Receiver Loudspeaker Detection Tuning and rf amplifier Audio amplifier

27. 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.

28. Plugs BNC PL259

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

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

31. Long Wire

32. Effective Radiated Power (“erp”) 10W Gain 10 dB 100W = erp Gain in dB = 10Log10 (Power Out) (Power In) 3 dB = 2 times 6 dB = 4 times 9 dB = 8 times 10 dB = 10 times

33. Points on Antennas If an antenna is not correctly designed for the frequency it will not match the transmitter and will not work effectively 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.

37. Balanced and unbalanced ¼ λ ¼ λ

38. Balanced and unbalanced ¼ λ ¼ λ Balun

39. i v ¼ λ ¼ λ StandingWave Ratio 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).

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

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

42. Dummy Loads

43. 50 ohm dummy load 10 x 1W resistors Each resistor = 500Ω

44. 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

45. 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

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

47. Ionosphere basics 400 Km 70 Km 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.

48. EMC Electro magnetic Compatibility 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

49. EMC 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.

50. Chelmsford Slides