Chelmsford Amateur Radio Society Essex Repeater Group M

Chelmsford Amateur Radio Society & Essex Repeater Group M 3 Foundation Course Repeaters/CTCSS Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 1

Repeaters • Repeaters extend ranges across counties, over hills etc esp. for handheld and mobile users. • The UK has over 300 Voice and 40 TV Repeaters Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 2

Repeaters - Introduction • Foundation Syllabus requires only a limited knowledge of CTCSS and how to access a repeater. • These slides enhance this as M 3 s will find Repeaters useful as they extend their range at VHF/UHF, and when mobile. • All repeaters are run under special permits/No. Vs from the RA/RSGB/RMC Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 3

Repeater Coverage • Coverage by 2 m and 6 m Repeaters 2 m 6 m • On 70 cms there are lots ! • TV is mainly on 23 cms Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 4

Accessing Repeaters • Repeaters have a frequency shift between Input and Output so they can transmit at the same time as receiving and have ‘Logic’ for control , Morse idents etc – On 2 m Shift is 600 k. Hz, – On 70 cms Shift is 1. 6 or 7. 6 MHz • The shift direction varies with different bands - Up or Down • Standards require access by 1750 Hz Toneburst or CTCSS, and requires your callsign on every over. • Best to set Local Repeaters up in Radio Memories • Repeaters Timeout and cut audio - keep overs to 2 mins! Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 5

Repeaters In Essex • Repeaters in central Essex run by Essex Repeater Group • 2 m GB 3 DA, 70 cms GB 3 ER, 6 m GB 3 DB, 23 cms GB 3 ZP (soon) • ERG website: http: //www. essexrepeatergroup. org. uk/erg • Repeaters are not funded by the RSGB, they are run by volunteers. Regular users are encouraged to subscribe to repeater groups to help pay running costs, insurance etc • In North Essex repeaters are at Clacton/Braintree Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 6

CTCSS • CTCSS - Continuous Tone Coded Squelch System • A more modern alternative to 1750 Hz Audio Tone burst • CTCSS is mandatory on 6 m systems and newer repeaters • A low frequency tone is continuously transmitted as part of your Audio (almost sounds like faint mains hum) • A range of precise tone frequencies are defined and repeaters will only accept their official tone to block interference. • Repeaters also put CTCSS on their outputs, so users own radios can ignore unwanted signals. Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 7

CTCSS Frequencies • Each County in the UK nominally has a Tone allocated to it • Example: Essex is Tone-H 110. 9 Hz, but check as sometimes there are exceptions (eg in Clacton) Tone A = 67. 0 Hz Tone B = 71. 9 Hz Tone C = 77. 0 Hz Tone D = 82. 5 Hz Tone E = 88. 5 Hz Tone F = 94. 8 Hz Tone G = 103. 5 Hz Tone H = 110. 9 Hz Tone J = 118. 8 Hz Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 8

CTCSS Map • Nominal allocations: • There are exceptions • Check Repeater Details on RMC website or RSGB Yearbook Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 9

GB 3 DA/GB 3 ER 2 m/70 cms Radios, Cavities & Logic Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 10

GB 3 DB - 6 m 6 Cavity Procomm Duplexer: 3 on Tx 3 on Rx Rx Tx Logic PSU Nice But Pricey ! Chelmsford Amateur Radio Society M 3 Foundation Licence Course Murray Niman G 6 JYB Slide Set 8 Repeaters/CTCSS 11