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Chelmsford Amateur Radio Society & Essex Repeater Group M3 Foundation Course Repeaters/CTCSS

Chelmsford Amateur Radio Society & Essex Repeater Group M3 Foundation Course Repeaters/CTCSS. 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. Repeaters - Introduction.

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Chelmsford Amateur Radio Society & Essex Repeater Group M3 Foundation Course Repeaters/CTCSS

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  1. Chelmsford Amateur Radio Society & Essex Repeater Group M3 Foundation CourseRepeaters/CTCSS

  2. 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

  3. Repeaters - Introduction • Foundation Syllabus requires only a limited knowledge of CTCSS and how to access a repeater. • These slides enhance this as M3s will find Repeaters useful as they extend their range at VHF/UHF, and when mobile. • All repeaters are run under special permits/NoVs from the RA/RSGB/RMC

  4. Repeater Coverage 6m 2m • Coverage by 2m and 6m Repeaters • On 70cms there are lots ! • TV is mainly on 23cms

  5. 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 2m Shift is 600kHz, • On 70cms Shift is 1.6 or 7.6MHz • The shift direction varies with different bands - Up or Down • Standards require access by 1750Hz 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 2mins!

  6. Repeaters In Essex • Repeaters in central Essex run by Essex Repeater Group • 2m GB3DA, 70cms GB3ER, 6m GB3DB, 23cms GB3ZP (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

  7. CTCSS • CTCSS - Continuous Tone Coded Squelch System • A more modern alternative to 1750Hz Audio Tone burst • CTCSS is mandatory on 6m 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.

  8. CTCSS Frequencies • Each County in the UK nominally has a Tone allocated to it • Example: Essex is Tone-H 110.9Hz, but check as sometimes there are exceptions (eg in Clacton) Tone A = 67.0Hz Tone B = 71.9Hz Tone C = 77.0Hz Tone D = 82.5Hz Tone E = 88.5Hz Tone F = 94.8Hz Tone G = 103.5Hz Tone H = 110.9Hz Tone J = 118.8Hz

  9. CTCSS Map • Nominal allocations:- • There are exceptions • Check Repeater Details on RMC website or RSGB Yearbook

  10. GB3DA/GB3ER 2m/70cms Radios, Cavities & Logic

  11. Rx Tx Logic PSU GB3DB - 6m 6 Cavity Procomm Duplexer:- 3 on Tx 3 on Rx Nice But Pricey !

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