FM Repeater Setup



Personal experience gained from setting up Yaesu, Kenwood, Standard, Anytone and QYT (Chinese) transceivers for FM repeater operation proved to be a far from straight forward process. A common problem is that instruction manuals tell you what a transceiver will do, but provide little advice as to how and when all the different features should be used to achieve the results required. Too often, knowledge and experience is assumed as to why certain settings are required and when some features can be safely ignored. Using repeater programming software can initially add more complications than it resolves.

Whether you’re a Foundation licensee or experienced amateur returning to FM repeaters after some time, it’s hoped this sequence of instructions will lead to successful repeater operation. You will still need to consult the instruction manual for your particular transceiver, but at least you will know what you are looking for and why!

Know your local FM repeater parameters

  1. Obtain the callsign, output & input frequencies, & CTCSS (Continuous tone controlled squelch system) frequency for the repeater you wish to use. See the RSGB web site, On the Air, Operating, Beacons & Repeaters, UK repeaters, Lists, 2m Analogue (or 70cm Analogue).
  2. For example, the GB3VA (Vale of Aylesbury) repeater output frequency is 145.700MHz i.e. the frequency the repeater transmits on (& you listen to). The repeater input frequency is 145.100MHz i.e. the frequency the repeater receives on (& you therefore transmit on). The CTCSS frequency is 118.8Hz.
  3. Note also the difference in repeater TX/RX frequency is -600kHz and this is known as offset. Most 2m repeaters use a -600kHz offset. However, many 70cm repeaters use an offset of +1.6MHz. More recently installed 70cm repeaters may also use an offset of +7.6MHz or -9.0MHz. More follows later about the importance of offset, when setting up your transceiver.
  4. Additionally, note from the RSGB lists of repeaters that 12.5kHz channel spacing is used on both 2m & 70cm. Although not always published in the RSBG data, be aware there is a growing preference for repeaters to accept NBFM (narrow band frequency modulation) from users. This means you need to transmit with a narrow bandwidth of 2.5kHz, rather than a wider bandwidth of 5kHz.

Procedure for setting up a 2m FM transceiver

  1. Connect the transceiver to an antenna and set the transceiver to normal 2m VFO operation (VFO ‘A’ if both ‘A’ & ‘B’ VFOs are available). Stay in VFO mode for steps (5) to (13) and (17) below.
  2. Connect the transceiver to an antenna and set the transceiver to normal 2m VFO operation (VFO ‘A’ if both ‘A’ & ‘B’ VFOs are available). Stay in VFO mode for steps (5) to (13) and (17) below.
  3. Tune the VFO to say 145.7000MHz (GB3VA) and listen for the repeater. Even if no traffic is heard immediately, all repeaters announce themselves periodically in morse code; some have a pre-recorded audio announcement too.
  4. Tune the VFO to other frequencies and ensure the channel spacing is set to 12.5kHz, i.e. 145.7000, 145.7125, 145.7250, 145.7375 etc. This may be an automatic feature on your transceiver, otherwise refer to the instruction manual and select 12.5kHz channel spacing. Check that this channel spacing also applies to 70cm frequencies.
  5. Connect the transceiver to a dummy load and set to low power, say 5W.
  6. Check the transceiver RX/TX offset frequency is correctly set for 2m operation, i.e. -600kHz. If not, refer to repeater offsets in the instruction manual and set to -600kHz. Some transceivers will automatically apply the correct UK 2m offset frequency, when tuned to the repeater portion of the band. Most, if not all, transceivers allow this to be set by the operator. With the transceiver tuned to 145.7000MHz, press the PTT button and check that the frequency readout changes to 145.1000MHz, i.e. your transmit frequency.
  7. Check that the transceiver is set to NBFM, i.e. 2.5kHz bandwidth. If not, refer to transmitter bandwidth in the instruction manual and set accordingly.
  8. Finally, set the correct CTCSS frequency, according to the repeater you wish to access. For GB3VA, set the frequency to 118.8Hz. It is very important to note this CTCSS frequency is to be sent by the transceiver during transmission only; if inadvertently set for RX, or RX & TX, then nothing will be heard in the transceiver loudspeaker, although the repeater will be accessed during the combined RX & TX mode. Most transceivers have a table of preset CTCSS frequencies for the operator to choose from.
  9. As explained, set the transceiver to send the CTCSS frequency during transmission only. The instruction manual should provide detailed ‘button pushing’ instructions, together with a list of screen icons that will confirm the required settings have been made.
  10. Using GB3VA as an example and when satisfied that the:
    Transceiver received frequency is correct (145.7000MHz),
    Offset is correct (-600kHz),
    (c) Transceiver transmit frequency is correct (145.1000MHz),
    (d) CTCSS is correct (118.8Hz),
    (e) And the transmit bandwidth is 2.5kHz,

    Keep the transceiver in VFO mode, make no further adjustments and do not switch off the transceiver. Reconnect the antenna and assuming the frequency is free, operate the PTT button to transmit. The repeater should be accessed, assuming you are within range, and return a carrier/callsign. QSOs via the repeater should now be possible while you are still in VFO mode. Make no further changes or adjustments.
  11. Save all settings in the transceiver memory, according to the transceiver operating instructions.
  12. Keeping the transceiver in VFO mode, select other 2m repeaters and set up the appropriate receive frequency, offset and CTCSS frequency. Test and then save in new memories, as paras (13) & (14) above.
  13. Keeping the transceiver in VFO mode, select other 2m repeaters and set up the appropriate receive frequency, offset and CTCSS frequency. Test and then save in new memories, as paras (13) & (14) above.

Tone Burst History

  • Some early generation 2m repeaters use an audible 1750Hz tone burst to gain access, rather than a sub-audible CTCSS. GB3NL (N. London) is a typical example, although a CTCSS frequency of 82.5Hz is also listed for this repeater. The RX/TX offset is the usual -600kHz frequency. Older transceivers have a tone burst button on the front panel which is simply pressed for a few seconds at the beginning of transmission to gain repeater access; modern transceivers often incorporate the tone burst button into the speaker microphone buttons.

Interestingly, some New Zealand FM repeaters in sparsely populated areas use neither tone burst nor CTCSS and rely on the presence of a transmitted carrier only to access the repeater.

Procedure for setting up a 70cm FM transceiver

Procedures for setting up 70cm repeaters are generally similar to 2m, apart from setting the appropriate RX/TX offset frequencies of +1.6MHz, +7.6MHz & -9.0MHz, see para (3) above. A transmitted bandwidth of 2.5kHz is definitely preferred.

Using the VARC repeater GB3VR (Verulam Radio) as a 70cm example, set up your transceiver as follows:

  1. Transceiver received frequency is 430.8125MHz,
  2. Offset frequency is +7.6MHz,

(c) Transceiver transmit frequency is 438.4125MHz,

(d) CTCSS frequency is 67.0Hz,

(e) Transceiver transmit bandwidth is 2.5kHz.

Peter G3UHN 19.10.23

Secured By miniOrange