When operating at an event NWHR often uses a repeater setup to allow remote mobile (or hand-held) stations to connect to the Control Point at a greater distance than a direct, or point to point, communication or to make connections where local geography works against us.
There are also many repeaters for general use around the UK and their details can be found here:
The repeater’s job is to listen on an input frequency and then transmit that same signal on a different output frequency. The mobile user will be listening/receiving on the repeater’s output frequency and transmitting on the input frequency. Usually the transmission will include a tone (CTCSS) to permit the activity through the repeater.
The difference between the input and output frequencies is called the Offset or Shift value and is often +/- 600kHz or other similar values. (600 kHz for a repeater on the 2M frequencies and 1.6 MHz on 70CM).
EG: GB3RD – the Reading 2M repeater, transmits on 145.675 MHz (the frequency we listen to), and receives on 145.075 MHz (the frequency on which we transmit), which is a negative (or minus) 600 kHz Shift. The CTCSS tone is 118.8 Hz.
You can watch the Foundation Training (the entry level for a Radio Amateur) on this topic below.
Setting up your own radio to use a repeater has a few simple steps. These steps are similar, but not identical, for every radio:
- Set your radio to listen to the repeater output (transmit) frequency. This is often as simple as using the keypad and entering the frequency (145.675 for Reading-GB3RD) or turning the frequency dial to that number.
- Then we have to set the Shift/Offset and Shift/Offset Direction. Some models call this “Duplex” and use DUP or DUP- for positive or negative repeater shifts.
- Your handset will have a menu button. Once pressed you’ll have access to the many settings and then it will be necessary to scroll, using up/down arrows, or turning the dial until you find the “Duplex”, “Offset”, or “Shift” option.
- Press Menu again to make changes to the value. This may be typing the value or turning the dial to the right value (600kHz for Reading-GB3RD). Press Menu to save the value
- Scroll again until you see the DUP/Offset/Shift +/- option. Press Menu, scroll up/down until you find the right option (negative “-” Offset/Shift for Reading-GB3RD). Press Menu to set the value.
- Scroll again until you see CTCSS/T-CTCSS/T-TONE. [T-CTCSS for Transmit-CTCSS which is not the same as R-CTCSS or Receive-CTCSS. For Repeaters we only want to use T-CTCSS.] Press Menu. Scroll until you see the correct CTCSS/T-CTCSS/T-TONE value (118.8 Hz for Reading-GB3RD). Press Menu to save the value.
- A push of the EXIT button or Transmit key takes you back to normal operation.
- When you push your Transmit key you’ll see the frequency on your display change to the transmit frequency (the Repeater’s input frequency) and the repeater should open and communicate.
- Don’t forget to identify yourself with your callsign when accessing the repeater.
Hopefully this will be of use to some of you as a refresher for the basics of using repeaters.
As ever, read your manual for your specific handset or mobile radio. Google and YouTube are also your friends when it comes to finding how-to information for your radio.
Basingstoke Repeater Details
- Callsign: GB3BA
- Band: 70CMs
- Output: 433.325 MHz [This is our listen-to frequency]
- Input: 438.325 MHz [This is our transmit-on frequency]
- Shift: +5.0 MHz
- T-CTCSS: 71.9 Hz
- Look here for more information on the Basingstoke GB3BA repeater.