Operation

The logic comprises of a custom PIC with software written by GD4HOZ.

For initial access it requires a 1750Hz toneburst of approx. 400msec duration and then the carrier continued for at least 3.5secs to latch the repeater into operation, or a 110.9Hz CTCSS sub audible tone (tone H) on the repeater input frequency of 145.075MHz.

The repeater output frequency is 145.675MHz (R3/RV54). After access the repeater will relay the FM signal for 215secs (4.25m), after which time if the transmission continues it will time out and close down. A pip tone follows dropping of the carrier where the TOT (Time Out Timer) is reset. A second pip follows, but is just for courtesy if stations want to allow extra time for other users calling in. Stations failing to wait for the first pip tone will only have what time was left by the previous station before handing over. Once the repeater is open access can be by carrier only.

The repeater identifies itself at high deviation every 5 minutes during quiet periods including an H suffix for the CTCSS frequency and at low deviation during busy periods. A longer ID with repeater location is given every 25mins when quiet.