MARS operates several repeater systems, including a VHF simulcast system. Check the Repeaters page for the latest information.
What is a voice repeater? A voice repeater is an automatically controlled amateur station that facilitates voice communications between other amateur stations, that are separated by distance or terrain. Repeaters do this by receiving incoming signals on one frequency and re-transmitting audio from the received signals on a different frequency. Repeaters do this by using special filters to separate the received and transmitted signals, called duplexers. Repeaters are usually installed where they have wide receive coverage areas. Repeater users listen on the repeater output frequency, and transmit to repeater’s input frequency. Most repeaters require a sub-audible access tone (CTCSS) to transmitted on the input frequency, to re-transmit a signal from a user.
What is a simulcast system? Simulcast is the simultaneous operation of two or more transmitters with overlapping coverage on the same frequency. This means that several repeaters operating on the same frequency are deployed to cover the area required. In our world that would be north, south and west portions of Marin County. By combining three repeaters into one system, Big Rock, Mt Tam and Mt Barnabe, we will dramatically improve our coverage area. In our system, we have different access tones (CTCSS) for each repeater in the system, but all transmitters are linked, so any received signal by one of the repeaters, is retransmitted by all three.
What is a digipeater? A digipeater is a store-and-forward device used in APRS and Packet modes.
A digipeater receives and stores data packets, and after a short period re-transmits the information, on the same frequency.
Updated 2025-07-21 WA6UDS
