The Richmond Amateur Telecommunications Society owns and operates two repeaters under the club’s callsign, W4RAT, on the SERA-coordinated frequency pairs of 146.28/88 MHz and 442.55/447.55 MHz. Both repeaters use full CTCSS encoding and decoding at 74.4Hz. The VHF IRLP node is 4424, the UHF is 4995.
The picture above shows the two repeater racks. Top to bottom are the IRLP servers (click here for more about the W4RAT IRLP nodes!), inline wattmeters, then the repeaters themselves (UHF on the left, VHF on the right), then the NOAA Weatheradio alert system, and then the controllers with digital voice recorders. The batteries for power backup are at the very bottom of the racks. The large black cabinet to the right is the VHF duplexer (you can just see it).
The 146.88 and 442.55 repeaters are co-located at WCVE Channel 23 in Chesterfield County (near Bon Air), with their antennas situated about 680 feet above ground on the taller of the station’s two large towers. In the photo below, the upper pair of antennas are the W4RAT antennas. The one on the left is the 2M (146MHz) antenna, the one on the right is the 70cm (442MHz)antenna. RATS appreciates WCVE’s generosity in allowing us such excellent locations for our antennas and repeaters.
Both stations consist of Motorola MTR 2000 repeaters, full featured controllers and Digital Voice Recorders, a Duplex Products duplexer for VHF, a Celwave Duplexer for UHF, a Decibel Products DB-224-E antenna on VHF (above, top left), an RF Systems antenna on UHF (above, top right), and 750 feet of 1-1/4-inch hard-line which feeds both antennas from an RX TX coupler.
Both repeaters are accessed by a CTCSS (PL) tone of 74.4Hz and transmit a 74.4Hz sub-audible tone, so you may set your receiver to break squelch only when the RATS repeaters are transmitting. You must transmit a 74.4Hz tone to bring the repeaters up! The tones are used to avoid interference from other repeaters whose coverage occasionally overlaps ours, and is suggested by the Southeastern Repeater Association, our frequency coordinating body in southern Virginia and the southeast. Each transmitter’s output power is approximately 70 watts.
If you have questions about the operation of the W4RAT repeaters, please e-mail the RATS Technical Committee.
This is the projected coverage map of the “88” repeater shown by the mapping program SERA uses.