N6ICW System Equipment
.......... .RF equipment for this system is all Motorola radios for the 147.195 system. With the system being a split site design most of the repeater is piecemeal, except for the Tahoe 145.150 and the Chico 146.940 repeaters which are a Kenwood TKR-750 25 watt repeaters.
.......... All voting receivers are Motorola Micor, which have audio/cos board using Motorola Micor "smart squelch" IC and audio shaping. The UHF down link transmitters are Motorola MSR2000 1/2 watt exciters or Motorola Mitrek 10 watt transmitter. Each receiver is using an omni directional antenna fed with hardline, bandpass cavities, and preamp (if site noise permits its use). Five of the receiver sites use community receive antennas with between 2 to 12 receivers on an antenna. The down link transmitters use 1/2" hardline to a 6 element yagi for point to point communication.
.......... The hub of the system is in North Sacramento with a dedicated 35' Rohn 25 tower used for the up and down link antennas. On the main commercial tower at 300' is a Super Stationmaster antenna for the back up Motorola 350 watt paging transmitter. There is 350' of 1/2" hardline to feed this antenna (I guess this hardline won't ice up).
........ The main cabinet has 8 chassis for Motorola Micor UHF receivers feeding two Hall voting cards. Each UHF receiver is on a dedicated 6 element yagi for point to point links and has a bandpass cavity for protection. These receivers also decode the system PL off of each voting receiver then audio is routed thru a Selectone PL notch filter. Audio output from the Hall voter is then passed thru a 1/3 octave graphic equalizer, that output then goes to the ACC RC-96 and Link Com RLC-3 controller. Digital audio delay is looped from the controller to an external delay line. Controller output is then passed again thru another channel of the graphic equalizer then to the Motorola Maxtrac 902 MHz up link transmitter. This link uses a Scala corner reflector antenna aimed at Mt. Vaca.
.......... The system also
has a steerable Icom remote base for 2 meters, 220 MHz, and 440 MHz.
Link antennas are on the commercial tower between 125 to 200 feet.
There is also a
UHF control receiver.
......... The Mt. Vaca 147.195 transmit site is a VHF Motorola PURC 5000 simulcast transmitter with a Micor 902 MHz link receiver. This receiver uses a Scala corner reflector antenna, and bandpass cavity. This package uses a Link Com RLC-1 controller. The VHF transmitter has an external circulator and harmonic filter then feeds a 10" bandpass cavity. The VHF antennas are 4 Telewave Folded Dipoles with a 9 db pattern, fed with 60' 7/8" hardline. All sites have either generator or battery back up except the Mt. Vaca transmitter. The controllers have separate battery back up to maintain their current configuration.
....... .......... The Tahoe
repeater is a Kenwood TKR-750 with an Link RLC1 controller. This site
uses a master receive antenna for the repeater and the 147.195 link
receiver and a receiver for another VHF repeater. The transmitters of
both systems combine into a common transmit antenna. The link
transmitter has a separate yagi aimed to the west.
...... .......... The Chico repeater is a Kenwood TKR-750 with an Link RLC1 controller. This site uses a master receive antenna for the repeater and the 147.195 link receiver. The transmitter antenna is a 2 Telwave Folded Dipoles with a 6 db pattern. The link transmitter has a separate yagi aimed to the south.
Please refer to the block diagram for the system configuration.
© 2012 Chris Huber, All Rights Reserved.