N.A.R.C. Repeaters

2-Meter Repeater
145.270 Output / 144.670 Input; PL 162.2 Hz

The flagship of the Nixa Amateur Radio Club. The 145.270 repeater utilizes a Motorola Micor unified chassis that acts as the "guts" of the repeater. The repeater, born in 1976, was transformed from a Public Safety tone remote base station to a bona fide repeater by Repeater Builder in 2003. The 500 mW exciter drives the continuous duty Micor PA to 123-Watts output into the duplexers, a set of 4-cavity DB-4060's. On the receive side, we also use the Micor receive board in tandem with the original audio and squelch boards. In addition, the original helical pre-amp was tuned to 144.670 MHz and gives us one of the hottest and most selective VHF receivers around. Squelch opens at 0.11 uV with 12 dB SINAD at about 0.15 uV and 20 dB SINAD at 0.25 uV. These measurements include the loss incurred going through the Polyphaser, patch cabling, and duplexers. The repeater itself does not rely on commercial power. It is powered by a huge Panasonic 28-volt battery bank provided by Verizon. A Samlex, 50a continuous duty 28vdc to 12vdc converter is used power the entire repeater system. The Motorola Micor repeater was equipped with a regulated 9.6vdc, 1.5a power supply to provide the necessary 9.6vdc to the repeater. The repeater and battery bank are located inside a sturdy concrete, climate controlled building. Cellular carrier Verizon, who also has a site located on the water tower, provides the bank of batteries and building.

Everyone knows a repeater is only as good as its coax and antenna system, so those areas were considered of the utmost importance. The antenna is located atop the City of Nixa water tower at 911 W. Mt. Vernon Street in Nixa. The antenna, an Andrew DB-224 top-mounted in omni-directional configuration, is mounted at the 160' mark with the tip at 184'. Ground elevation at the base of the water tower is 1299 feet AMSL, with the tip of the antenna at 1483 feet AMSL. The antenna's six dBd of gain is preserved and sent down to the repeater with LDF6-50 1-1/4" Heliax. Considering system losses and gains, the repeater has an ERP of approximately 350-Watts.

The brain of the repeater is an SCOM 7330 3-port controller The controller does everything from handling both transmit and receive audio in the repeater, audio through the 442.425/447.425 link radio, controlling the cooling fans on the PA, to handling repeater and link radio traffic routing.

Speaking of linking, the repeater utilizes a CDM1550 low-power UHF link radio that can be used to link all the N.A.R.C. repeaters together via the Nixa ARC linking repeater, the 442.425 repeater located atop Cox South Hospital. The link radio utilizes a 25' run of RG-213 coax to an Andrew DB-436C yagi mounted on the ice bridge and pointed toward the "hub" of the linking system, the 442.425 repeater site. The link is of course protected with a coaxial Polyphaser.

Transmit Frequency: 145.270

Receive Frequency: 144.670

Tone: 162.2 Hz

Repeater: Motorola Micor with Unified Chassis

Controller: SCOM 7330 3-Port controller

Duplexers: DB-4060

Power: 95 Watts

Antenna: DB-224

Height: 184 Feet

Coax: Andrew 1-1/4" LDF6-50 Heliax

Above is a picture of the 145.270 site after the re-build in June 2010 with repeater mounted in the new 8' tall APC cabinet. Kolton Adkins, son of James Adkins, KB0NHX, admires the work. The Motorola Micor PA is at the top, followed by a 1U fan tray with 3 fans to keep the PA cool. The Micor unified chassis follows. Below is a 2u shelf with the 442.275 linking radio that is part of the Nixa ARC UHF repeater linking network, and the iLinkboards ULI EchoLink interface. Below is the SCOM 7330 controller, with the Nixa ARC FC-2 (fan control unit) built into a 1u rack mount cabinet. Below is a Duracomm 12vdc power distribution panel. Below is a 3U shelf which holds the Samlex SDC-60 27vdc to 12vdc 60a continuous duty DC converter that takes the power from the Verizon battery bank makes it a usable 12vdc to power the entire repeater system. Below is a KVM which is attached to the below Compaq ProLiant server, used as our local EchoLink node with wireless Internet on site, provided by Total Wireless. The DB Products DB-4060 duplexers take up the remainder of the cabinet

Pictured above is the Nixa ARC backup repeaters for the 145.270 site. This cabinet is two Motorola MSR-2000 repeaters with a single PA. The top MSR-2000 is wired up to plug directly into the SCOM 7330 controller should the Motorola Micor repeater fail. If we lose both the SCOM 7330 and the Motorola Micor, the bottom MSR-2000 is set up to run on the internal Motorola controller cards. This system is kept completely unplugged and in a separate cabinet so it is 100% isolated from lightening and ready to go should the 145.270 system fail.

6-Meter Repeater

The 53.270 is the second repeater that was put on the air by the Nixa Amateur Radio Club and is the only 6-meter on the air in Southwest Missouri. The total package for this single site repeater had a price tag near $40,000! Without numerous corporate cash and equipment donations, along with hard-nosed fundraising from the wonderful members of the club, this repeater would not be a reality. (see the Donor Recognition and the Member & Friend Recognition pages elsewhere on this site)

The 53.270 repeater is a wide coverage repeater. The guts of the repeater is a pair of Motorola CDM750 radios modified for the ham band. Each radio can be used as the transmitter or receiver in the system by simply changing channels. In addition, the repeater has a "backup" pair of CDM750's located and installed on site that can be utilized to make a total of four possible transmit and four possible receive radios. The transmit radio, set for 38-Watts output, drives a specially tuned Henry C300C30R amplifier to 242-Watts output into a set of TX RX Systems Vari-Notch 28-25-92358 4-cavity duplexers. From there, the signal goes through 25' of FSJ4-50B 1/2" superflex to the Polyphaser lightening protection. Transmit ERP is a whopping 740-Watts. On the receive side, signals are first run through the duplexers, then fed into an AR2 P50VD pre-amp with 15dB of gain, then fed into the TX RX Systems 11-14-06 dual-cavity bandpass filters before making its way to the receiver. The exciter and receive radios, along with the controller and link radio receive their power from an Astron RM-60M. In case of failure, a second Astron RM-60M is rack mounted and ready to run the system at the flip of a switch. The amplifier uses the internal 28 vdc Samlex power supply provided by Henry Radio. The repeater also has backup power in place. The site's UPS will hold power until the Onan power plant, powered by a Ford 460 V10 Turbo charged LP engine, is ready to go. The repeater itself, along with backup power, is located inside a ruggedized concrete building provided by the Springfield / Greene County Trunked Radio System Board.

Location, Location, Location....and antenna system and feedline are the three things that make an awesome repeater system really come together. The repeater antenna system is located on a 600' guyed tower, with the topmost bay at the 500' mark. The tower itself is at 1253' AMSL with the tip of the antenna at 1753' AMSL. The antenna system, a 6.6 dBd gain Andrew DB-212-C-6, spans almost 90' of vertical real estate as it winds down the tower providing an omni-directional radiation pattern. The 6-meter antenna is fed with 450' of Andrew LDF6-50 1-1/4" heliax, which only grosses about 1 dB of loss up the tower. In addition to the 6-meter antenna, a 6.6 dBd gain Andrew DB-408A is mounted at the 400' mark to be utilized to receive RF from the 5 planned remote receivers. The antenna is fed with 406' of Andrew LDF5-50 7/8" heliax to the entry of the building where a Polyphaser protects the UHF radio from lightening. A short 25' of FSJ4-50B 1/2" superflex takes the signal to a DBSpectra 8-port UHF receive multi-coupler.

The brain of the repeater is a Computer Automation Technology CAT-1000B controller with an RLS-1000B remote link port switch. The controller handles all the repeater and link radio audio and can be set to operate in "normal traffic", "weather net", "weekly net", or "emergency traffic net" modes. Each "personality" has different features enabled or disabled to best suit the situation at hand.

The repeater can be linked into the Nixa Amateur Radio Club's 442.425 linking repeater allowing it to be linked to any other repeater in the NARC network. A low-power Motorola CDM1550 is connected to a DB-436 yagi which is pointed toward Cox South Hospital, the home of the 442.425 repeater. They yagi, at the 50' mark, is fed with 75' of Andrew FSJ4-50B 1/2" superflex with Polyphaser lightening protection.

This repeater can reliably be accessed by 100-Watt mobiles with a loaded 1/4 wave as far away as Joplin, Lamar, El Dorado Springs, Osceola, Buffalo, Lebanon, Mountain Grove, Omaha, AR, Berryville, AR and Neosho, MO. Base stations in the Kansas City, MO area are able to utilize the machine with 100-Watts and simple 3-element beam at the 50' mark.

Transmit Frequency: 53.270

Receive Frequency: 51.570

Tone: 162.2 Hz

Repeater: Motorola CDM-750 radios

Controller: CAT-1000B & CAT RLS-1000B Remote Link Switch

Duplexers: TX RX Systems Vari-Notch 28-25-92358

Bandpass Filter: TX RX Systems 11-14-06

Power: 242 Watts

Antenna: Andrew DB212-C-6 Antenna (6 bays total)

Height: Topmost bay is installed at 500 Feet AGL

Coax: Andrew 1-1/4" LDF6-50 Heliax

Above is another picture of the 53.270 MHz repeater. You can see the redundant Astron RM-60M power supplies and redundant exciter & receive Motorola CDM-750 radios all ready to go at a moment's notice. Below the CAT-1000B controller and RLS-1000 Remote Link Switch, you can see the dBSpectra 8-port RX multi-coupler to be used to split our UHF remote receiver antenna to up to 8 remote receive CDM-1250 radios. Below, you see the 442.425 / 447.425 linking radio that is part of the Nixa ARC UHF repeater linking network that allows us to link all repeaters together. Not pictured are recent additions to the repeater. A Microtik router routes Internet traffic, and a JPS NXU-2A is used for IP based communications to / from the repeater site by served agencies when needed

70-Centimeter Repeater

442.150 Output / 447.150 Input; PL 162.2 Hz

The 442.150 Repeater was put into operation on Tuesday, July 3, 2012 by members of the Nixa Amateur Radio Club, Inc. (K0NXA). The Andrew DB-420 repeater antenna is mounted 200' AGL / 1505' AMSL atop a City of Crane water tower. The antenna is fed with Andrew LDF5-50 7/8" heliax with a Polyphaser installed at the coax entry panel and a 20' jumper of Andrew FSJ4-50B 1/2" superflex to connect to the TX RX 28-66-02A duplexers.

The repeater is a Motorola Micor Unified Chassis repeater, modified to the ham band by James Adkins, KB0NHX. The repeater utilizes a CommSpec TS-64DS tone decode board to send PL logic and filtered receive audio to the SCOM 7330 controller. The repeater utilizes a single TX RX pass / notch bandpass filter to notch out all frequencies between 450-465 MHz and an AR2 receive pre-amp to enhance receive sensitivity. We built our standard FC-2 Fan Control unit to control the fan for the IRLP / Phase II UHF link radio.

The repeater is the "hub" linking repeater for the new Southwest Missouri linked repeater system, which includes the following repeaters: 147.015 + in Springfield, the 145.390 - in Granby, the 145.450 - in Nevada, and the 444.975 + at Stockton Lake.

The repeater uses a Motorola CDM-1250 UHF radio connected to an Andrew DB-436A antenna at the 175'AGL mark fed with LDF5-50 7/8" heliax. The radio provides a reliable RF link to the system IRLP node 7191.

The repeater will be linked into the club's repeater linking network from 7:00 p.m. to 9:00 p.m. on Thursday evenings as well and will allow operators to check into the Thursday night Nixa ARC net at 7:30 p.m. from this repeater as well so they can explore and test the link repeater system via the repeater's IRLP node, node number 7191

Transmit Frequency: 442.150

Receive Frequency: 447.150

Tone: 162.2 Hz

Repeater: Motorola Micor Unified Chassis

Controller: SCOM 7330

Duplexers: TX RX 28-66-02A

Power: 80 Watts

Antenna: Andrew DB-420

Height: 200 Feet

Coax: Andrew LDF5-50 7/8" heliax

70-Centimeter Repeater

442.425 Output / 447.425 Input; PL 162.2 Hz

The 442.425 repeater is the third repeater put on the air by the Nixa Amateur Radio Club, Inc. This repeater is meant for "local coverage" for the Nixa, Ozark and Springfield area with an emphasis on handheld coverage in those areas.

The repeater itself is a pair of Motorola CDM750 radios, powered by an Iota DLS-75 75a continuous duty power supply. The transmitter feeds 20-Watts into the Henry 200w amplifier, which then travels to the TX RX 28-66-02A 4-cavity duplexers. All losses totaled, the repeater transmits 142w out of the duplexers. A 10' Andrew FSJ4-50B patch cable feeds the Polyphaser lightening arrestor, with a whopping 30' run of Andrew AVA7-50 Coax to the 6.6 dB Andrew DB-408B omni-directional antenna. The repeater shares an SCOM 7330 controller with the 224.280 and IRLP node located in the same equipment room. The 442.425 acts as the "hub," or "linking repeater," for the Nixa Amateur Radio Club NARC Network. It can link any two repeaters, or all repeaters simultaneously. In linking repeater mode, the courtesy tone is removed, and the hang time reduced to zero. In addition, the PL tone is stripped from the CW ID so it is not broadcast across the link.

IRLP node #3995 is connected to the 442.425 repeater full-time and is available for use by any licensed amateur. The repeater is normally connected to Reflector 9330 and is part of the Central Region Intertie System, visit www.centralregionintertie.info.

The repeater is located atop Cox South Hospital at the intersection of US Hwy 60 and National Avenue and inside the hospital's equipment shed. Ground level for the hospital 1315' AMSL with the antenna tip at 148' above ground level, placing it at 1463' AMSL. Typical coverage for 35-Watt mobiles is 30 to 40 miles from the repeater site.

Transmit Frequency: 442.425

Receive Frequency: 447.425

Tone: 162.2 Hz

Repeater: Motorola CDM750 radios

Controller: SCOM 7330

Duplexers: TX RX 28-66-02A

Amplifier: Henry 200w Amplifier

Power: 142-Watts

Antenna: Andrew DB-408B

Height: 152 Feet

Coax: Andrew 7/8" LDF5-50 Heliax

Picture of the Cox South Repeater site, which includes the 224.280 Repeater at the top of the rack, then the SCOM 7330 controller, followed by the 442.425 Repeater equipment, and the IRLP PC, remote control PC & Linksys router, and APC BackUPS 1000 Pro UPS

1.25-Meter Repeater

224.280 Output / 222.680 Input; PL 162.2 Hz

From high atop the penthouse at Cox South Hospital in Springfield, MO, the 224.280 repeater hails. The repeater was first approved by members of the Nixa ARC in December 2005. The fourth repeater put on the air by the Nixa ARC, the 224.280 repeater utilizes a pair of specially modified Motorola CDM1550LS+ radios.

The 3-Watt exciter is fed into the Henry C200B10R 200-W amplifier and then continues to the TX RX 28-52-02A 4-cavity duplexers for 138-W out to the antenna. From the duplexers, 15 feet of Andrew FSJ4-50B ½" Superflex takes the signal to the Polyphaser lightening arrestor. From there, 10' of Andrew AVA5-50 7/8" heliax takes the signal to the Andrew DB573-EE 3 dB gain 220 MHz omni-directional repeater antenna. The super-hot receiver only needs 0.20 uV to open squelch, with a 0.26 uV signal providing a 20 dB SINAD signal, this includes losses through the TX RX duplexer and the 4-cavivity Sinclair bandpass filter!

The repeater shares its SCOM 7330 controller with the 442.425 repeater also located at Cox South. The controller allows both repeaters to operate independently or be linked together whenever needed.

Cox South Hospital in Springfield, MO is located near US 60 and National Avenue and has a ground level AMSL of 1315', with the tip of the antenna located approximately 152' above ground at 1467' AMSL. You can expect to work the repeater from 35 to 40 miles out with a 25-Watt mobile and 3 dB gain antenna.

Transmit Frequency: 224.280

Receive Frequency: 222.680

Tone: 162.2 Hz

Repeater: Motorola CDM1550LS+

Controller: SCOM 7330

Duplexers: TX RX 28-52-02A (4-cavities)

Power: 138 Watts

Antenna: Andrew DB-573-EE

Height: 152 Feet

Coax: Andrew 7/8" AVA5-50 Heliax

2-Meter Repeater

147.015 Output / 147.615 Input; PL 162.2 Hz

This is the 6th repeater put into operation by the Nixa ARC in October 2012.

The repeater is an ultra reliable Daniel's Electronics MT-2 with a 300-W Crescend PA, running at 225-Watts and utilizes an SCOM 7330 controller with TX RX 28-37-02A duplexers.

On the tower, 400' of Andrew AVA7-50 1-5/8" heliax, with loss characteristics of 2-1/4" foam heliax, was installed to minimize losses and an Andrew DB224-E 6 dBd gain antenna mounted at 400' AGL on the West leg to maximize coverage in the Springfield metro area and to the West. An Andrew DB-5004 side mount will be used to mount the antenna to the tower, and an Andrew DB5004S-MTD sway brace at the top of the antenna for extra support.

The repeater is linked into the SMLRS (Southwest Missouri Linked Repeater System, visit www.smlrs.info) full time via the 442.150 Crane hub repeater. During Thursday nights, this repeater, and all on the SMLRS, are linked into the Nixa ARC multi-band linked repeater network. The repeater utilizes and Andrew DB-436C at 50' AGL and fed with Andrew LDF4-50 1/2" heliax with a Polyphaser for lightening protection. A commercial Motorola CDM1250 link radio is used to link to the 442.150 Crane repeater. One of the NARC FC-2 Fan Control units were constructed to control fans for all transmitters on site. A Duracomm 75A DC Distribution panel tidies up the site DC power cabling and provides power breakout for all devices. A Microtik router on site distributes Internet provided by TA Highspeed for the sites JPS NXU-2A IP linking device, used to help served agencies have IP based connectivity into the network.

Transmit Frequency: 147.015

Receive Frequency: 147.615

Tone: 162.2 Hz

Repeater: Daniel's MT-2 with Crescend 300W PA

Controller: SCOM 7330

Duplexers: TX RX 28-37-02A

Power: 175-Watts

Antenna: Andrew DB224-E

Height: 400 Feet, mounted on West leg of tower

Coax: Andrew AVA7-50 1-5/8" Virtual Air heliax