224.280

224.280 Repeater - Republic, MO

On-Air Date:                    March 2007

Repeater Transmit:         224.280

Repeater Receive:           222.680               (-1.600 kHz)

Modes:                               Analog

PL Tone:                             162.2 Hz

PL Direction:                      Encode & Decode

Bandwidth:                        Wideband – 25 kHz

Transmit Power:               100-Watts

Antenna System:              Comprod 872F-70-2-TM-1/4 – 315’ AGL

Link antennas:                   N/A

Coax Cable:                        Commscope LDF7-50 1-5/8" Heliax

Controller:                         SCOM 7330

Repeater                            Motorola CDM-1550LS+ for Exciter & Receiver

Amplifier                             100-W Securicor LMA30052

Duplexer:                            TX RX 28-52-02A

Link Radios:                       N/A

Backup power:                  Site Generator

Router:                               Ubiquiti Edgerouter X

Internet:                             Yes - Springnet

Nets:                                   Thursdays @ 7:30 p.m.  - Nixa ARC Check-in Net

                                           Wednesdays @ 8:00 p.m. – Combined Sedalia – Springfield 220 Net

The 224.280 repeater was the fourth repeater placed into service by the Nixa ARC.  Originally this repeater was located at Cox South Hospital in Springfield, MO with a callsign of KC0LUN.  In July 2011, the callsign was changed to K0NXA.  However, it was moved to the Christian County 911 tower in Clever, MO and went online May 6, 2017 to evade interference from the third harmonic of the Cox South Hospital time clock transmitter operating near 72 MHz.  In July 2023, the repeater was moved to the City Utilities tower in Repbulic, MO thanks to efforts made by Jeff Bertholdi, W0AV.  The timing was good as the Christian County 911 cancelled our 99 year lease after only 6 years to be effective in September 2023 because they needed the tower space for their proposed 700 MHz P25 trunked radio system antennas.

The original DB573-EE 217-222 MHz fiberglass antenna was removed from Cox South and replaced with the true 220-225 MHz Commscope DB224-JJ courtesy of a trade with Bob Buford, W5RAB-SK, in Bartlesville, OK.

The original repeater was a Motorola Micor converted to 220 MHz by Repeater Builder with a 25-Watt amplifier and an Arcom RC-210 controller.  Since the repeater was converted from VHF, it had a lot of problems with the 2500-W ERP VHF paging transmitter also on Cox South Hospital.  The repeater was sold and replaced with a pair of Motorola CDM-1550LS+ mobile radios thanks to a retired Motorola engineer sending us some "modified" S-records to program into the radio allowing the radios to work above 222 MHz.  The radios made a huge difference in the repeater receive while maintaining the 25-W output.  Soon, the club began looking at improving the range of the repeater and purchased a Henry C200B10R 200-W amplifier with Iota DLS-75 power supply.  The amplifier was extremely problematic and eventually sold and funds used to purchase a commercially made amplifier for the 220 MHz band.  Again, Bob Buford, W5RAB-SK, stepped in and clued us in on using a Securicor ACSB amplifier manufactured in the United Kingdom that they had been using in Oklahoma on their 220 repeaters - 10mW input would provide 100-W output.  This was exactly what we had been seeking! 

When the repeater was moved to Republic on July 1, 2023, a Comprod 872F-70-2-TM antenna had been purchased from Jim, W7RY for $500 when he abandoned his 223.940 repeater after only being online for a year in Nixa, was installed on the tower with a 6’ standoff at 325’ AGL.