147.390 WA4CHZ Repeater - Locust NC
The callsign belongs to Benton Blalock of Cottonville NC (close to Norwood). His call has been on the repeater
for over 20 years and even though W4DEX and myself have taken on the responsibility of maintaining the
system, we still consider this Benton's repeater.
Topographic map of Locust/Stanfield site at around 728 feet AMSL
WELCOME to the 147.390 WA4CHZ repeater located approximately 27 miles due east of Charlotte NC.
The repeater has been moved to a new tower (February 2004) and has an increased antenna height for
better coverage, especially to the north and north-west. The GE Mastr II repeater replaced the old Mastr Exec II
converted mobile which was running about 15 watts out of the duplexer. We are now running around 75 watts and receiving
around 6 dB better thanks to a Telewave TPRD-1556 six cavity duplexer with enough selectivity which allowed the
receiver to run with a GaAsFET preamp. Those who were once weak into the repeater are now making it just fine.
Repeater Facts
PL tone: 100.0 Hz used when necessary (usually all the time)
Equipment: GE Mastr II complete 110 watt repeater/base station
Antenna: Hustler G7-144
Antenna Height: 160 feet above ground or 880 feet AMSL
Feedline: Cablewave 1/2 inch (like Heliax)
Controller: IDA control board, factory controller for this repeater
Duplexer: Telewave TPRD-1556 six cavity BP-BR 2.0 dB insertion loss
Pramp: Mirage GaAsFET
Isolator: RJ Communications 152HP
CW ID board: Comm-Spec ID-8
Repeater TX power out of duplexer: ~ 75 watts
Receive Sensitivity: 0.30 microvolts for 20 dB SINAD (full quieting) through duplexer. No desense from TX
Lightning Protection: Polyphaser N-type bulkheads mounted on copper ground buss bar common with
AC power primary, tower ground, telephone line ground, and building ground. MOV protection on AC line.
Interesting Terminology - MASTR - an acronym used by GE means Mobile And Station Transistorized
Radio
THE REPEATER is a 1993 model GE Mastr II with a controller made by IDA. Pictured above are the main
components. The power supply is a split voltage with the station itself running on 12 volts and the power amp
running on 24 volts. The isolator is attached to the output of the power amplifier. Its purpose is to prevent
intermod, or the mixing of other strong signals at the site in the repeater's power amp. Loss through the isolator
is hardly even measurable (about 0.3 dB)
Pictured above is the main RF deck
Back side of repeater.
THE DUPLEXER is a Telewave TPRD-1556 which came with the surplused repeater. Six cavities were required to achieve high
isolation between the transmitter and receiver. Surprisingly, there's only about 1.8 dB of loss through each section.
We run about 90 watts out of the amp, and get 75 out of the duplexer.
THE ANTENNAS are located at the tower top which is 160 feet above ground.
This pic was taken before we changed the dual band out with a Hustler G7-144.
The "radio corner" of the building which contains repeaters for business band, public safety, county government microwave
and the ham repeaters. There are 11 transmitters at this site (including link transceivers for other repeaters) which
means sharp passband filtering and isolators on all transmitters are a must.
