GB7OK Technical Specifications
GB7OK D-Star Repeater


Frequency Output 145.7125 MHz, Input 145.1125 MHz
TX RX Split Minus 600 kHz Split (user's, split)
Location Chelsfield, Kent. (close to Junction 4 of the M25)
Locator JO01BI or NGR TQ497643
Station ID Morse GB7OK /C Port C "OK" for Orpington, Kent.
Mode of Operation Digital Voice "DV" (6.25 kHz)
Type of Emission F1D (GMSK); F7W with ID-RP2C
Power 25W ERP
Antenna Diamond X-300 Fixed Base Station Vertical 2x5/8 @ 6.5dB
Antenna Height AGL 9 Metres or 30 Feet above ground level
Base of Mast ASL 284 Metres or 600 Feet above sea level
Repeater Controller Icom RP2C controller
Duplexer Wacom 4 Bp/Bs commercial (Coming soon 5 AFL-140's)


The hardware is based on the next generation digital amateur radio system. The D-STAR system provides digitally modulated voice/data communication and high-speed data access over the air. This project has been developed in collaboration with JARL (Japan Amateur Radio League) and is supported by the Japanese Telecommunications Administration.

D-STAR incorporates the power of digital voice and 1kbps data mode on 2m, 70cm, and 23cm. The spectral efficiency, crystal clarity, and the ability of repeating data and voice communications on a single 6.25 kHz channel is something yet to be seen in any other radio service!

The Icom is supplied with an two s"N" Type connector for the transmitter and the receiver to allow easy connection to the diplexer or feeder cables. also includes rear panel a RJ45 connector that allow easy connection to external controller. All housed within one 4RU equipment cabinet.


Transmit Frequency Output 145.7125 MHz
RF Power Output 23-30W (high)/2-3W (low) (Continuous Duty Cycle)
Frequency Deviation Narrow-band + or - 2.4KHz
Oscillation System Direct PLL (Phase Locked Loop) Synthesizer System
Transmission Speed 4.8 kbps (Voice 2400 bps, FEC 1200 bps, data 952 bps)
Frequency Stability Within ±0.3 kHz (at 25?C; +77?F)
Frequency Response 5/6.25 kHz
Spurious Emissions Less than -60 dB


Receive Frequency Input 145.1125 MHz
1st IF 46.35 MHz
2nd IF 450 kHz
D-Star Repeater Controller

RP2C D-Star Repeater Controller

Icom RP2C controller. D-Star repeater modules communicate digitally with the RP2000V VHF Repeater Base Station also the RP2C can control up to four repeater modules This includes basic in-band as well as crossband operation between any of the four digital voice RF modules. In addition to basic control of the RF modules along with two microwave linking modules.

The RP2C is a digital unit only, there are NO ANALOG INTERFACES provided. You cannot hook up your analog controller, forget about plugging in an Echolink or IRLP interface.

RMC Computer Generated Predicted Coverage
GB7OK Coverage Map
Colour Key   RMC Computer Generated Predicted Coverage
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