70cm UHF Repeater

GB3OV

Serving the River Great Ouse valley across Cambridgeshire & Bedfordshire. Sited near Graveley at approximately 40 metres above mean sea level.

Output: 433.225 MHz Input: 434.825 MHz (-1.6 MHz) CTCSS: 67.0 Hz (Tone A) Keeper 1990–2010

Historical Archive Notice (Pre-2010 Record)

Please Note: I was the licence holder and keeper of repeater GB3OV between 1990 and 2010. In 2010, I moved down to the south coast and have had no further involvement in the repeater since that time.

The control logic, coverage maps, and technical specifications documented on this page represent the repeater as it was configured and operated under my stewardship prior to 2010. They may not reflect the current repeater, its modern hardware, or current operating parameters. For current operational details, please consult the Huntingdonshire Amateur Radio Society (HARS) ↗ or the UK Repeater Management Group.

History & Operation

I was the licence holder and keeper of repeater GB3OV for 20 years between 1990 and 2010, before moving down to the south coast. Since 2010, I have had no involvement with the ongoing running or maintenance of the repeater.

The repeater originally entered service on 24 November 1985. It was administered and supported by the Huntingdonshire Amateur Radio Society (HARS) ↗.

GB3OV was conceived primarily to provide reliable coverage across the four Great Ouse valley towns: Huntingdon, Godmanchester, St. Ives, and St. Neots (hence the callsign suffix OV for Ouse Valley).

In addition to local valley coverage, the site provided solid communication corridors:

North along the A1 to Peterborough
South along the A1 to Sandy
East along the A14 to Cambridge
West along the A14 to Thrapston

Custom PIC Control Logic

I designed and constructed a custom PIC microcontroller-based control logic for GB3OV. The firmware managed:

Precision Morse ident generation ("GB3OV") at scheduled intervals
Carrier-operated squelch (COS) and timeout anti-babble protection
Continuous CTCSS tone decoding (67 Hz Tone A) and 1750 Hz toneburst detection
Telemetry beacons, beacon muting, and automated diagnostic status indicators

Engineered for high reliability, this microcontroller control system survived faithfully in continuous 24/7 service without failure across all those years.

Technical Specifications (Historical Configuration Prior to 2010)

The parameters below represent the repeater during my tenure as keeper up to 2010. They may not reflect the current repeater.

Parameter	Specification (Pre-2010)
Callsign	GB3OV
Band	70 cm (UHF)
Output Frequency (TX)	433.225 MHz
Input Frequency (RX)	434.825 MHz (-1.6 MHz split)
Access Requirements	67.0 Hz CTCSS (Tone A) or 1750 Hz Tone Burst
Hardware Platform	Tait 300 Series Base Station
Controller	Custom Microchip PIC Microcontroller Logic (Designed by Dave Massey)
Antenna	Single Collinear Antenna at the apex of a 10-metre mast
Site Elevation	Graveley, approx. 40 metres above mean sea level
Sponsoring Club	Huntingdonshire Amateur Radio Society (HARS)

Coverage Map (Historical Pre-2010 Model)

Estimated coverage plot for GB3OV across Cambridgeshire, Bedfordshire, and adjoining transport corridors as modeled prior to 2010:

Click map to enlarge in full-screen view