GB3LD

The GB3LD 2m Voice repeater is located at the Langthwaite Farm transmitter site situated 2 miles SE of Lancaster. (QRA IO84OA, 470ft ASL.  East of the M6.)


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The antenna is located on the NW section of the mast @ 55ft AGL and is spaced 1/4 wave from the mast so as to give a maximum coverage lobe into the Lake District and West Cumbria.

Transmission line is by LDF5-50 heliax.

This serves a dual purpose as it also gives a null in the direction of the Barnsley repeater GB3NA, thereby keeping CO-channel interference to a minimum.

The current version of GB3LD (MkIII) uses a Nokia BSR-150L/N PMR repeater that was originally used in a public utilities communication system.

The earlier repeaters that use 2 Pye MX294's, (1 used as a transmitter, 1 as a receiver) have been retained as emergency spares with each one being self contained in their own case.

Output is approx. 12dBW/16W ERP via a Wacom WP641 duplexer and a J-Beam dipole type 7051. The receiver has a DCI-145-2H , 2 Mhz wide bandpass filter in the antenna feed to keep out local pager transmitters.

A three section AFL notch filter has been added to minimize interaction from a PMR VHF high band base station located at the same site.

Repeater control logic is by a custom built PIC circuit with GB3LD specific firmware written by GD4HOZ