The latest upgrades to GB3KM..

GB3KM DTMF PC Control Pad

Here is the PC DTMF control program for GB3KM - Updated with adjustable tone delay Feb 2010

If you have the previous version installed then please uninstall it first before installing this version.

Sequencer board

This is yet another board for GB3KM. it's purpose it to further simplify the repeater and make it a little more future proof when we make updates. It basically takes control of the startup and shutdown of the repeater as certain things needs to be powered up/down before others if there is a power failure etc..

Design is very similar to the logic board suing the same devices and relay outputs.

Logic Controller Board

This is the new logic controller board for GB3KM, Uses a PIC16F84 and is based on the simple logic controller designed by Jason, G7KPM for the GB3GG repeater, ours has has a few changes to the code to make it work for the current QUAD switching unit in KM.

It uses the Four sync detector inputs to decide whether to show a single input or if there is more than one station then switch to quad screen mode. Currently the logic in KM has capability for only 2 sync inputs. There is a new CW Ident built in without the 'N' every few seconds :-)

The K is now seen after using the repeater.

GB3KM on 10GHz

Antennas are Slotted waveguide from Micro-Mechanik

Rx filter is also from the same place, 10.315GHZ +/- 50MHz

Rx downconverter is a modified Maspro WG17 LNB for 9GHz LO

Transmitter is a Cambridge LNB modified for transmit on 10.065GHz ~30mW

Driver amp is G3WDG 250mW unit

Final amp is from commercial 'Whitebox' unit ~1W to antenna.

Transmitter baseband modulator for KM, very similar to a design from an article in CQ-TV some years ago..

Audio Squelch

This is the FM Sound Squelch board for the repeater. It removes the loud noise burst when a station switches off after accessing the repeater or if the station accessing is too weak with poor audio sub carrier.

It is based on the design from here with some modifications to mute the audio path from the squelch on/off output from the detector circuit. The mute is from a design on here using a 4016 Quad Analogue Switch.

Sync Detectors

4x sync detector for GB3KM, design by ZL1WTT

DTMF

DTMF Control board for GB3KM, design by GW6BWX