New 70 MHz Repeater

07:53 Fernando Luiz de Souza 0 Comments

All Point Radio Island Link & Friends Of Our Link

We are pleased to announce that the Isle of Man (GD) will shortly be host to the very first UK narrow split repeater on 70 MHz (4m) call sign GB3AF.

Our island is a very strange place, and it has been almost impossible for amateurs in the north to talk to those in the south on 4m due to the mountain range in the centre of the island, hence our need for a repeater. Our chosen location is of course the tallest mountain on the island – Snaefell.

Standing at 2036 feet above sea level, and with fantastic take off in all directions, the repeater output power will be limited to 20 watts – more than enough to have a rag chew all over the island, and probably much further afield.

Input will be on 70.025 MHz, with a CTCSS tone of 110.9 Hz the “very narrow split” is 500 Hz making it accessible for the many elusive island amateurs and those around the Irish Sea basin.
The cavity filter has been specially manufactured from a pair of locally sourced Okell’s Brewery aluminium kegs, and some very detailed and extensive evening analysis by the team was required in order to prepare the barrels for use.

Our duplexer has been specially sourced from a manufacturer in China, who luckily for us was selling on eBay. We managed to sneak this item in below the Customs barrier marked as a “Toy”, again saving us some money which has been spent on a 50m reel of RG58, some PL259’s, and a roll of insulation tape (eBay special).

The antenna we have sourced is a 4m collinear, with a gain quoted by the manufacturer of 12dBi. The signal pattern for the antenna shows a very good all over island coverage, and signals should be wall to wall (good enough to blow some peoples windows out!) on both the west coast of UK, south of Scotland and the east coast of Ireland. It is uncertain as to how coverage will extend towards Wales as it was very misty the last time we ventured up Snaefell and we couldn’t see as far as Anglesey.

We are currently in the process of re-writing the repeater control logic to allow it to connect to the internet via Echolink and Allstar, again opening up more opportunity for people around the world to log in and use 4m. We again hope that we can somehow cross band this with GB3IM and GB3GD to further enhance the possibilities for multiple communication paths, and enable repeater pileups.

We hope that the repeater will be as popular as GB3GD is on 2m, and that amateurs worldwide take the opportunity to work those rare GD calls through the new internet linked system.

We have created a group for the management of the new repeater, together with a sub group for those who want to be a “Friend Of Our Link”. Any FOOL should make a suggested donation of £10 to support our future efforts:

All Point Radio Island Link – (Friends Of Our Link)
PO Box 110.9
Snaefell Mountain
Isle of Man
Dave Cain, 2D0YLX

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