THE TRANSMISSION GALLERY
|Photos by Jack Richardson||Page last updated: 2021-08-21|
|Stopped here on the way back from Gairloch/Melvaig. Lying beside the A832 at the Glen Docherty pass summit, there’s a track from the road to the site, as well as a footpath.|
Glen Docherty was one of a number of link sites bringing TV and radio to North West Scotland. The site was originally built by the BBC to provide a feed of 405-line BBC 1 to Melvaig by direct reception of the channel 2 transmissions from Rosemarkie and then via an SHF link. In the mid 1970's this was all re-engineered to provide four channels of 625-line colour TV and in the late 1980's the BBC PCM/Nicam radio distribution.
The feed started at Rosemarkie, onto Glenmarksie, Falls of Conon, Sgurr Marcasaidh, Glen Docherty, Melvaig and onto Eitshal and Skriaig. To save on the cost of putting in electricity, access road, maintenance etc in this remote and mountainous area, Sgurr Marcasaidh and Glenmarksie were passive repeaters. Sgurr Marcasaidh had 2 dishes mounted back-to-back, connected with no powered electronics, while Glenmarksie had two parallel plates mounted around 180 degrees from each other. Falls of Conon was an active repeater, adjacent to a road and an electricity substation with dishes pointing towards Glenmarksie and Sgurr Marcasaidh. More information about the link system is provided in a BBC Engineering article.
On 17th January 1983 one of the dishes at Sgurr Marcasaidh was blown off in a gale. Service was restored around 3 weeks later, on February 9th, in arduous conditions including deep snow, freezing temperatures and light wind. This is detailed in a BBC Engineering article from the time.
I think you would be able to Rx Rosemarkie direct here, it was chucking in a good signal on my car radio. However, it seems there was a desire to provide bespoke programming to Eitshal, and possible interference from planned Norwegian TV stations meant an SHF link system was needed.
I'd imagine the feeds to Melvaig/Eitshal/Skriaig are all fibre nowadays, but Glen Docherty appears to be in full use by Arqiva, and well looked after.
|The site is in a wooded area|
|The dish at the top of the tower points north west towards Melvaig 28 miles away.|
The dish at the bottom points eastwards towards Sgurr Marcasaidh about 17 miles away.
|The view as seen by the dish towards Sgurr Marcasaidh|
Eitshal | Melvaig | Rosemarkie | Skriaig
BBC Engineering: The SHF Link System from Rosemarkie to Eitshal (Page 30 onwards)
Sgurr Marcasaidh dish blown over (Page 9)
Falls of Conon (Google maps)
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