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THE TRANSMISSION GALLERY
BEACON HILL A
| Photos by Jim Fraser | Page last updated: 2016-11-17 |
| Dear Diary, August 2007 was the start of antenna changes on the Beacon Hill mast. The analogue TV signals were switched from the cylinder antenna at the very top of the mast to the reserve panel array antenna just below (but still above the digital panel array). |
| The analogue power from the reserve antenna was reduced frequently from August through to November whilst riggers were working on the mast. In October 2007, the old analogue cylinder antenna was removed using a special crane attached to the top platform. The new antenna (four-sided panel array) was laid out on the ground ready for the swap. |
| November 2007 had the new top antenna in place, with riggers still working on the mast. |
| Towards the end of December 2007, the analogue signals were switched to the new top antenna, with the digital signals remaining on the bottom panel array. Instances of adjacent channel interference spoiling digital reception were then noticed in some areas which previously had good reception. In January 2008 the reserve antenna was removed (I’ve no idea why) – all of a sudden it wasn’t there – presumably it didn’t have the correct radiation pattern. |
| Towards the end of Feb 2008, the new reserve antenna was installed – which looked much more like the digital panel antenna. |
| In March 2008, riggers were still working up the mast. The photos show them working above the reserve antenna, possibly on the feeder connections. |
| At the beginning of April, riggers were spotted on the mast, with half of the (new) reserve antenna being lowered to the ground. The other half was removed similarly. |
| After a couple of weeks, half of the reserve antenna was seen to have been replaced, with the second half appearing later on the same day. The photo shows a slight gap remaining between the two sections, waiting to be closed fully. |
| Just when we thought the changes might have ended, riggers were again spotted at the top of the mast at the end of May 2008, removing all the panels from the (new) top antenna, leaving just the lattice support framework with the feeder cables visible inside. The rumour was that the antenna had been positioned 90° out from its intended mounting (implying that it has a non-symmetrical HRP) and it needed “turning”. There was also a suggestion that parts of the feeder may not have been performing as expected. This also indicated that the analogue TV signals had been switched to the reserve antenna, and the folk that had been suffering from adjacent channel interference also noticed that their digital reception quality had improved again. |
| After just one week, in early June the panels started to reappear at the top of the antenna, working downwards (i.e. the reverse of the removal process). |
| By the end of the following week all of the panels had been reassembled. |
| Towards the end of June, the analogue signals were routed back up to the rebuilt top antenna, and similar issues with adjacent channel interference were restored. |
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