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THE TRANSMISSION GALLERY

Photos by Ray Cooper Page last updated: 2017-03-24
Cefn-Mawr Wrexham
NGR: SJ267409 Maps: Google  Bing (Ord Surv) Site Height:       Structure Height: 20m
Digital TV: BBC A: 57 D3&4: 53 BBC B: 60
BBC Radio:
 
Ind. National Radio:
Ind. Local Radio:
Digital Radio:
Comments: Cefn-Mawr is a relay of Moel-y-Parc (via Wrexham-Rhos). Cefn-Mawr B decommissioned at DSO

This site is odd. It is situated on a steeply sloping, partly wooded hillside, and is very difficult to see from the valley floor. When you've found it, however, you can drive to within 50 yards of the site on a public (?) road.

In analogue days it contained two sites: 'Cefn Mawr' (channels 51/44/41/47, 34W - some say 10W - vertical) and 'Cefn Mawr B' (58/64/61/54, 160W horizontal). A listing from 1995 fails to mention Cefn Mawr B, so this was evidently opened after this date - perhaps 1999-ish, to cope with some digital interference anomaly? This area was notorious for such problems. Cefn Mawr B was decommissioned at digital switchover.


View of site compound from adjacent footpath, looking roughly west. The furthest, largest cubicle looks to be the oldest (lichen-covered in places) but has air-conditioning units on exterior - not a feature of broadcast huts, so probably in use by mobile operators. This cubicle mounted on steeply-sloping ground, supported by steel pillars surrounded by mesh screen (to stop any aggrieved neighbours setting a bonfire under it???)


The site from higher up the footpath. Stone retaining wall holds back the hillside. Cubicles have been wangled in wherever possible.




Two different sets of transmit aerials are clearly visible, but the receive aerial is a bit of a mystery - there's no conventional log-periodic or trough visible on the mast.

The parentage of this station has also a little obscure. Although listed as a Moel-y-Parc dependant it never got its signals direct from MYP but from Llangollen. This arrangement was put in jeopady by the introduction of DTT services from Winter Hill and further complicated by the need for Cefn Mawr B which became necessary due to some interference from the Sutton Coldfield DTT services.

There is evidence that an SHF link was proposed to replace the RBL from Llangollen but we are unclear about whether or not this actually happened, SHF links being an expensive proposition for such a small relay.

It is possible that Wrexham-Rhos is now being used as the source for this relay but three of the Wrexham-Rhos channels are co-channel with Storeton, which is very much in the same general direction. Although Storeton radiates most of its power away from this direction, there might well be enough to cause co-channel interference. So you'd need a rather special receiving aerial.


Is that the explanation for that curious-looking 'panel' aerial mounted towards the bottom of the mast? There could be almost anything inside there: but it looks very much like a standard (horizontally-polarised) transmitting-aerial panel. If so, mounted on its side, you would have a broadside array of vertically-polarised dipoles in there, which wold give a narrow acceptance beam surrounded by deep nulls: wangle a null onto Storeton, problem solved. That's my guess - any amendments gratefully accepted.

[Ed.] The panel aerial is indeed a vertically polarised receive aerial for Wrexham-Rhos.




A curiosity. This silly little 2-element plus reflector yagi is pointing roughly north, but I don't think its anything to do with TV, and if it is then it's most unlikely to be the main RBL aerial!


The view northwards from the site. The white diagonal line across the middle of the picture is the water in the Pontcysyllte Aqueduct on the Llangollen Canal. At the far end of the aqueduct is a boat pondering whether to come across or stop for a cup of tea. The village above and to the left of the boat is Trevor: the remaining houses and industrial buildings to the right of Trefor are the western half of Cefn Mawr village.

I managed to grab this site opportunistically, but it was getting late in the day and the light was failing - some of the photos have been enhanced slightly but the 'landscape' one looks a bit like it's been done by a 'pointilliste' artist. (Maybe I should try selling it as such...) This site is of more than average interest, and I may well go back at a later date to get some better pictures.

Llangollen UHF | Storeton | Wrexham-Rhos

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