Impressive domestic TV aerial installation picture from the past

Antenna

The attached picture is of a DX TV aerial installation on a house in the coastal town of Tramore Co. Waterford which appeared in Television magazine in January 1984. It was equipped with two separate high gain quad stacks for reception of TV signals from both S.W. Wales and Cornwall. - Came across it while looking through a pile of old Television magazines someone gave me! Take a look, interesting.

Mossy Monk

wow
that man sure does love his uk terrestrial tv
Caradon Hill not enough for him so he goes for Presley aswell

fair play

Ulsterman 1690

Ive seen more elaborate than that take a drive through rural Kildare and look at the massive towers on some peoples houses. Do they ever get hasstle from the planning nazi's ? I certainely wouldnt fancy having one of those things on my roof during a thunderstorm :eek:

One reason people in SE Ireland might want to use Cornwall rather than Wales is to get proper Channel 4

legend99

Pardon my ignorance...but why does he need more than one aerial pooiting at the same trxs? Ok, i know it would need 2 to point at the 2 trxs. but why more than that???

Mossy Monk

better signal gain if i'm correct

lawhec

legend99 wrote:

Pardon my ignorance...but why does he need more than one aerial pooiting at the same trxs? Ok, i know it would need 2 to point at the 2 trxs. but why more than that???

If you set up several receiving aerials in a certain way and then combine their signals you can both improve your wanted signal and reject interference. In it's simplest form you have two aerials side by side with the feeds from both aerials sent to a combiner - it is vital that the lengths used are exactly the same or phase cancelling can occour, however phase cancelling can also be useful, if you set the two adjacent aerials to be say x.5 wavelengths apart of the wanted signal, then any unwanted signal that comes from the side of the first aerial will reach the other aerial at a completely (180 degrees) different phase. When the signals from the two aerials combine, the unwanted signals will be out of phase with each other and will then cancel. A similar technique can be used when dealing with unwanted signals from the rear. There is an good article on this in this month's "Television" magazine.

In the case of this guy's setup, combining four aerials can give a 6db increase in the wanted signal after the combiner (four times more signal) before presumably being amplified. It also has a narrower forward acceptance angle which helps reduce interference from unwanted signals.

Such 4-aerial setups aren't seen very much as they'd be regarded as overkill. There is one at the Citywest Hotel directed at Divis, but they've replaced thier feeds for BBC1, 2, UTV and Channel 4 with FTA/V Satellite setups. Two aerial setups however are fairly common in fringe areas like rural Kildare. I believe a 16 aerial system was once used to operate a "deflector" in Limerick city, taking it's signals from Brougher Mountain. I also believe that a 24 aerial system also existed in Alderny in the Channel Islands as a backup to the SABRE system when it was used there.

My uncle in Hazelhatch has a 110ft mast with four vertically polarised group A aerials for Divis. The mast also has a horizontally polarised grid, probably for RTE/TV3 from Three Rock. Reception is pretty good, not bad for free.

Ulsterman 1690

four vertically polarised group A aerials for Divis

But Divis is horizontal

And the only relays of Divis on Group A Vertical are Benagh, Cushendun and Killowen Mountain which are hardly recievable at the location in question

Yeah sorry, haven't been there since 1998 so the memory isn't serving me too well

Ulsterman 1690

In it's simplest form you have two aerials side by side with the feeds from both aerials sent to a combiner

NC what kind of combiner do you use for this ? Id imagine most combiners/splitters (especially those crappy "white y splitters") are so lossy as to defeat the purpose

lawhec

Ulsterman 1690 wrote:

NC what kind of combiner do you use for this ? Id imagine most combiners/splitters (especially those crappy "white y splitters") are so lossy as to defeat the purpose

I only know the theroy behind it as I've not had the chance to try it myself. The combiners required would be high quality, low instertion loss.

legend99

Thanks for the info guys.

Marcopolo85

Northern Correspondent wrote:

I only know the theroy behind it as I've not had the chance to try it myself. The combiners required would be high quality, low instertion loss.

The combiners for these are usually purpose-built and supplied by the aerial manufacturer.