405-Line VHF Aerials 2013 to the present day.

[HamishBoxer]

Despite the hard climate, many large Band 1 arrays are still surviving up here in the frozen North. Must post my pictures from Grantown-On Spey.

[crusher19860138]

Originally Posted by Nicklyons2

And here's another great survival - even the UHF on this installation is pretty ancient.

I bet the UHF is still giving good service as well!

[crusher19860138]

Saw a double six Band 3 aerial on a high south facing wall ,atop a 20 ft pole in Ludlow recently, I guess it must be pointing towards Wenvoe?

[Tazman1966]

More than likely St Hilary on channel 10.

[SwanseaSteve]

Could have been either St. Hilary or Wenvoe. From 1963 Wenvoe radiated 200kW EIRP on Ch13, and from 1965 St. Hilary was radiating Ch10 towards the South West of England and Ch7 northwards towards Wales (and the Ludlow site mentioned here).

But from Ludlow, surely Ridge Hill on Ch6 was a better bet?

[Focus Diode]

Originally Posted by SwanseaSteve

But from Ludlow, surely Ridge Hill on Ch6 was a better bet?

I thought that too, but Ridge Hill ch6V didn't open until 30/07/68!

Brian

[SteveCG]

A couple of thoughts on the Ludlow aerial:

1) Ghosting may have been a problem from Ridge Hill (RH) - hence a double;

2) The aerial could have been orginally pointed to Litchfield, and just turned when
RH opened. Many aerials in Hereford city, originally for Litchfield, were just turned when RH started; and a CH 8 aerial will work acceptably on CH 6.

[SwanseaSteve]

Even here in Swansea, a South Wales coastal town famous for its wild weather off the sea, I do know of a couple of Band I aerial installations still standing. No sign of any coax leading to them though - I imagine that the constant flapping in the breeze has done for the cables by way of metal fatigue long ago.

Worth keeping in mind that there might be a number of Band III aerials on roofs there days for the purpose of receiving DAB radio. In many cases, these might even be pointing at the same masts as Band III television aerials once did! I suppose the differences that give the game away would be that the DAB aerials are shinier, and do have coax cables attached.

Apart from that, they're going to look identical (though they're actually very slightly smaller that an old 405-line channel B13 aerial). DAB is transmitted on channels whose numbers are based on the European 7-MHz system B channel numbering, and here in the UK we seem to be mostly using channels E11 and E12 (216 - 230MHz) for the job.

[Nicklyons2]

It's not only the shining metal which gives away the new Band III aerials it is also the gauge of the metal, the often strange folded dipoles with huge connecting boxes and the eccentric spacing of the elements, (I would suspect), to get a measure of broadbandiness whilst staying compact.

[ntscuser]

The multi-element DAB aerial for a nearby flats complex is pointed towards the old Lichfield ITV transmitter and is definitely powerful enough to pick up a TV signal from there if there was still one. The elements are much closer spaced than usual and raked forwards but as far as I can tell (from ground level) it is not a log-periodic design. I've so far been unable to determine its make or find a picture of one.

[crusher19860138]

I remember walking past a cottage at Rodley,Gloucestershire around 1981,and seeing a double six in the front garden on a 15ft pole,pointing roughly NW,as all other aerials were by this time UHF and pointed the opposite way towards Mendip,i stopped outside this cottage for a break as it was a hot summers day,the cottage window was open and i remember hearing the ATV ident tune,happy days!

[Focus Diode]

A couple of great examples spotted in the Kings Cross area of London over the past couple of days.

Note the folded CH1 X-dipole in the first photo. The second was spotted this very morning on having breakfast inside a hotel in the area. The CH9 array looks to be an Antiference "Trumatch" design. There was another ch1 & 9 set up which had collapsed a house or two away. Nearby UHF aerials have been painted out for clarity.

Cheers,
Brian

[malvision]

The easiest way to Aerial spot, is using google maps street view. Quite interesting how many 405 aerials you see, if you pick the right areas.

[colly0410]

Would a folded X work any better than a normal X or was it a gimmick?

[SteveCG]

Re post no. 24

An interesting question! There was a maker/brand? 'Dublex' in the late 40s - 50s who made such an aerial. A moderate pig to take apart - unlike the Antiference Antex X. If I remember correctly the elements were internally connected in a different way to the Antex. With twice the amount of metal they must have been more expensive than the Antex, but I bet the performance was similar - possibly a difference in the impedance??

Perhaps somebody with a good back collection of Wireless World adverts of that era could establish who came first in the X design league?

[G6Tanuki]

Originally Posted by colly0410

Would a folded X work any better than a normal X or was it a gimmick?

I guess it depends on how they were connected up: if the ends of each 'leg' were simply paralleled at the feedpoint it would work as a fat element and this generally gives increased bandwidth compared with a single thin element.

This would only really be relevant though if you were trying to cover several Band-I channels where the frequency range is large compared with the resonant bandwidth of a half-wave element.

Some of the currently available DAB and Band-II dipole antennas _appear_ to be a folded dipole but the ends of each leg are paralleled at the feedpoint to give a 'fat' element.

[colly0410]

When I lived in Bestwood Village near Nottingham we had a strange looking aerial, it was like a bent H with the dipole & reflector at about 45 degrees, sort of like two V's sideways on, we didn't have a seperate band 3 aerial. How did it work? My theory, (probably wrong) on band 1 a slightly degraded bent dipole + reflector. On band 3 as it's about 1.5 wave-lengths long it acts as the front (or is it the back) of a rhombic aerial.... BTW it was a good FM aerial till the wind blew it down in the late 70's. (I was in the Army in Germany so couldn't salvage it.)

[G6Tanuki]

There was at least one design of combined B1/B3 antenna like you describe, though not all of them had the "delta-wing" swept-back style (this was probably more based on marketing than RF theory!)

The usual approach was that the boom part was actually a transmission-line and both the elements of the "H" were connected to the antenna feedpoint, one set directly the other via the transmission-line, in the style of the "ZL Special" or "HB9CV" 2-element beams used by us amateur-radio types.

On B3 it would work like the HB9CV/ZL and provide a bit of gain/directivity; on B1 one pair of elements would have been largely irrelevant, the other pair would be a 'short' dipole brought up to resonance by the transmission-line boom, and probably be a few dB down on an undistorted dipole.

Alternatively could it have been something like this:

http://www.wrightsaerials.co.uk/aeri...ient/019.shtml

--G6Tanuki

[ntscuser]

Originally Posted by G6Tanuki

Alternatively could it have been something like this:

http://www.wrightsaerials.co.uk/aeri...ient/019.shtml

That looks very much like the modern-day DAB aerial mounted on a nearby flats complex!

[colly0410]

Re post # 38... I never thought about both elements being driven, I just assumed it was some kind of bent H. It seemed to work OK, my mate a few doors away had an X for BBC + a 5 element yagi for ITV & our reception was just as good as his. I never saw it close up as when it blew down it must have been binned, when I came back from Germany it was gone..