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Old 13th May 2014, 11:28 am   #121
Gulliver
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Default Re: 405-Line VHF Aerials in 2013

Here's the H aerial on my mum's house in Letchworth. I think it's attached to a socket in the living room. We tried said socket for UHF television when we moved to the house in 1979 and got poor reception, but not zero.
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Old 13th May 2014, 1:24 pm   #122
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Default Re: 405-Line VHF Aerials in 2013

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Originally Posted by colly0410 View Post
I suppose until recently the UK was the the only country in the world with no VHF TV, unless someone knows different..
Also Hong Kong.
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Old 13th May 2014, 5:04 pm   #123
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Default Re: 405-Line VHF Aerials in 2013

Please stay on topic, this is a thread for displaying surviving examples of VHF aerials.
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Old 13th May 2014, 7:23 pm   #124
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Default Re: 405-Line VHF Aerials in 2013

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Originally Posted by Gulliver View Post
Here's the H aerial on my mum's house in Letchworth. I think it's attached to a socket in the living room. We tried said socket for UHF television when we moved to the house in 1979 and got poor reception, but not zero.
I wonder which transmitter it was aimed at? The vast majority of 'main' BI/III transmitters were vertically polarised, and the local/infill repeaters were generally horizontal-polarisation to get a bit of extra discrimination against the distant 'main' transmitters on the same channel.
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Old 13th May 2014, 8:48 pm   #125
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Default Re: 405-Line VHF Aerials in 2013

Re post 121, is that not a band 2 vhf FM aerial?
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Old 13th May 2014, 8:49 pm   #126
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Default Re: 405-Line VHF Aerials in 2013

Could this have been an FM aerial? Letchworth in Hertfordshire would have been AP/CP for television and vertical. I can't think of a horizontaly polarized transmitter in your area.
Just a thought. John.

Last edited by Heatercathodeshort; 13th May 2014 at 8:50 pm. Reason: Sorry Nuvistor! Snap!
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Old 13th May 2014, 10:27 pm   #127
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Default Re: 405-Line VHF Aerials in 2013

Hi,

Thanks to AC/HL for sorting out the pictures and to Graham for pointing out how to get the file names!

Yes SteveCG you're right, the first picture is just a few metres south of the Abbey Hotel. I fact I took the picture from the hotel steps. I guess you know Malvern quite well!

Thanks for the suggested transmitters Brian. Sutton etc. is a bit East of North from the Malverns and is the obvious transmitter to use from the Eastern side of the hills. The array in photo 1 is pointing roughly due East, so I'm guessing that transmitters in the Oxford direction would be more likely. I think Ridge Hill and Wenvoe would both be behind the Malvern Hills in the opposite direction. I don't know why they didn't use Sutton. Maybe they wanted London regional programs rather than Midlands?

Steve.
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Old 14th May 2014, 5:31 am   #128
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Default Re: 405-Line VHF Aerials in 2013

Quote:
Originally Posted by Heatercathodeshort View Post
Could this have been an FM aerial
To be honest I don't know for sure. I've always been under the assumption it was for VHF TV. The previous house owners who lived there from the late 60s to 1979 both died and I don't think anyone else on the road has been there significantly longer...not long enough to remember VHF TV.

I believe that H is still connected to a socket in the living room, which gives a poor signal for UHF TV but also a poor signal for FM radio as we tried it for both...figuring such an aerial might be good for FM in the 80s.
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Old 14th May 2014, 10:28 am   #129
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Default Re: 405-Line VHF Aerials in 2013

Steve_FPV,

I think those aerials near the Abbey hotel are both J-Beam designs by the type of junction boxes they have. In which case the Band III is a channelised design - compared to J-Beam's later broad-band offerings. Perhaps you might be interested to try looking on St Andrews road in Malvern for some more J-Beam designs on a little bungalow estate just set back from the road. They were there a few years ago: one was a combined BI & BIII, the other an 8 el Broadband Band III with a separate 'H' design whose dimensions look suspiciously like those of a Channel B3 and not the Channel B4 it should be !

BTW Oxford used horizontal polarizations on B2 and B12, but they would be weak in Malvern. I can only assume that ghosting off the Malvern Hills and obstructions like the Malvern Priory as well as the Abbey Hotel made for the compromise pointing direction.

There is an Antiference Combined X and 8 el on the roof of a Chemist's shop just beside the traffic lights in Malvern town centre that points to the Hills and not directly towards Sutton C. & Litchfield.
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Old 14th May 2014, 1:09 pm   #130
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Default Re: 405-Line VHF Aerials in 2013

Quote:
Originally Posted by Heatercathodeshort View Post
I can't think of a horizontally polarized transmitter in your area
looking at lists of transmitters I would hazard a guess at Peterborough for BBC and Sandy Heath for Independent. Certainly we still get radio and digital TV from Sandy Heath.

Details given as:

Peterborough 5H 1 5.10.59
Sandy Heath 6H 30 13.7.65
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Old 14th May 2014, 1:47 pm   #131
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Re: Gulliver & Letchworth H aerial

Does the aerial point north ? If so,then it could indeed be Peterborough 405 line TV, channel B5. I've seen B5 TV aerials in Cambridge pointing to Peterborough - and that is at a comparable (but slightly less) line-of-sight distance to the Peterborough TX. I suspect it would have been "fringe" grade reception - but perhaps with less SpE interference than B1 from Crystal Palace.

Peterborough's service area map for B5 has field strength contours that are almost perfectly circular!
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Old 14th May 2014, 2:33 pm   #132
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Default Re: 405-Line VHF Aerials in 2013

If Google Maps is to believed, it's pointing more or less East/West.
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Old 15th May 2014, 9:28 am   #133
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Default Re: 405-Line VHF Aerials in 2013

Gulliver,

If the boom is indeed pointing E-W then I'm puzzled !

BTW: I reckon the aerial is a dipole-reflector H design, so the direction the aerial is pointing to will be along the boom, with the dipole downlead junction box nearest to the transmitter. Hence you can work out whether the aerial is pointing East or West. Should it be East then Manningtree on channel B4 would be the only possibility; but I would have thought co-channel interference with Sutton Coldfield would have been a serious problem.
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Old 15th May 2014, 9:38 am   #134
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Default Re: 405-Line VHF Aerials in 2013

I'm not at all familiar with VHF television apparatus but I've attached a doctored photo showing the property from above (Google Maps). The other photo which I took on Saturday was taken from the front driveway. The Google Maps is standard North facing up, East to the right etc.
I hope that helps you figure out the orientation of the aerial.
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Old 15th May 2014, 9:52 am   #135
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Default Re: 405-Line VHF Aerials in 2013

Sorry Gulliver I can't !

However, on your photo the dipole junction box is the furthest away from you, ie it is over the chimney pots. Does that help?

BTW a dipole junction box is where the two thinner diameter rods that, in aerial terminology, make up the dipole are physically mounted on the larger diameter boom and the downlead connected to them.
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Old 15th May 2014, 10:18 am   #136
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Default Re: 405-Line VHF Aerials in 2013

In that case the junction box is at the South end, with the central boom pointing more or less N-S.
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Old 16th May 2014, 10:06 am   #137
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Default Re: 405-Line VHF Aerials in 2013

Thanks for that Gulliver.

Well I double checked the lengths of the elements on your photo. The non-dipole elements are slightly longer than the dipole. In aerial design that means that they act as a reflector, and as such will be positioned on the boom furthest from the transmitter. In other words the aerial is indeed pointing to a transmitter to the south. However I cannot think of any old 405 line era TV transmitter in that direction which fits the bill. The aerial could be a VHF/FM aerial - which due to the dipole junction box being over the chimney pots has corroded connections due to coal smoke, hence you finding that it did not work back in the 80s.

I noticed you also have two UHF aerials on the chimney stack. What local TV news and weather does your mum receive? Is it London and/or East Anglia? This info can give a clue to possible transmitter sites since transmitters are grouped into regions and Local TV news and weather are regional programmes.
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Old 16th May 2014, 12:27 pm   #138
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Default Re: 405-Line VHF Aerials in 2013

Quote:
Originally Posted by SteveCG View Post
I noticed you also have two UHF aerials on the chimney stack. What local TV news and weather does your mum receive? Is it London and/or East Anglia? This info can give a clue to possible transmitter sites since transmitters are grouped into regions and Local TV news and weather are regional programmes.
Its possible the dipole isn't connected to anything...could be that the poor but extant reception is simply a cable in the wall going up to the roof.

When we moved there in 1979 there was also a wire wound multiple times round the inside of the loft, would round the wooden beams at the edges. We figured this was some sort of radio reception/transmission apparatus but had no further knowledge.

She gets Anglia. In the days of analogue TV we used to get a really good Anglia signal, I always thought from Sandy Heath? We could get Central but with a lot of snow, depending on the weather conditions.

At least one of those UHF aerials on the roof still works, though she's currently using a huge one inside the loft that I had fitted in the 80s.
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Old 16th May 2014, 1:27 pm   #139
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Default Re: 405-Line VHF Aerials in 2013

Because Band 1's range was 47-68Mhz for most of Europe ch B1 was not effected by co channel interference. In West Cornwall the main Redruth transmitter used B1 but re broadcast B2 from North Hessary Tor and so would re broadcast the B2 co channel interference. From 1970 they fitted a 625-405 line convertor and BBC 1 405 reception from Redruth was greatly improved during the summer months with its programme feed coming from the new Caradon Hill BBC1 625 outlet via the line convertor. The only co channel interference was some very slight patterning on the picture and slight interference to B1 audio from the lowest Band 1 French 819 line TV channel. I remember a few people in parts of west Cornwall who were out of range of the new 625 line service turning their BBC1 405 aerials to Redruth instead of North Hessary Tor to take advantage of the improved interference free reception now available from Redruth.
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Old 16th May 2014, 1:35 pm   #140
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Default Re: 405-Line VHF Aerials in 2013

Gulliver,

Indeed the dipole may now be connected to nothing. I have a neighbour whose external TV aerial's downlead is just gently flapping in the breeze connected to nothing.

Sandy Heath would be your local Anglia TV transmitter (in an approx Northerly direction). The main London transmitter, Crystal Palace, would be due south. Does your 'huge' aerial have a red dot on it or something which says Group (Gp) A ?
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