405-Line VHF Aerials 2013 to the present day.

[colly0410]

Originally Posted by ntscuser

Has anybody spotted one of these yet? It's a combined Band III vertical/Band V horizontal aerial for Winter Hill. Have to admit I visited Bolton often in the 1960s and never once noticed that BBC and ITV were both on Band III.

Remember seeing some of these type in Lincolnshire pointed at Belmont for channels 7 & 13. Belmont was a bit of a latecomer with UHF for BBC1 & ITV as they didn't fire up till 1971..

[Hybrid tellies]

I saw several of these combined band 3 VP and band 5 HP aerials on the Wirral Merseyside for BBC1 ch12, Granada ch9 and BBC2 ch62 from Winter Hill.I think they date back to the mid-late 1960's just before BBC1 and Granada joined BBC2 on UHF 625 in late 1969.

[ntscuser]

The picture is from the trade news section of the August 1965 edition of PTV.

I would have thought the VHF elements were superfluous after 1969 since even if people still had a 405-line receiver they could probably feed it from an existing Band III aerial.

[Nuvistor]

BBC1 Channel 12 from Winter Hill started transmission in I think 1966, 3 years before BBC1 and ITV began on Band 5.
We had very good coverage for UHF so we fitted only UHF aerials after the three channels went onto UHF. However it is likely that even after 3 channel uhf went live from Winter Hill there would be pockets of poor UHF reception and Band 3 would remain in use.

[Hybrid tellies]

The same situation existed around Bath. Even in the late 1970's there were quite a few pockets that were out of reach of either the Mendip or the local Bathampton UHF transmissions where our customers had to stick with the VHF 405 service either from the local Bathampton relay with BBC1 on ch6 and ITV on ch8 or from Wenvoe/St Hilary with BBC1 on ch5 and ITV on ch10. It was fun keeping the last generation dual standard tv's such as the BRC 1400'S and RBM A640'S going for so long.
Despite these areas having quite a weak 405 signal they could use quite modest VHF TV aerials to get acceptable reception

[G6Tanuki]

Same was true around here in Marlborough: it was in a kind-of UHF black hole between Hannington Mendip and Rowridge.

So there are still quite a few extant small 3- or 5-ele Band-I/III horizontally polarised arrays pointed in the general directon of Membury and Hungerford.

I know of one horizontally-polarised antenna in Hungerford that is a top-end B1 array with a couple of 'prongs' fitted to the dipole to give BIII reception: almost opposite the "Dick Lovett" BMW dealership.

http://www.wrightsaerials.tv/aerialp...ient/075.shtml

[Picture I supplied to Bill Wright's excellent site a few years back].

[ORTF_&_Co]

Originally Posted by Synchrodyne

That I don’t know. It certainly seems to be an odd allocation, though. Perhaps ORTF & Co can help here. (...)

Hello, sorry I could not reply sooner.

In fact, 819 lines ch F3 was never used in France. Only one transmitter was initially planned in Tours with this channel, but it was never built and this channel was not even incorporated in the receivers' channels selectors.

I presume that the previous experience of regular long distance reception of 441lines band I transmissions, incited the RTF tp avoid the risks of severe interferences in using a channel overlaping both channels F2 and F4.

With 625 lines system L' on VHF in the Eighties, the problem was slightly different because most of former 819 lines band I channels had been replaced by new band III channels (in Troyes, Caen, Nantes and Limoges), except for transmitters received in neighbouring countries : Bastia (Eastern Corsica) on ch L2 (49.25-55.75 MHz) and Ajaccio (Western Corsica) on ch L4 (57.25-63.75 MHz), both received in Italy.

Both other band I transmitters formerly on ch F4-V, Besançon and Carcassonne, were retuned to new ch L3-V (54.00-50.50 MHz) instead of ch L4-V (57.25-63.75 MHz). I presume this was intended to reduce possible interferences with neighbouring Swiss transmitter at La Dôle, and Spanish one in Barcelona, both using ch E4-H (62.25-67.75 MHz), furthermore French
transmissions were mostly encrypted.

Please note that for a better comprehension above, I mentioned French L' frequencies in the same way as for 'E' channels, that are infradyne (audio = video freq.+ 5.5 MHz) while French band I 'L' channels were supradyne (audio = video freq. - 6 MHz).

[Synchrodyne]

Thanks for that. I can now see where channel L3 fitted in; namely just below and clear of channel E4, and as it happened just above and only just clear of channel E2; also still within the range of channel F4 aerials.

By the way, I hadn't previously seen the terms "infradyne" and "supradyne", but they are nicely concise and descriptive.

Cheers,

[Rhgbristol]

The attached photo was taken today on a building in Westbury on Trym, Bristol not far from where I live.

It is the corner of Stoke Lane and Back Stoke Lane, and the building is now a restaurant.

In the 1960s I'm told it was a tv and radio shop, which would explain these aerials.

On the main mast, there is a band 1, band 3 and uhf aerial, all still correctly pointing to Cardiff. The band 1 and uhf aerial would have been aligned to wenvoe, whilst the band 3 aerial pointing in the same direction would have been aligned to st Hilary which was the IBA transmitter also in Cardiff.

At the time this is how Bristol was served as it was not until about 1970 when the Mendip transmitter started covering Bristol for uhf tv.

Even after that time, this part of Bristol was still shadowed by land from good Mendip reception and the Wenvoe mast often gave good reception. It was not until the mid 1970s when this part of Bristol received its own UHF relay masts - in this case the Kingsweston mast using vertical polarisation uhf.

Clearly the UHF aerial in this array was not realigned for the newer relay mast unlike many in Bristol.

The array and mast here probably dates from the period 1965 to 1972 I would guess.

From my knowledge, these three aerials were made be a local aerial manufacturer called Telefield who were based in Kingsland Road, Bristol.

I remember going to the Telefield factory several times in the 1980s as a teenager to buy components to make my own aerials, and the proprietor was always very helpful and gave me the dimensions for aerials to make my own with his components. I still have some of his hand drawn sketches from 1984 in my files.

The Telefield aerials in this picture were very well made - the fact they are still there 50 years later proves this.

The uhf aerial was made from round three quarter inch boom, with three eighths inch split tube round elements. Plastic blocks were used between the boom and elements with 4BA nuts and bolts to secure.

The band 1 aerial was 1 inch boom with half inch round elements.
The band 3 aerial was 1 inch boom with three eighth inch round elements.

The aerial on the other mast is clearly a band 2 FM radio aerial, again made by Telefield I believe.

Clearly this FM aerial and its mast have swung in the wind, as it too should have been directed at the Wenvoe mast for radio coverage in this part of Bristol.

There are many examples of Telefield aerials of this vintage in Bristol still up on roof tops to this day, and I will post more photos when I get can.

Telefield ceased trading some time in the late 1990s.

The last time I went in there to buy components must have been about 1996 or thereabouts - by which time, to make ends meet, the company was assembling also aluminium extrusions for camping equipment such as tents, etc.

Sadly the company was. a victim to cheaper products being imported from abroad I would guess or maybe retirement by the proprietor.

Does anyone here know anything else about Telefield I wonder ?

[SteveCG]

Re post no. 318:

There were two versions of Antiference's combined Band III/ UHF aerials. The picture shows the original (Mk 1 shall we say?). Note on it, the hanging balun junction box for the UHF and the near in-line junction box for the Band III. The Mk2 used the first version of Antiference UHF Trumatch dipole and the Band III junction box was the offset style virtually identical to the one used on later Band II aerials. Whilst the UHF trumatch dipole was an improvement, it was somewhat compromised by the Band III junction box being a serious fraction of the UHF wavelength for Group C so 'detuning' the UHF yagi design.

In my opinion Antiference would have been better to have kept the MK 1's Band III junction box. This UHF 'detuning' would have been less for the Belmont design with its Group A UHF yagi element lengths.

I can remember seeing quite a few of the Winter Hill designs in use around its service area.

[SteveCG]

Re post no. 319:

Just a thought: Winter Hill ITA channel B9 was virtually omnidirectional at 100 kW ERP, whereas Winter Hill BBC1 channel B12 was directional with a max ERP of 125 kW; so I wonder if the poorer BBC1 reception has anything to do with that as it would depend upon the receiver's location in the sevice area? It could also be due to relatively poorer tuner performance at the higher B12 frequencies.

[Nuvistor]

I believe the 125kW is a misprint but open to correction.

The transmission was indeed directional with the main lobes north of east and north west with smaller lobes to other compass points. the BBC engineering paper on this aerial states the maximum transmit power was 8.5kw with an mean aerial gain of 6.2 db and a mean ERP of 35kw. The main lobes correspond to around 35kw ERP (see polar diagram). I accept that various areas covered by the transmitter would have different signal strengths but I am not convinced about the 125kW ERP, more like 12.5kw on average.

see http://downloads.bbc.co.uk/rd/pubs/reports/1967-04.pdf

Frank

edit.When I say misprint, I know various information is available that quotes 125kw, I am not denigrating you post Steve

[SteveCG]

Re post no. 322

Thank you for that link Nuvisor. I was going on what the BBC said in its Tx handbooks - and a BBC service area map. I wonder if it started off at low-power and was boosted later on? I've got a dim recollection of that happening - but could be wrong; as SpE interference to the B2 signal from Holme Moss was quite an issue in the NW - so anything that was interference-free was taken up with alacrity, even if it was a bit weak.

Certainly to North of Winter Hill I saw quite a few 8 element Antiference semi-wideband (the CH B9-B12 version) aerials in action. Specifically around Lancaster City, but also further North and West of Lancaster. My own experience there was that B12 came through as well as B9. But I readily accept that a few dBs difference in signal strength when not 'beyond the fringe' is not as noticable as one may think.

[Nuvistor]

Hi Steve,
Yes they very possibly increased the power but the original installation was far a specific area that had bad reception of Holme Moss, hence the lower power.
We stopped using 405 when 625 became available in 1969 and many of our customers with dual standard sets changed to the 625 transmissions so I would not be aware of any increase in power after the early 70's.
I think it would have been a large undertaking to increase the power to 125kw ERP, the aerial and transmission lines would probably require replacing unless the original design had taken that into account, nothing is noted in the engineering documents in the link.

Have you a link to the BBC documents giving the increased power levels, it is all academic now but I find it interesting.

Frank

[ORTF_&_Co]

Originally Posted by colly0410

Remember seeing some of these type in Lincolnshire pointed at Belmont for channels 7 & 13. Belmont was a bit of a latecomer with UHF for BBC1 & ITV as they didn't fire up till 1971..

Here attached an Aerialite multi-band model ref. 345/5/11 shown in Wireless World's June 1966 issue, in an article about the London Radio & Television International Festival.

The caption says it is a bands I - III - IV and V aerial, but I think they sold customized aerials, depending on the transmitter involved. I can't imagine that band III folded dipole being able to correctly receive band I channels.

I imagine they replaced it by a band I dipole or maybe they added it to this array. You'll note that we can't see any connection box on that picture.

[Nuvistor]

I only saw these grouped to the area I worked, the transmitter was Winter Hill, BBC1 CH 12 ITV CH 9 and UHF Group C/D.
I think the Band 3 was broad enough for the CH 9-12, I cannot see how they woukd have tuned it to two seperate channels, group C/D was I think CH 48-68 could have been 49-68, but too long ago to be certain. The UHF Channels in use were 55,59,62 and then when it arrived 65 for CH 4.

[ORTF_&_Co]

Originally Posted by Nuvistor

(...) they very possibly increased the power but the original installation was far a specific area that had bad reception of Holme Moss, hence the lower power.
(...) I think it would have been a large undertaking to increase the power to 125kw ERP, the aerial and transmission lines would probably require replacing unless the original design had taken that into account, nothing is noted in the engineering documents in the link.

Have you a link to the BBC documents giving the increased power levels, it is all academic now but I find it interesting.

Frank

Here some copies of the World Radio TV Handbook from 1965 to 1970, and a BBC Engineering Information Sheet 1972 showing that, except at the very beginning, the BBC1 power at Winter Hill has always been 125 kW (ERP).
You'll however note that the WRTH specifies that it used a directional aerial.

The transmitter first used a 450 feet latice tower, that was later replaced by a 1015 feet twice higher tower. I presume that this is one of the factors that improved BBC1 reception on ch 12.

[ORTF_&_Co]

Last but not the least, some further material about Winter Hill.

About the Effective Radiated Power, I reckon the BBC technical report (PDF attachment) will be the most interesting to you. It gives lots of details and figures about the aerials, the pattern etc.

I just found it in my archive when closing this post. I can't remember where I found it.

I'm taking the opportunity of these first messages in 2016 to wish everyone here a Happy New Year.

Greetings from the Continent,

Louis-Marie

[Nuvistor]

The info about the ERP looks ambiguous, the 1967 BBC doc states a much lower ERP than the WRTH of the same year even allowing for the directional aerial.
The BBC 1972 quotes the higher ERP so I presume they increased the power at some time.

I could be wrong but I do not remember the ch 12 transmitter being on the 450ft mast only on the 1000ft one. the 1000ft mast came into service in 1965, ch 12 came into full service according to the BBC doc March 1966, so I presume it was with the specification in that document.

A couple of years ago I had a walk up to the mast at Winter Hill, very impressive standing near the base and looking up. A walk to be done in summer and with warm clothing, gets cold and windy on that moor. About a 5 mile return walk from Wallsuches Horwich, Tarmac road all the way but if you take a car you would need to leave it about a mile from the mast.
Warning signs in winter about falling ice from the mast and stays.

[Nuvistor]

Some photos of the Winter Hill mast and plaques on the wall of the transmitter hall. The rusty pole is directly across the tarmac from the transmitter hall and refers unfortunate soul murdered on the moor in 1838.