The first B/W UHF test transmissions in London were on Ch.30. When the channel allocations were eventually worked out we had 26, 26, 30 and 33 for ITV, BBC1, Ch.4 and BBC2 respectively, ie. a perfectly balanced arrangement, 2 channels funded by licence fee and 2 by adverts. Every region in the country had it’s channels chosen to reduce interference.
The gain of the original aerials for BBC1 rose gently from Ch.21 (the start of UHF band 4 up to Ch. 30ish and then fell sharply. By the time you got to Ch.33 it was well down so it was always more difficult to get a good signal for BBC2. Then our politicians decided to unbalance the whole system by inventing Ch.5 and which channel did they decide to put it on? Correct, on the gap between UHF 4 and UHF 5 at around Ch.35 to 37 which had been reserved for technical transmissions, so that’s where almost all manufacturers had put the output of their video recorders and so the whole country had to retune them!(if possible!). What a c**k up!
So you can see that the older UHF aerials were even worse for Ch.5 than BBC2! So, many people had to invest in newer aerials, indeed in some regions Ch.5 had ended up at the top end of UHF band 5 i.e CH. 60ish! So, wide band aerials became necessary. The best wide band aerial was the log-periodic developed by the BBC and made by J-Beam. The snag was that it had fairly low gain, c.8.5 db, whereas some narrow band aerials got up to 12+ db. I sold aerials for many years and the best were from a German company called Fuba, (because they used anodised aluminium, the UK used bare aluminium which corroded), but unfortunately they stopped making them to concentrate on satellite dishes. The European Group A aerial was ideal for London as it’s response went well up to Ch. 40ish, much higher than the UK Group A one. End of history lesson!
My neighbour had a new aerial recently and it is a log-periodic (heaven knows why!) so they must be being made by someone.
Mike Jordan
It doesn’t end here since in London, Comm7 and 8 are up at about channel 55/56 so really a wideband aerial is needed. However they are threatened with moving yet again at some time to allow more mobile phone channels.Comm 7 and 8 are also at a much lower power – about 40Kw as opposed to 200Kw for the main channels and there is a tiddly channel (29) for London Live – that truly local fascinating channel with about 10seconds of live news per day and loads of old movies and series.
HD channels are spread around everywhere although most BBC ones and the main ITV channels are in channel 30.
There are also problems with many sets since the coding varies with rate and bandwidth and datastream of the video at different rates (MPEG 3 or 4)
Also – mainly outside London – the channels are coded completely differently with shared allocations.
Lots at Crystal Palace although that is somewhat out of date.
Freeview SAY they will replace inadequate aerials but it is rather up to them what that means.
And so it goes on – back from Band I and Band III 405 eh?
Bernie Newnham
Can anyone be specific? e.g. – is this any good –TV Aerial 4G Filter Triple Boom 64 Element Freeview Digital HD?
Martin Eccles
Here is the ATV article about Crystal Palace and it’s new muxes 7 and 8.For Crystal Palace we recommend:
The DM log for strong signal areas,
the Log36 or Yagi 18K for medium signal areas,
the Yagi18A for outside installs in poor signal areas,
the XB10A for loft installations in poor signal areas,
and the XB16A for those with the most marginal signals.
Unless you have a massive loft we`d normally recommend the XB10A over the XB16A for a loft install due the smaller size of the former aerial.
* The A group aerials will not pick up MUXES 7 & 8: if you particularly want to receive those MUXES we still recommend:
the DM log for strong signal areas
and the Log36 or Yagi18K for medium signal areas,
but for weak areas we`d recommend the DY14WB, though you will lose gain on the 6 main MUXES compared to an A group aerial. Alternatively, diplex a Yagi 18E with your existing A group aerial (using a CH38 diplexer to get high gain across the whole band.
Muxes 7 and 8 are due to be turned off sometime between 2020 and 2022 so just hang on for 4 years and things may get back to normal.
