All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Nigel Vickers: At 9 miles, it "could" be too much signal, depending on your aerial system:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
If you have a booster, trying removing it or turning it down if it allows.
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Vince: See Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
BBC Two analogue has been turned off to allow the new full BBC digital service to use the same frequency.
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Deb: At the first stage of switchover, BBC channels go up to full final power; the rest remain as they were. Two weeks later, the rest follow and the rest of the analogue is switched off.
You haven't said which transmitter your aerial is directed to, so I will guess at the most likely ones which are probably Hastings and Heathfield. These are inbetween first and final phases of switchover, and thus ITV1, C4 etc may still be unavailable or intermittent.
The two regional options you are given are in fact a selection of transmitter. The transmitters carry the name of their main service area.
I guess that you need to select "East Sussex" for Hastings or Heathfield transmitters.
If having done this, you still have no ITV1, C4, then you may be able to try manually tuning it, if the receiver has a manual tune facility and if you can identify which transmitter you are using.
Are you referring to digital (Freeview) or analogue reception of ITV1 and C4? Do these sets use the same aerial?
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Terry, Mark Fletcher: I think even if Terry's aerial is a wideband, that it will work if it has worked before, which it clearly has.
Whilst it is true that the gain of wideband yagi aerials is lower on Group A channels, if it has been proven to work, then I see no reason to replace it.
I think that one of the main issues that Terry and other users of Rowridge have to contend with is the fact that the Commercial multiplexes are only 50kW horizontally whereas they are 200kW vertically (and the Public Service channels are 200kW vertically and horizontally).
So there is a marked difference in strength horizontally and this is probably the biggest issue.
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H. Gravett: Whilst Newhaven will probably be your best transmitter from a signal strength point of view, it will not provide the full range of Freeview channels as it will only carry Public Service Broadcaster (PSB) multiplexes.
Refer to DMOL Post-DSO Multiplex Channel Allocations for the three PSB multiplexes ("muxes"). The Commercial muxes, known as the COMs, are only broadcast from the bigger transmitters. The COMs are shown below the PSBs on that page.
For this reason, you will probably wish to attempt reception from a transmitter that carries the COMs. You "may" find that the aerial needs to be outside above roof level in order get enough signal from one of these other transmitters. There is probably little to be lost by experimenting in the loft.
I think that Heathfield will probably be the first one to try. As Newhaven is a relay of Heathfield, you will get the same regional programming.
If your neighbour's property adjoins yours in the direction of Heathfield, then this will probably rule out reception in the loft. That is, if the aerial is to be pointed through your neighbour's loft space, then I think that there is little hope of success.
If your Newhaven aerial is a Group B one, Heathfield is Group B as well (or it will be once switchover has completed). For Heathfield you will need to switch the aerial from vertical to horizontal. Heathfield's full-power post-DSO BBC mux is on C52 (this is what Newhaven is rebroadcasting on C50). All other digital channels from Heathfield are still on their pre-DSO low power and so may be unavailable.
There isn't forced to be a need to replace the lower grade cable. With digital, there is signal strength and signal quality. The strength needs to be above the threshold at which the receiver will resolve a picture. Signal strength can vary a little, e.g. with the weather. With analogue, a slight variation would have some direct impact on the picture, maybe slightly more grain. With digital, there will be no impact unless it puts the level below the threshold, at which point the picture will be lost or perhaps intermittent break-up will occur.
From what you've said, the channels for which some receivers pick up and some don't are those from another transmitter (for which the aerial wasn't installed for and for which you aren't likely to watch). So they may be marginal strength anyway plus the fact that different receivers have differing sensitivity to (presumably) such small signals.
As you're using one aerial for more than one set, then there should be a proper method of splitting the signal. A distribution amplifier will ensure that equal levels of signal are given to each feed. An unpowered splitter may be sufficient where there is sufficient signal going in.
The downleads should not be connected under the aerial terminals or connected using a terminal block or twisted and taped together; a proper splitter should be used.
If you are looking at DIYing, or just wish to be briefed before getting in a professional, then have a look at www.aerialsandtv.com which has a page with guidance on selection of aerial for the transmitter: Heathfield Transmitter
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Maurice: It's good to hear that your son now has his channels back.
Let us know if you have any issues next week.
You will have to retune again on 27th because SDN (ITV3 etc) from Tunbridge Wells will be changing channel. It will also remain at a power of 100W until 27th, so you may have difficulty picking it up until then.
I presume that this delay is due to Blue Bell Hill and Dover transmitters using C42 until they complete switchover on 27th. C42 is the channel used by TW for SDN after switchover.
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Terry: If you have a booster, then try removing it. Keep the aerial vertical as that is definately the best for Rowridge.
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Terry: If you do decide to get another aerial, you might like to take a look at Rowridge Transmitter
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Gerald Maguire: You should have BBC channels as they have switched over.
The rest will follow next week; they remain on their pre-switchover low (restricted) power until then.
If you have difficulties then, let us know on here and we may be able to suggest how to proceed.
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Sunday 3 June 2012 8:20PM
Terry: Yes, vertical will be better as all signals are the same power vertically.
Horizontally the Commercial multiplexes (which include Film 4) are weaker than the Public Services ones (BBC, ITV1, C4, C5 etc).