All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Ron Scholes: The other three multiplexes that you do not receive are operated by the Commercial companies and they can choose where to install their transmitters.
The Lulworth transmitter is like 1000 or so other small relays; Public Service only.
The Commercial broadcasters achieve around 90% coverage of the population by transmitting from about 80 of the largest (by viewer population) sites. To transmit from the rest would roughly double their cost of transmission.
They are profit driven organisations that sell advertising to advertisers and show their output to as many viewers as possible at the lowest cost.
For a fuller explanation, see here:
Will there ever be more services on the Freeview Light transmitters? | ukfree.tv - independent free digital TV advice
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Jean: Can you give the model number of the DVD recorder that is causing the problem?
Perhaps the issue is caused by it finding too many channels than it can hold in the memory, which causes it to "forget" some and therefore regard them as "new" when it is turned on. It is quite possible that some of these channels that are clogging up the memory are ones from another transmitter (Hannington, Mendip) and not Oxford. Are there channels stored in the 800s and if so, how high do they go (what is the highest)?
There may be an option in the menu to turn of notifications of new services if you cannot cure the problem another way.
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John Beeston: Which services are you having issues with?
Digital UK Tradeview predictor suggests that Dover will be best for you both now and after switchover, it giving "good" across the board and after DSO. Is there a reason that you can't receive from Dover?
If you are using Blue Bell Hill, a wideband aerial will be needed (or combined Group aerials).
Blue Bell Hill uses C24 for Mux 2 (ITV1 etc) and C27 for Mux A (ITV3 etc). The predictor suggests you will have "poor" reception on these, whereas the others are better, them being "variable".
On 7th March, the power of C24 and C27 from Reigate went up to 2kW and 1kW respectively. This was done because Rowridge which serves a big chunk of the south coast and uses these channels switched over on that date.
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John: Different receivers work differently and some may be more sensitive to others. That is both sensitivity of signals and immunity to interference.
I would not read anything into "Freeview" and "Freeview+" as these are simply brand names associated with non-recording and recording devices.
Have you had your Group A aerial replaced with a wideband one (or a second Group C/D aerial fitted)? If you haven't had this done, then that will explain poor reception of the COMs. If you would like me to explain what this means, then let me know.
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mr p lees: If there are, then they are operating illegally as the licences haven't been auctioned yet.
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jonny: That is correct. Those whose reception of SDN, ArqA and ArqB *horizontally* is not good enough can switch to vertical polarisation.
The power before switchover was 20kW at 260m above datum. So now the radiating antenna array is higher as well.
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Frazer Palmer: Oh no it's not!
Switchover "completes" for Southampton, Portsmouth and Brighton | ukfree.tv - independent free digital TV advice
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Bob Hobbs: Whitehawk Hill is not transmitting BBC South. Any BBC South you are picking up is coming from another transmitter and it is this issue which you need to address.
Based on the Digital UK Predictor, the signal from the Findon transmitter (which is on the hill to the north of High Salvington), which carries BBC South, is good where you are, so I think that this is the most likely candidate, with Rowridge being less likely.
To find out which you have, bring up the BBC One South and then go through the menu to the signal strength function. On that screen it usually gives the UHF channel (frequency) it is tuned to. If it's Findon, it will say channel 44 or if it's Rowridge it will say channel 24.
When automatic tuning is performed, it scans from low frequency to high. Because of the fact that Rowridge is the lowest, then a bit of a gap, then Findon, and then Whitehawk, you can prevent it from picking up the wrong transmitter by keeping the aerial lead unplugged during the scan, until it reaches the frequencies used by Whitehawk.
The automatic tuning scan goes from channel 21 to 69. Some models might give the channel number as it's being scanned.
Assuming that it's Findon that you're trying to avoid, then it uses channels 44 (BBC standard definition), 41 (ITV1, C4 etc) and 47 (HD services).
Whitehawk's lowest is C48 which is Yesterday (and other services).
Carry out one of the following:
- *If* your receiver is not a HD one, then you don't need to worry about 47 from Findon. The target is to plug the aerial in after 44 and before 48. Say at 50%.
- *If* your receiver is a HD one, then you need to avoid 47. If your receiver allows manual tuning, then don't worry about trying to get 48 during automatic tuning; manually add it once it's completed. Plug the aerial in at 59%. If, after doing this, you're missing HD services, then manually tune in to 51. And for ITV1/C4 etc it is 53 (hopefully you got the aerial in in time for that).
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John: I would agree that there are two issues.
(i) Issues with reception:
I think that the issue won't be with your aerial as you have had it replaced as I expected you might need to have done.
Is this a new problem?
Where does your aerial system serve? Does it just go to one point, e.g. the lounge, or is it split and if it is split is this a powered booster/amplifier?
If there is more than one aerial point (i.e. it serves more than one room), try connecting it to another point and tuning in the Panasonic that doesn't pick up the COMs. If there is manual tuning, then use it. Channels are COM4/SDN=C53, COM5/ArqA=C57 and COM6/ArqB=C60.
I don't think that the issue will be to weak a (COMs) signal at your aerial. At 6 miles from the transmitter, you have clear line of sight (assuming no local obstruction).
I came across this picture of Balvenie Castle and the transmitter can clearly be seen on the horizon:
Panoramio - Photo of Balvenie Castle
The image can be clicked for a high resolution one and there is no doubt that it is the television transmitter.
There is a possibility to be mindful of that the signal level being too high with the clear line of sight to the transmitter. For this reason, amplifiers should be removed if possible, if only for test/fault finding purposes.
A set-top aerial is another way of testing, it providing a lower signal level (assuming that it's sited in a suitable place).
(ii) The picture issue from the Alba is likely to be an issue with the connection between it and the TV or a problem with the output connection on the box or input connection on the TV.
There are two commonly used formats that are connected using a scart lead:
1. Composite video: This uses one conductor (wire) to carry the video. By its very nature this means that all the picture is sent down one wire (and obviously split up as necessary, as it were, at the other end).
2. RGB: This stands for "red, green, blue" and this uses a separate wire for each colour. This provides a better quality picture than composite video because it keeps the colour components separate.
The fact that you are saying that one or more colours is lost intermittently suggests that this is using RGB and that the problem is an intermittent connection with one or more of the three conductors. Perhaps try another scart lead or try connecting it to another television.
It's usually the case that TVs that have more than one scart socket on have one that accepts RGB signals and this is usually Ext1 (or AV1). So if you remove the scart plug from Ext1 on the TV and plug it in to Ext2, it may appear to solve the problem, but you will probably have just connected it using composite video.
The ghosting you see if likely to be an issue with the scart lead.
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Thursday 22 March 2012 4:27PM
neil: For lots of information and products on this, see www.aerialsandtv.com
Unfortunately, due to the channels used, it won't be possible to diplex (combine) two aerials, one for Poole's PSBs and one for Mendip COMs.
Poole PSBs are 57, 60, 53
Mendip COMs are 48, 56*, 52
* Changes to 56 on 28th March; currently on 67
Looking at Digital UK's predictions for your location (these would obviously require further investigation as to how good the signals actually are), possibilities may be:
1. All services from Rowridge - this would obviously likely only to be available to you when the COMs are on full power on 18th April. The advantage would be that it will need only a single aerial.
2. Rowridge PSBs + Mendip COMs - Rowridge PSBs will be better than its COMs, so if PSBs are OK, but COMs not, then you could get the COMs from Mendip.
3. Winterborne Stickland PSBs + Mendip COMs - *Not sure about this one* - Winterborne Stickland is another relay of Rowridge and it uses channels 40 to 46, therefore to diplex with Mendip COMs, you will need a diplexer that combines 21 to 46 and 48 to 69; I've no idea whether such a thing is available. However, be aware that near to the crossover, there will be greater attenuation.
See ATV's comments on combining two aerials:
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
In the next year or so, new licences are expected to be auctioned by Ofcom. Channel 36 is expected to be used as a Single Frequency Network across the UK and two other services are likely to start-up using channels 31 to 37 (or maybe 38, not sure).
The point is that if, for example, you use a diplexer that splits at C36, then you won't be able to receive this new service without alteration to your system.
Expect these additional services to broadcast from the sites that currently carry COM services and certainly not from PSB only transmitters.
Read the bit from ATV about aerials. Widebands have less gain at Group A frequencies, so probably best to stick to a Group A aerial for Rowridge, if you decide to go for it. This will obviously allow you to pick up new services in the 31 to 37 area when they come on air.