All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Nick: This page, also from Megalithia (the website that does the prediction for how good your line of sight is):
Mo' Betta - abuse of DTT TV booster amplifiers
Boosters should be fitted before loss:
- before a length of cable whose loss is too great for the signal to stand (this may be useful where there is a good quality but low amplitude signal), or;
- before a signal is split (so as to counteract the loss of splitting the signal).
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Dominic: At such close proximity to the high power transmitter, I think that your receiver may be being overloaded:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
Try something that will pick up less signal and see if the problem goes away or at least subsides. A set-top aerial maybe. An aerial lead on its own may pick up enough signal; you may have to move it about to best effect.
Or if the plug on your aerial lead is a screwed together one, remove the outer part and put the inner pin into socket.
You may need quite a bit of attenuation. A 20dB variable attenuator may not be enough. Perhaps a high value fixed, e.g. 24dB in conjunction with a 20dB variable will give you enough attenuation whilst allowing you to fine tune.
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Nick: I have just found this Arqiva document on a prospective Suffolk DAB multiplex which does list Aldeburgh:
http://stakeholders.ofcom….pdf
Thinking about the intended coverage area of the Suffolk multiplex (Suffolk!), *relatively* speaking the area left out (uncovered) if Aldeburgh wasn't used would be greater (relatively) than with the national multiplex.
There are more Digital One transmitters coming on air. I know that Scarborough was added a few years back. Due to the terrain, the only reliable transmitter for TV and radio is its own.
I have to say though Nick, from what I can see, you aren't in a valley of which there are a few in the area and of which I assume those living in will have no option but to rely on Aldeburgh. For that reason, I get the feeling that, whilst it is unfair that there are those who cannot get commercial/independent DAB stations, you may be in an area where you can. And if you add to that the fact that you intend to receive at roof level, then your chances must be even greater!
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Terry Ward: Combine Divis and Calbeck signals. You ain't gonna do it!
Why do you want Caldbeck anyway, when Divis is a full service transmitter?
You need a diplexer such as these:
Online TV Splitters, Amps & Diplexers sales
You need one which splits the two at a workable channel.
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Robin Burnett: Whilst line-of-sight is of course the best, such a high power transmitter can still be effective (and not require a booster) over the brow of a hill.
It is possible that the signal strength from your aerial into your amplifier is too high for the amp to cope with. This means that all outputs will be distorted and no level of attenuation on the inputs to the TVs will repair this bad signal.
The purpose of the booster is presumably to provide equal signal levels at each aerial socket.
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Terry Ward: I'm not sure of how much spacing there needs to be between digital channels.
There are a number of issues you really need to be aware of before you start:
1. You really need filters or a diplexer to combine the aerial feeds which you can't use because of Divis and Caldbeck both being Group A.
2. Calbeck broadcasts two variants of the Public Service Channels (English and Scottish), both of which are ITV Border and not STV. Scottish broadcasts reportedly use directional antennas, unsurprisingly in the direction of Scotland.
3. All of Calbeck's nine channels have negative offsets. I have read where all those transmitters that use C30 have a negative offset. So I assume that reason for them all needing negative offsets is because all neighbouring channels from 22 through to 30 are used by Caldbeck. Perhaps one of the experts could confirm that digital broadcasts can be on adjacent channels. Also, that a positive offset on C22, for example, means that if C23 is to be used, then it must also have a positive offset.
I like a challenge too, but would it not be easier to receive ITV1 HD from Isle of Man?!
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Terry Ward: Having looked at this page:
TV regions overview map | ukfree.tv - independent free digital TV advice
I suggest that Port St Mary, which is Group B may be the best. At 2kW it is the most powerful transmitter on the island.
The only caution I would give is that the powers that be won't release the radition pattern so the projection by this website of its coverage assumes an omnidirectional antenna has been used.
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Nick: It depends on where you are, but it could be too much signal:
Freeview signals: too much of a good thing is bad for you | ukfree.tv - independent free digital TV advice
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Den: Could you get Freeview before switchover?
I see that the Bembridge area is quite well served by the Brading relay transmitter which does not carry the Commercial channels such as Yesterday. I wonder if this is a general indication of difficulty receiving directly from Rowridge in some parts of that area.
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Thursday 26 April 2012 11:04PM
Rob Godwin: If your aerial is pointing south and the elements are vertical (up/down), then it is facing Tavistock transmitter which does not carry these services. You have therefore been receiving those channels from another transmitter (probably Caradon Hill) and therefore the solution to reliable reception is to replace your current aerial with on on Caradon which is due west. For Caradon, aerials are horizontal (elements flat).
Have you been along this road and had an aerial on Caradon fitted?