All posts by Richard Davis
Below are all of Richard Davis's postings, with the most recent are at the bottom of the page.
trevorjharris:- Responding (rather late) to your post of three days ago, in which you said "Its only on Sky that I can see all the F1 races, the Ashes and live premiership football", I'm very glad that you can pay to get these services if that's what you want. Personally, as someone who has no interest whatever in "all the F1 races, the Ashes and live premiership football", I'm also very glad that I can get the services I want in HD without having to pay through the nose to Mr. Murdoch for the privilege!
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Brian:- It looks from the map you've published as if Brighton is still in the S Coast region as far as ITV is concerned, rather than the SE region that BBC have transferred it to. Is that correct? (You can see that I never watch ITV news!).
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Hi, Brian -
Can I, with all respect, correct an error in the terminology you use? At one point you say "Whilst the 9kHz range is fine for listening to a single human voice, it isn't very good for the dynamic range of music." In another place you talk about "...a dynamic range of 22.1kHz matching the best human ears." You've used the wrong term here - "dynamic range" means the volume range of the signal, and is measured in decibels! What you actually mean in these cases is the audio frequency response or audio frequency range.
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What Alex says would be true if the horizontal and vertical components of the signal were transmitted exactly in phase with each other. In that situation, the net result is a signal which is "slant polarised", ie.its plane of polarisation is at 45 degrees, and so you'll get the strongest signal if your receiving dipole is also at 45 deg - as Alex implies, the signal received by either a vertical or horizontal dipole will be 3dB lower in strength. However, this assumes that the dipole is offset from the horizontal or vertical by 45 degrees in the same direction as the radiation produced by the transmitter (eg clockwise) - if you offset it by 45 deg in the other direction (eg anticlockwise) you'll get nothing! Thus you're still in the situation where the received signal strength varies with the orientation of the receiving aerial.
To get round this, most BBC transmitter sites (certainly all the main ones and also many of the low power repeaters) use an aerial configuration which produces circular polarisation. This is acheived by delaying the feed to one section of the aerial relaive to the other so that the horizontal and vertical components are 90 deg out of phase with each other, resulting in a signal whose plane of polarisation rotates, making one 360 deg rotation per cycle. This means that a dipole aerial with any orientation (horizontal, vertical or slant at any angle) will receive the same signal strength. That strength, however, will be 3dB less than would be received by a dipole receiving a plane polarised trnsmission of the same power so, as KMJ says, the present 250kW transmitters are giving approximately the same effective signal strength as the 120kW horizontally polarised ones they replaced.
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Hi, Roberta,
It sounds as if a pirate radio station may have opened up from a location very close to you. Unfortunately, if this is the case it's difficult to deal with, as the pirate station certainly won't reveal their location, and won't care in the least that they're causing you problems! The thing to do in the first instance is to check with your neighbours and see whether they also have problems, which seems quite likely. You can then put in a complaint to The Radio & Television Investigation Service via their website at Radio & Television Investigation Service - hopefully, they will be prepared to investigate for you and, if you're lucky, close the pirate down. However, a quicker though more expensive solution would be to buy a DAB radio. They're now quite cheap - the transmissions they receive are on a completely different waveband from FM, so won't suffer the interference you're getting, and the sound quality is almost as good as FM, certainly better than LW. As a bonus, you'll be able to get additional stations, such as Radio 4 extra.
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Monday 29 July 2013 12:11PM
Richard Miller:- If, as you say, you're getting a perfect picture but can't record, the problem can't possibly be with the signal strength as that would affect the live picture as well - the problem must be a faulty box. The present day incarnation of the Bush trade mark, I'm afraid, has nothing to do with the distingushed radio and TV manufacturer who used to trade under that name, but went out of business due to the hare-brained policies of a certain former Prime Minister. It's just a comapny who've bought the brand name and now buy in products from other companies and stick their name on them. It's no wonder their Customer Services department doesn't know what it's talking about! You'd be better off demanding a refund, (as you're entitled to do if the product isn't fit for purpose - you don't have to accept a replacement) and buying a box from a more reputable manufacturer such as Humax!