All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
Mick Parsons: I have rescanned my DAB radio and Gold is now on the Yorkshire multiplex on 12A.
I can receive the "Leeds" multiplex on 12D and Ridings FM is definitely not on it, and neither is Gold. I suggest that the reason you lost Gold was because it switched multiplex.
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Matt Jordan: I can receive the "Leeds" multiplex here in the north-east suburbs of Doncaster. It comes in quite strongly on my portable DAB radio situated quite high up on the first floor.
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Leslie Pugh: "DVB-T" stands for "Digital Video Broadcasting Terrestrial"; If it is satellite you are using then you probably require DVB-S (Digital Video Broadcasting Satellite).
Freeview is the brand name of terrestrial system in the UK and its Crown Dependancies.
The "free-to-air" channels are those which you're referring to, I think.
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Richard Cullen: Sorry for not replying to your earlier message.
My comments are as a technical bod and not a professional aerial installer.
With digital reception there is quality (effectively digits intact) and strength. A receiver requires the strength to be above a certain level (the lower threshold) for it to work (providing it has a good quality signal).
I referred you to the page on the too much signal because at your close proximity to the transmitter with a high gain aerial and an amplifier you could perhaps be feeding too high a signal level into your TVs. The effect is like turning up the volume on a hifi to maximum; the sound distorts and the quality goes.
The other point to note is that the gain (sensitivity) of an aerial in one direction is at the expense of loss in others. The higher the gain the more the sensitivity is focused on a narrower beam. Thus, the higher the gain the narrower the acceptance angle:
Aerials, TV Aerial and Digital Aerial
Where there is a good path to the transmitter you can focus on the beam.
Whilst you are only 4.4 miles from the transmitter, your signal path is low to the ground for around a mile:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
This means that there may be lots of clutter in the form of buildings and trees, all of which may act to degrade the quality of the signal.
By using a high-gain aerial you have reduced your acceptance angle. So if the (average) quality over the angle which your aerial works is lower than had you used one with a wider acceptance angle then you will have a lower quality signal. It is a possibility that some object(s) have changed, such as vegetation in the signal path growing.
I think that you should try feeding the output of the aerial directly to one of the TV feeds (sockets), bypassing the amplifier and see if it improves.
There is no such thing as a "digital" aerial as aerials are designed to pick up particular frequencies and aren't bothered whether signals are analogue or digital.
All of Oxford's channels are Group C/D, so if you have an aerial that was installed during the days of four-channel analogue then it might be worth trying it.
Prior to switchover a couple of the multiplexes were down in Group A, so a C/D wouldn't have functioned as well:
Aerials, TV Aerial and Digital Aerial
That said, I wouldn't have thought that a high gain aerial was required before switchover at your location, based on the transmission powers and close proximity.
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NeilB: All transmitters are on full power, according to information available.
If you have more than one aerial whose feeds combine into one then this may be an issue. Knowledge of which transmitter(s) you are using as well as your location, preferably in the form of postcode (or nearby postcode such as that of a shop) may assist in looking up predicted signals.
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NeilB: Have you checked that your receiver is tuned to the transmitter to which your aerial faces? Which channels are affected?
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Jeannette Thonpson: Indoor aerials can be hit and miss, primarily because they rely on being in a location where they can get a good signal and indoors, with lots of obstructions (bricks and mortar and so on) in the way means that it won't be as good.
Due to your close proximity to the transmitter you may find that an indoor aerial works well. I would go for something like this:
PHILEX SLx Indoor TV Aerial: Amazon.co.uk: Electronics
Philex Indoor Digital TV Aerial Fully Flexible Caravan Motorhome Log Periodic
Mini Roof Aerial Style Labgear Set Top TV Aerial-Compact and Effective-GC
Set it with the elements flat (horizontal polarisation) and point it in the direction of Pontop Pike. Bear in mind that the best side of the house will probably be that facing the transmitter. If you're at the other side of the house then you're picking up the signal after it's passed through more walls etc. If this is for a first floor room then your chances may be greater than ground floor but that isn't to say that the latter won't work.
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sam mott: You can't use a "Freeview" receiver with a satellite dish.
If you are using an adaptor such as this then you will still not be able to use the Freeview receiver with the dish:
F Type Screw Connector Socket to RF Coax Aerial Male: Amazon.co.uk: Electronics
As jb38 says, a Freeview box is for use with a normal aerial.
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Mike Shaw: Only if the issue is that the signal level going into your receiver is dipping under the threshold it requires to work. If it's a signal quality issue then it will make no difference.
Which transmitter does your aerial face? Have you confirmed that it is tuned to that transmitter?
If you would like guidance on how to do this then say which transmitter it is and I will advise. If you don't know which transmitter it is then the direction of the aerial should allow us to work that out.
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Friday 31 May 2013 8:23PM
Mick Parsons: The comment from James Martin makes for interesting reading:
DAB agreement is a “complete shambles” : Radio Today
The Wikipedia page also hints that Ridings FM's DAB service may be pulled due to cost:
Ridings FM - Wikipedia, the free encyclopedia
I can confirm that Trax FM is still on the South Yorkshire Multiplex.