The promised overdue summary! Sorry it's so long.
Recently one or two TV regions have had their analogue services shut down and the changeover to digital terrestrial TV (Freeview) has been made. In these areas some problems have cropped up due it seems to some set top box manufacturers not adhering strictly to the specification which they were given when DTT first started. Some of the manufacturers have said that the spec. was not specific enough but this argument will probably never be entirely resolved. From the viewers point of view in some cases their digital TV reception fails irreparably, in others it fails to receive some programmes but can be rescanned and in others a rescan removes all programmes. In the vast majority of cases TV reception continues apparently unaffected.
The main change to transmission that will affect all areas is the introduction of the Split Network Identification Table, the so-called Split NIT and this was introduced nationally last summer around July/August. It effectively enables the transmission of more channels although many have to be shared and allows more local programming than was possible originally. The NIT is used by the set top box to identify the channel and give it a name, BBC1 for instance, and also makes sure that the Electronic Program Guide or EPG displays the right information alongside its channel name. This becomes especially important if you have a digital video recorder (or PVR as they are often called) because the EPG allows you to select the programmes to be recorded at the click of the remote. And of course it would be most inconvenient if the EPG showed another channel’s programmes or times.
The effect of introducing the Split NIT varies depending on how the set top box interprets it and this in turn depends on the software/firmware being used to decode it. Some old boxes give up the ghost entirely and may not be revivable although many of the old OnDigital boxes are reported to handle it properly. Other set top boxes will report “New Channels Found” or something similar and suggest a rescan. Still others will rescan automatically and also report “New Channels” but require no action from the viewer but might have lost some channels.
The problem with rescanning is that until it is tried you don’t know if yours is one of the boxes affected adversely by the change to a Split NIT and nor how bad the problem is, and this is what Broadstairs was warning about in his initial posting. You would think that it would be a simple matter to publish a list of all affected models but, because of legal liability wrangles, that doesn’t seem to be likely to happen. (See the link to the Freeview UK site for some model numbers.) Some of the manufacturers that have had reported problems are Novapal, Daewoo, Labgear and Triax but only on some early manufactured models, but the affected models are rendered unusable by a rescan. Other manufacturers whose products may be affected include Access Devices, Sagem, Thomson and Panasonic but I’m lead to believe that over air downloads of upgraded software (OADs) will resolve their problems. This may not be possible after a rescan because the channel the update is being broadcast on may not be receivable after the rescan. Of course your initial action for any failed equipment is to return it to the seller under the Sale of Goods Act but most will require a receipt as proof of purchase and after a few years who can find receipts, but for recently bought equipment this is the way to go.
OADs are broadcast according to a schedule you can find at
http://www.dtg.org.uk/retailer/download_schedule.pl but it only covers two weeks at a time and DTG (Digital Television Group) are dependent on the respective manufacturers as to the timing of each OAD availability. This means you have to keep checking. This is not really necessary in many cases because many set top boxes automatically search for OADs that are relevant and download and apply them. I have to resort to advising you to consult your particular user’s guide/handbook for details on updating. If you discover that DTG has scheduled an OAD for your model you can force a manual update. Once again the handbook will tell you how.
My own digital recorder is a Digihome PVR80 which I bought on Ebay but which was sold initially by Argos I believe. This make together with many others were made by the Turkish company, Vestel, and rebadged. Vestel manufactured (and still does manufacture) set top boxes and PVRs for many well know names and good quality kit they are too, but they do need the latest software loaded to handle the split NITs so I’m watching the DTG schedule carefully hoping for an OAD before 25th. March when I have to do a retune because Rowridge (my local transmitter) channels are being altered. The more modern PVRs sold by Argos are equipped with the latest software and should be fine but do read your handbook about OADs. It’s always better to have the latest software and it should all happen seamlessly if you follow the handbook instructions. This may mean leaving your recorder switched to standby overnight (not “OFF”) which allows it to power up when your not using it and do its thing if it finds an OAD. Many engineers and environmentalists will find that unacceptable but it may be easier than a forced update.
I do have a fallback position in that my recorder has a serial input socket and I have downloaded the latest software .bin file and
in extremis I can update it locally but that’s more trouble than an OAD so I’m keeping my fingers crossed. I expect other PVRs have the same facility but the procedure may be different to the Digihome. PC cards for digital reception may be able to download software updates from the card manufacturer’s site.
Another change that will happen at Digital Switch Over in your area is the change to so called 8K from 2K modulation. Don’t ask what this means please! Just be grateful it is likely that all the boxes surviving up to DSO will almost certainly work with 8K if they have up to date software.
Some other links you may find helpful or interesting.
http://www.futaura.co.uk/vestel.htmlhttp://www.digitalspy.co.uk/forums/showthread.php?p=29039388 Serial port update procedure
http://www.freeview.co.uk/http://www.freeview.co.uk/freeview/Resolutions/About-Freeview-availability/Aerial-information/Transmission-changes-affecting-some-Freeview-digital-boxeshttp://www.digitaluk.co.uk/when_do_i_switch/meridian/rowridgeAs a last resort even if your prized integrated digital TV bought at some very high price at the outset of DTT turns out to be unupdateable (Is that a word?), you could purchase a set top box at a supermarket for £20 or less and connect it to your TV with a scart cable. If the TV is so old it doesn’t have a scart you can buy a box with a built in modulator that you can connect to your TV via the aerial as we did for video tape recorders. In our kitchen we have an old TV receiving DTT by this means although it will have to go when small integrated digital TVs become cheap enough. My wife isn’t keen though because you can’t store useful stuff on top of an LCD screen like you can a “proper” TV!
Tony
