Television

Submitted by Peter on Tue, 2011-04-05 15:05

Television, TV, the box, are all names for the noisy distracting thing in the corner blasting noisy advertising at you because you cannot find the remote control to mute the sound. Here are some more ways to annoy yourself, family, and friends with television including TV on your computer.

I will start with a review of a USB connected DVB-T tuner for your netbook, notebook, desktop computer, and a server if you are stuck in a data centre.

Terminology

The DVB-T device, reviewed in an article listed below, introduces a few terms I will cover here.

DAB

DAB is an ancient digital radio system from the 1990s used in Europe. DAB+ replaced DAB a couple of years ago.

DAB+

DAB+ is radio broadcast within a digital format in the DVB frequency range. In effect, a television band is split into many radio bands. High quality sound uses almost half the bandwidth on DVD disks. Bluray has four times as much video with about the same audio load. Full HDTV is a step down from the bandwidth of Bluray. If all the maths works out, full quality radio would fit four radio signals in one television band. DAB+ is not full quality radio.

DAB and DAB+ share radio broadcasts in one band. Each time a new broadcast is added, all the existing broadcasts are limited to a smaller share of the bandwidth and the result is a lower quality. England was the first country with large scale DAB with the BBC in the lead. Almost immediately the DAB pool was flooded to the point where broadcasts dropped well below FM quality.

DAB+ uses a different encoding that is more efficient and DAB+ uses better error correction. The better error correction makes DAB+ sound better than DAB and FM in areas of poor reception. The better encoding is used to push twice as many stations into DAB+ than were allowed in DAB but DAB was already inferior and DAB+ is not good enough to handle twice as many stations at a similar quality. When used the way DAB and DAB+ are used in England, DAB and DAB+ are only AM quality, not FM quality.

DAB+ is offered as an open system but it uses an encoding system owned by an American company and you have to pay licensing fees in the form of extra cost when you buy anything related to DAB+.

DAB+ does have some advantages if you can stop the bandwidth flooding by greedy governments selling broadcast licences. DAB and DAB+ can work in mono or stereo, replacing the separate AM and FM systems. DAB and DAB+ can both work at FM quality although there appears to be no countries currently broadcasting at FM quality. The digital signal lets the stations add broadcasting schedules the same as the television broadcast guides included in digital TV.

DVB

DVB is Digital Video Broadcasting. Digital video broadcasting is the television equivalent of DVD and Bluray digital signals set via radio or cable. DVB-S is the satellite version. DVB-T is the terrestrial version replacing the old television broadcasting system.

DVB-S

DVB-S is the Satellite version of DVB and requires a big external antenna, usually a dish antenna, pointed direct at the broadcasting satellite. Storms can interfere. Satelite bandwidth is at a premium making satellite delivery expensive. Portable satellite reception for notebooks is not practical. Satellite is used mainly in remote areas.

DVB-T

DVB-S is the Terrestial version of DVB and uses an external antenna similar to the old analogue television. In good reception areas you can use small desktop external antennas. Some tuners have built in antennas for use in strong signal areas. When you are on the move, you want the option of an external antenna.

DVB-T uses a higher frequency range than analogue TV. In weak reception areas, use antennas designed specifically for DVB-T. The transmissions may be polarised vertically or horizontally so use an antenna designed for your region. If you are inside a metal building or a building with walls reinforced by metal mesh or a building with small windows and metal window frames, hang the antenna outside. A ten dollar antenna or USB extension cable can often give you far better results than spending hundreds of dollars on fancy tuners.

HDTV

FM radio

Remember the jump from VCR quality to DVD quality? You get a similar jump in quality going from DVD to Bluray if all your system is designed for Bluray quality. The top end Bluray quality is called 1080p. Second best is 1080i. HDTV, High Deffinition TV, is almost Bluray quality when, in Australia, labelled Full HDTV. HDTV without the full specification, is lower definition fraudulently passed of as HDTV.