The MacAlba

I bought a cheap standard-definition digital TV set-top box (STB) about six months ago when it was “on specialâ€? at the post-christmas sales. I wanted to find out a bit more about such a thing. Once home I tried it out only to discover that the TV antenna masthead pre-amplifier kept overdriving to such an extent that the digital TV channels (only one channel removed from the analogue TV channels) were useless. I couldn’t get a strong enough signal on the digital channels because the analogue signals interfered with them.

Now, some months on, I switched the STB inline again. To my surprise it now works perfectly. I’m working on the theory that the problem is temperature related and that now, because it’s winter, there’s no cause for the pre-amp to act badly.

So, with a working STB, I began to work examine what digital TV is all about. We only currently get two TV stations transmitting digital signals in this area – ABC and SBS. The ABC is transmitting its analogue service plus its relatively new, digital only, ABC2 channel. SBS transmits its normal analogue service plus a foreign TV-news service. In addition, SBS also transmits a high-definition version of its analogue program – I can’t view this though as my STB only handles standard-definition services.

Both the ABC and SBS also transmit two radio stations. SBS relays its two analogue radio services; the ABC transmits its digital-only “Dig� and “Dig Jazz� services.

According to the STB I’m receiving the signals at about 40% of full strength – nevertheless neither the audio nor the video show signs of loss of data. We’re just under 40 km from the TV transmitter which explains the low signal strength. That and the hundreds of gum trees above the height of the TV antenna.

I suspect, however, that unless I replace the masthead pre-ampifier, I’ll experience problems again once the temperature starts to rise in 4 or 5 months time. I’ll need to research higher-quality masthead pre-amps rather than the common but cheap amplifier that was installed when the house was built a few years ago.

References:
ABC
Dig radio
Dig Jazz
SBS
Digital Broadcasting Australia