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Letters and emails should contain complete name, address and daytime phone number. Letters to the Editor are submitted on the condition that Silicon Chip Publications Pty Ltd may edit and has the right to reproduce in electronic form and communicate these letters. This also applies to submissions to "Ask SILICON CHIP" and "Circuit Notebook".

New Freeview channel from the Seven network

Recently, the Seven network introduced channel 74, TV4ME, on the digital network. I had no problem tuning it in to all my devices but when I tried on my parents set-top box which is only 15 months old, I could tune it in but was not able to get picture or sound.

The STB is an OLIN HVBT-3200, purchased from a reputable retailer. Fortunately, on the back of the device was a hotline number, so I called it and explained the problem. The operator told me they had received a memo from the Seven network, informing them that the new channel will be broadcast using the latest MPEG4 encoding as it has excellent SD video quality for the increased video compression used. This will allow for more digital channels within the 7MHz bandwidth. Unfortunately, this particular STB does not have MPEG4 decoding and it’s only 15 months old!

This is only one device I know of but how many older units allow MPEG4? All current devices will decode HD but it’s a case of will they decode all SD? How long will it be before the other networks go this way? I understand the prices of STBs and TVs are always on the way down but if one spent good money a few years ago, especially on a TV to get HD, is it fair that we have to now consider the backward step of the appropriate SD decoder?

At home, I did a comparison recording of 7SD and 74. 74 has over three times more compression. A 3.5-minute recording from 7SD used 135MB, while the same time on 74 only used 41.5MB.

Simon Kareh,

Penshurst, NSW.

More complexity in cars is undesirable

I have just read the Mailbag letter in your January 2012 issue about mandating technological improvements in cars. The author must be dreaming. Mechanically, modern good-quality cars are extremely reliable. Unfortunately, this reliability is to a degree compromised by the complexity of electrical and computer systems.

The last thing you would want is to further reduce reliability by adding the suggested systems. The average auto-electrician can just about cope with simple electrical faults but is often completely lost on modern car computer systems.

Poul Kirk,

South Guildford, WA.

Mandating car safety features not cost-effective

Congratulations to Michael Tobin (Mailbag, January 2012) on having some ideas about road safety. But all laws which cost people money or curtail their freedoms should be evidence-based, not just someone’s idea of what might work. It’s doubly so for road-safety policies which should be determined by a scientific process; by coming up with theories then proving or disproving them with evidence that it works.

Just because someone has a driver’s licence doesn’t mean their opinions on road safety are worth anyone else listening to, as hard as it is to convince some people otherwise; common sense isn’t good enough. Road safety is engineering and lives depend on getting it right.

Road engineering also has to be cost-effective. A life is valuable but it is not infinitely valuable. So whatever is done has to generate more value in lives saved than it cost. There are a million ways that technology could reduce road deaths but most of them would cost more than they are worth, often because the scenario they are designed to prevent doesn’t actually occur very often.

You wouldn’t believe it from the
media headlines but most people, about 99%, do not die on the roads; they die of something else. Road deaths aren’t even in the top 10. So there are a million other things that could be done with the money that would save more lives.

Gordon Drennan,

Burton SA.

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