Is DAB+ making history or going into a blind alley?

On Wednesday 25th July, Commercial Radio Australia (CRA) launched the world’s first DAB+ radio service (albeit labelled experimental) using Sir Ernest Fisk’s beloved 2CH, the once key station of the old AWA Network. 2CH switched from DAB to DAB+.

But there is only one DAB+ receiver in Australia, sitting in the office of Richard Morris, CRA’s "Digital Expert". It’s a UK Radioscape DAB+ Field Monitor dubbed by CRA’s boss Joan Warner as a "demonstration DAB+ receiver developed for the test", costing 20,850 pounds ($50,000). On the days that Richard Morris is not in his office, no-one can be listening to Digital 2CH!

There are currently no consumer DAB+ receivers in the world. PURE UK in September is releasing the Siesta clock DAB radio which will be upgradeable but the DAB+ upgrades won’t be available until next year, cost unknown.

Joan now has positioned herself as the Deputy Chairwoman, Digital Radio Committee, of the Asian Broadcasting Union hoping to convince the region’s broadcasters that DAB+ is the future of radio, to get the production quantities up so that we Australians can purchase radios cheaper than the above.

Joan’s CRA has set up a new company Digital Radio Australia Pty Ltd, using the CRA address. It’s website is:
www.digitalradioaustralia.com.au

Name supplied but withheld at the writer’s request.

Comment: this appears to be another case of bureaucracy deciding on a product regime which is available nowhere else in the world. Hence there will be very large barriers to the adoption of digital audio broadcasting in Australia. It seems like another blind alley to us.

Electrician had problems with three wires

Here in Tasmania we use lots of simple electrical heaters. When they are fixtures, we enjoy a small discount on the cost of the power they use. I have several, all installed by professional electricians.

One day, one developed a bad smell. It was never wonderful, so I decided to replace it. Oodles of shops can sell me a new heater and most have phone numbers of electricians "who can install them". However, when I rang the local electricians I got a gamut of replies, some quite original, and all equivalent to: "too busy".

The new heater stayed in the garage for a few months and I left the smelly heater turned off. As winter encroached, this became increasingly less practical. After a few more failed attempts to find an electrician willing to install a heater, I decided, "It’s not rocket science; I’ll do it myself".

When I took the cover plate off the old one, I discovered a wire curled back onto the supply cables and with its end hidden by tape. The professional electrician had connected the Active and the Neutral but hadn’t known what to do with the "extra" wire, so had used some black tape to hide it. I’d been using an unearthed heater for years.

Obviously, I am still here to write this, but as I enjoy the warmth of my heaters, I can’t help remembering that many of them have been installed by a professional electrician who when confronted by three wires and three sockets assumed that one of the sockets should be left empty and that one of the wires was a "spare" that should be taped out of the way!

I really hate to ask for "name withheld" but in this case I don’t want to alarm my insurance company unduly or to invite inspectors to visit.

Name and address withheld at writer’s request.

Comment: while we have respected your wish, perhaps it would be worthwhile to have a safety inspection, but perhaps not by a local electrician.

Tip for low-cost SLA batteries

A cost-saving method for purchasing SLA batteries is to buy from sales outlets for electric buggies (mobility aides).

My local dealer finds that many owners will upgrade their buggies for a new model. The batteries in the traded-in old model are removed and new batteries fitted before it is sold again. The old batteries are checked and any that still have a reasonable capacity are sold at $22 each (well below the new battery price around $150).

I have purchased six of these used batteries to power the rail-switching units at a local steam railway system and all batteries are still working after one year’s operation.

Dave Jeanes,
Banora Point, NSW.

Street lighting and energy wastage At a time when many people are considering various ways of saving energy and do their bit towards reducing greenhouse gases, it is disheartening to find that some government departments are obviously wasting it. One such example is street lighting. Street lighting uses relatively efficient gas vapour lamps, consuming energy at a rate of between 80W and 400W per lamp. Most street lighting in residential areas uses individual light-sensitive switches to control the lamp but it seems that some of these switches have a very wide control margin. I measured a light level of around 2500 lux at the street level which turns many of them on. That appears to be ridiculous as it causes lights to turn on as early as 4.00pm in the afternoon and sooner if there is a reasonable cloud cover. Keep in mind that the average light level within a well-lit house is usually less than 200 lux, while the light level directly under an 8W street lamp is usually less than 4 lux at ground level, after sunset of course. In one area of Liverpool, at least half the street lights were on at around 3:30pm with an ambient light level of 2500 lux measured at the street level. Surely whoever is responsible for maintaining street lighting in a particular area could do a better job of calibrating the dusk to dawn switches used in these street lights. My complaint to one such authority, Integral Energy, resulted in the answer that light sensitive switches are calibrated to the AS/NZ 1158 standard. If that is the case then someone should seriously look at the millions of watts of wasted energy and subsequent tonnes of greenhouse gases this standard causes. However, while ever these organisations are paid on the basis of maintaining street lighting and at the same time profit from the sale of energy, is it any wonder why little is done to reduce the problem? Heinz (Peter) Harle, Hinchinbrook, NSW.

Unwanted electronic hardware from deceased estate

My wife and I are currently sorting through the deceased estate of my wife’s parents. Her father was a television technician/repairmen and accumulated a lot of electronic hardware during the course of his career.

We would like to find an electronic hobbyist who can make use of this material and we are willing to give it away free of charge to such a person. The material consists of a wide range of electronic components including resistors, capacitors, valves, transformers, switches, fuses, various pieces of cabling with assorted plugs, speakers, power points, etc. Some of this material has been used but much of it is unused.

We would be interested in hearing from interested persons on (03) 9495 0092. Just ask for Sandra or Jeff.

Jeff Jeanes,
Northcote, Vic.

Lift mechanisms for LCD screens

I wish to respond to an inquiry about a lift mechanism for an LCD Screen, by M. P., of Bellarine, Vic (Ask SILICON CHIP, July 2007).

I would like to refer you to a manufacturer that specialises in such products: Linak Australia Pty Ltd, www.linak.com.au

Bob Rigor,
via email.

Technics SL1600 turntable service manual

On page 99 of the August 2007 issue of SILICON CHIP, you ask if any reader could assist with a service manual for a Technics SL1600 turntable. I found this one: www.vinylengine.com

This site is a vast repository of service manuals and user manuals for turntables: www.vinylengine.com

Franc Zabkar,
Barrack Heights, NSW.

Flashing CFLs make home like a disco

I have just moved into my newly-built house, a Queenslander-style with verandas all around. To light these I have 12 wall-mounted coach lights around the perimeter with 9W CFLs installed. Every one of them flashes randomly during the night and it looks quite like a discotheque from the roadway.

All the lights have a centralised switch (two 6-gang wall-plate switches) and then run in ‘twin Active’ cable to a 2-way switch located close to the actual light. The Neutral and Earth connections for each light are cascaded around the perimeter of the house in a separate cable.

The problem is that while the light is off (at either switch) there is always one Active (live wire) parallel to the inactive (non-live) wire in the "twin Active" cable between the two switches. The capacitance along this cable is enough to continuously trigger the start circuits in the CFLs.

I have been toying with the idea of an in-line Triac or relay between the last switch and the light to fully isolate the Active wire to the CFL, however it would have to be installed in the wall cavity behind the last switch and I don’t know what the electrical regulations requirements would be.

The only solution at present is to fit incandescent bulbs and say to hell with the energy/environment saving so the family can get a good night’s sleep. There is nothing more disturbing than a blinking light shining on you, even with your eyes shut.

Ray Hudson,
Mareeba, Qld.

Simple tank water level indicator

Inspired by your "Publisher’s Letter" and the Greenhouse Emissions article in the July 2007 issue, I was prompted (without installing a special switch) to immediately turn off our air conditioner at the meter box.

Moving on, I came to the "Tank Water Level Indicator" on page 32 of the same issue and voila! There was an opportunity to save on electrical components, construction and on-going electrical energy use, except that I had already done it! I couldn’t even submit it for "Circuit Notebook" since there was no circuit.

For those who appreciate alternative lifestyles, the "Energy Saving Tank Indicator" consists of a clear plastic pipe (13mm) attached vertically to the side of the water tank by three saddle clips using stainless self-tapping screws. The bottom end is a press-fit into a short length of clear plastic tubing which in turn is connected to some plumbing adapters to increase the diameter to match that of the tank outlet valve. One is a T-piece that goes in line between the outlet valve and the pump.

Another 70mm length of the soft plastic tubing is fitted above the full level. Into that a bolt is screwed to provide a dust-free air inlet. The bottom flexible tubing should not be looped, as it will create an airlock.

The empty to full levels – eg, 1/2, 5/8, 3/4 – can be marked on the tank next to the vertical pipe. A flat-top cap from a red biro can be cut to about 15mm and dropped into the top of the pipe as a float to highlight the water level.

This indicator is simple and 100% accurate and no access to the inside of the tank is required.

John Williamson,
Cheltenham, Vic.

Better speedo accuracy is possible but costly

I noted your comments in the August 2007 issue regarding the wide speedometer tolerances stated in the ADR’s. You may be comforted to know that none of the Australian vehicle manufacturers would accept this level of accuracy from the instrument alone. The specifications given to the instrument suppliers are tighter and always have a positive error, as correctly pointed out by one of your readers.

The act of measuring vehicle speed has a number of variables that may not be immediately obvious to most people and many mechanical variables need to be taken into consideration when applied to the various sub-groups of vehicles within a basic model type.

The fact that the drive for the speedometer, whether mechanical or electronic, is basically mechanically derived – ie, it is taken from something spinning at a fixed relationship to the road – means that all possible vehicle options have to be taken into account.

I am certainly not justifying inaccurate speedometers but pointing out that it is not all "beer and skittles". Calibration of speedometers to each individual vehicle is technically possible. The only problem is that we as consumers would not be prepared to pay the considerable extra cost, particularly for lower-priced vehicles.

Warwick Woods,
Glen Iris, Vic.

CFL promotions can be self-defeating It is interesting to read, in the media, views on energy wastage and the usually knee-jerk reactions to supposedly resolve these uninform-ed opinions! This publication has stated the same over several issues now. Sure, changing the light bulbs helps and people like myself have done this for years to save money on their energy bills. But government decisions to make this compulsory have, as you point out, not taken into account what we savers already know. Incandescent filaments in several forms need to be with us for some time yet! My local council was recently involved in a promotion to give away CFLs and energy-efficient shower heads by having stalls set up around the shopping precincts. This could have been alright except at least one location had an assistant with no understanding of how the various light fittings differed and every visitor left with wildly incorrect information! In fact, one woman went away expecting to just replace the globes in her recessed low voltage halogen units with the supplied CFLs! If the government wants to seriously conserve energy usage, they should ban all those outdoor gas heaters that the big hardware chains are promoting, along with outdoor solid fuel heaters/braziers, etc. Indeed, I saw one advertisement for an electric element device to do the same job. Running these (or any) heaters outdoors is an absolute waste, no matter what fuel source is used. Robert Graffham, Sanctuary Point, NSW.

Car speedos really are meant to read high

I read with interest the letter and the comments "Car Speedos Are Meant To Read High" in the Mailbag pages of the August 2007 issue. Having been the engineer responsible for speedos and other instruments at one of our major Australian car companies, I believe that there are some other comments and observations that need to be added.

In the first instance, cruise controls vary enormously. I have driven with cruise control since 1986 and I do a great deal of country travel. Some are easy to set and provide very close control, while others (like my latest) are hard to set and exhibit considerable overshoot.

Even so, they provide no help in close suburban driving, where attention focused on a traffic sign or adjacent traffic conditions can lead to momentarily exceeding the speed limit. Cruise controls are a help but not "a doddle".

What is of more importance is that the car manufacturers cannot control all the circumstances and must ensure that they are not in any way liable to legal action if a driver does exceed the speed limit. Hence a manufacturer will always calibrate the instrument to the "apparently faster" end of the range.

A classic example is the 4X4 I wore out and changed last year. 118km/h on the clock was a genuine 110km/h across the ground. On one of my six-hour trips, I found that I would take 30-45 minutes longer by observing the speed limits on the speedo. After wondering why this regular trip was taking so long, I found I could travel another 330,000km (in that vehicle) safely and legally by making the appropriate mental adjustments. Remember that the extra 45 minutes on that typical trip is at the least safe time – right at the end of six hours behind the wheel.

Why such a difference? It’s not an error. There are a variety of tyres that can be fitted legally and properly to the vehicle and of course, the factory tyres are the least expensive and have the smallest rolling radius. Even different brands on a sedan can produce the same effect but perhaps not to the same extent. This means that almost every vehicle on the road will show fast on the speedo.

Later in the life of that 4X4, I fitted properly specified tyres of a different brand and type and it made 5km/h difference to the speedo reading, for the same speed over the ground.

That is not all. Overhead speed indicators on highways are not free of error but they do provide a reasonable guide. The vehicle mentioned above showed 109km/h on such an indicator on the Hume Highway when heavily loaded at midnight, with the ambient temperature about 3°C and the tyres cold. At midday on a hot day, unloaded, and with hot tyres, the same speed (as per the vehicle speedo) produced 113km/h reading from the same overhead speed indicator.

If you take into account the effects of load and temperature, and the variations in tyres that can be legally fitted, this vehicle chewed up 9m/h of the allowed variation. Add in the manufacturing tolerances on the parts and then add in the "legal protection factor" for the manufacturer, and you will see that the precision of the complete system is an order less than the precision available with the instrument technology itself.

Really, we do need to keep the ADR limits. They have been established by careful people with good professional training and knowledge of the whole system, including driver behaviour, vehicle design and the law. Let us at least respect their work!

Max Williams,
Ringwood, Vic.