Digital television - a complete failure?

I could not let the Publishers Letter in the July 2003 issue pass without comment. Your headline was at best a bit harsh and a few facts are just a little wide of the mark. Your dire prediction of a paucity of television services beyond 2008 is unfounded.

When digital TV started in Metropolitan areas on 1 January 2001, 2008 was selected as the earliest possible date for analog closure in these areas. In light of the uncertainty of how the digital TV rollout would progress, this date was made subject to a review in 2005. In regional areas of Australia where DTTB is currently being rolled out the earliest possible analog termination is 2012, with this date also subject to review.

Initially, all DTTB services will carry standard definition (SDTV) programming which is a wide screen version of the analog service. In quality terms (technical quality that is!), SDTV is at least equal to the best that DVD offers. And the story only gets better as broadcasters introduce HDTV versions of programs. I'm sure your judgment that current SDTV offerings are "low-quality digital signals" has no support among the growing number of digital TV viewers.

If I hark back to the DVD analogy for a moment, we have seen a rapid and significant reduction in the cost of these units over recent months. I believe we are on the edge of a similar slope with digital TV decoder pricing. A quick check of the Digital Broadcast Australia website (www.dba.org.au) shows a range of decoders priced from as low as $299 each.

Decoder availability and pricing is subject to chicken and egg syndrome - Australian broadcasters realise this and are aggressively rolling out digital services. And as more digital services become available, demand is growing.

There is much good news in the digital TV story. Australia leads the world in its introduction of free-to-air terrestrial digital TV broadcasting and is increasingly becoming the reference for many other countries on the brink of embracing this technology. We have taken the analog system beyond what was intended with innovations such as stereo audio, teletext and captioning. Like the vinyl record, B&W TV and analog mobile phones, analog TV has gone as far as it can go - it's time to open a new door.

Is Digital TV a complete failure as you suggest? Only to the extent that a newborn baby is a complete failure to create a fully developed adult.

Raoul Prideaux,
Director of Engineering and Technology,
Southern Cross Broadcasting (Australia) Ltd.

Set top boxes not foolproof

The "Publisher's Letter" in the July 2003 issue, on the failure of Digital TV to attract more viewers, is mostly correct, except for the price of a Standard Definition STB. There are boxes available from chain stores for under $300. I think Galaxy as the first Pay-TV entity proved that you can't afford to give away a product and expect loyalty from the customer. Just because it's cheap does not make it a good buy!

There are many reasons why the idea has not been embraced, unlike VCRs, mobile phones, etc. Firstly, no one thought about the end user. The Pay-TV companies didn't want multi-views or multi-channels; that would be "free" defacto Pay TV with options not available to them. The FTA broadcasters didn't like the idea of Standard Definition; heavens to be if someone else started up a competitive FTA station using the spectrum the government could have sold off from the analog spectrum.

If you already receive good quality reception, why change? There is no incentive to switch networks unless your TV pictures are poor. There is no guarantee your recent purchase of a STB will work. Because I know from hundreds of hours of experience that unless you can find THE SPOT for the receive antenna, one or more channels refuse to lock in.

The price of a reasonable BER (Bit Error Rate) digital meter is still too high and I rely on my knowledge of antennas and reception theory to get me through the installation. BER is more important in digital transmissions than signal level, as a high signal strength does not necessarily mean a clean signal. The lower the BER, the less prone to dropouts the system will be. I cannot stress enough that Digital is not necessarily a "Plug and Play" item, as promoted by the DBA and retailers.

As a consumer, I don't need Digital to get quality pictures at my abode. But I would embrace the technology if I could get extra features, particularly Dolby 5.1 sound to take advantage of a home theatre scenario. I am more than impressed by the quality of SD pictures and in experiments with a SD/HD box on a quality projector system capable of matching the HD standard of the box, there is little difference to be seen.

Where to now? Senator Alston needs to stop thrashing around and accept the fact that the ABC dropped multi- channelling due to lack of viewers, and allow the commercial stations to multi-channel now; at the very least they could afford to do it. He could also stop protecting the Pay TV operators from competition, which will lead to an improvement in the quality of programming for everyone.

The take-up and disconnection rate for Pay TV shows customer discontent and I can't see more than 10-15% of the population ever embracing the service. PAY-TV has prospered in areas of poor or no FTA reception because there is no competition. These companies have treated their customers and installers with contempt and do not deserve any protectionist legislation.

The Broadcasters need to give the viewing public at least 5.1 Home Theatre sound on all SD transmissions when the program allows, and keep HD for when the technology becomes affordable. There were times I swear that Channel 7 Digital was transmitting in mono, because my amplifier didn't decode in Pro-Logic.

Digital is a great solution to poor reception areas that currently have or will receive upgraded analog to digital signals. But has the government considered the fringe analog dwellers, who have at best a "fortuitous reception" because they reside in the middle of nowhere. Will they have the gumption to switch of analog signals in 2008 before giving the viewers more choice and viable reasons to change?

Brian Andrews,
Bestek Communications Pty Ltd,
Steels Creek, Vic.

Digital TV has a lot to offer

In reference to the Publisher's Letter appearing the July 2003 issue of SILICON CHIP, I find myself in the strange position of defending digital television. For a person whom is highly critical of the government for not providing the extra funds to allow Fly and Kids to be a success, or allow the commercial networks to multi-channel, I strongly feel that digital TV has a lot to offer.

First, let me point out that there are now several standard definition set top boxes available which sell for slightly less than $300. Secondly, there are a number of standard definition wide-screen sets selling for less than $2000 and even a 76cm high definition Samsung wide-screen set appearing with a street value of around $2100.

I am one of the lucky (or foolish) people to spend $3100 on a 76cm Panasonic HD ready set and DGTEC HD STB ($700) and am now enjoying some of the HD broadcasts which are starting to appear. But I would also like to point out that most of the new standard definition programming is now being made in wide-screen, looks fantastic, and requires at least a standard definition box to enjoy in its full glory.

John Serra,
via email.

PIC programmers soon to be a thing of the past?

I just want to raise a point since I haven't seen it mentioned in the pages of SILICON CHIP yet: will PIC programmers (the hardware) be a thing of the past soon? I'm just beginning to get into PICs myself and I've been doing lots of reading about them so far. One thing I'm been trying to decide on is what sort of programmer should I buy/build. There are quite a few of them out there and in the July 2003 issue there is yet another programmer!

Which is all rather confusing for me. More so since I read about how simple it is to program a PIC and it can be done in circuit via a simple ICSP (In-Circuit Serial Programming) cable. This seems the better method to use so after digging around on the net I came across these web sites:

"The 16F628: Why the 16F84 is now obsolete."

David Tait's web page

Byron A. Jeff's page "Why the 16f84 is now obsolete" is a very interesting read and I thank him for pointing me in the right direction.

David Tait's FPP software package contains a very simple programmer plus schematics for making various interfaces. I made the "TOPIC2" interface and it worked straight away. WOW! I can program PICs! Got a LED to flash on RB0 of a 16F628. But I wasn't fussed on connecting directly to the parallel port as they are notoriously unreliable so I modified the TOPIC2 by adding an old 74LS05 as a buffer. But the 74LS05 is an inverter! No problem. The FPP software has a setup option where you can invert the various signals that it generates or receives which corrects the problem. You can even select which parallel pins are used!

So I'm having fun programming my 16F628 with my home made ICSP cable. I crammed everything into the shell of the D25 plug and terminated the other end with a standard header that can be used on any future circuits I build. The 74LS05 is powered from the PIC's power supply. The PIC does not have to be disconnected from the rest of the circuit for as soon as the cable is plugged in, it is ready for programming as the /MCLR pin is pulled low. Once programmed, the cable is unplugged and the PIC immediately springs to life.

This is probably all old news to everyone else but I'm just a newbie trying get started somewhere. I don't intend to ever build an all-singing hardware programmer. Can't see the point of it.

David Vieritz,
Mango Hill, Qld.

Comment: you are right of course but there is still a place for PIC programmers.

CD piracy and copyright

The issue of CD piracy and copyright is in the news headlines again. What I can't understand is that one of the biggest whinges is coming from a company that on one hand is in the recording industry and on the other hand manufactures the NET MD which allows the user to connect its Mini Disc recorder to a PC and download up to 320 minutes of MP3 music files that have been sourced from the Internet.

Even their last TV commercial showed a man pulling up in a drive-through in his 'Doof mobile', ordering his favourite music, then off to the collection window where he is handed over a brown paper bag. Out of the bag he removes a mini disc with his ordered music. Nowhere in that commercial was it mentioned the music was royalty-free or that it is illegal to copy music.

I don't have a PC but I can copy audio CDs with my Philips CD audio recorder. It can also be used to create CDs from any audio source; ie, vinyl, cassette, microphone, etc. I can't use normal CD-Rs; they have to be branded CD-R AUDIO. Price wise, in comparison to brand name CD-Rs sold with jewel cases, they cost about 20% more. This is obviously due to the royalty factor that has been included which makes it legal for me to copy my copyrighted audio. I don't mind paying around $1.50 per 80-minute CD, because it is cheap compared to a $4 - $5 chrome cassette.

Like CD-R Audio, royalty fees are also imposed on audio cassettes and on Mini Disc. What annoys me is I can use any of these media to legally copy vinyl, cassettes and CDs that I have purchased, but the recording industry is still getting a cut from the royalties if the media is used for anything other than that; eg, recording a meeting. They can't have it both ways.

Now the industry is playing with the idea of copy protection on CDs. Are they planning on dropping all royalty fees on the recording media?

Simon Kareh,
via email.

Computer power supply cases

Nowadays, many computer system units are being discarded as useless. But one item is quite useful: the power supply case. It is a well-made metal box and, after the PC board is removed, it can be used for many electronic projects. It even has a fixed power plug and a fan, if needed. Don't forget to save the screws and grommets, too.

Jim Jacobs,
Engadine, NSW.

Modern lighting offers plenty of choice

I read the June 2003 editorial and I agree that the currently popular 12V halogen lamps are not very efficient in this day and age. They are still basically an incandescent light source plus the added losses from inefficient transformers. At first glance, they are to many people very appealing and relatively cheap to install - but not necessarily to run. They often present an impressive "showcase" look to a room, hence their popularity. Some lighting consultants will correctly advise that many display homes (featuring halogens) are over-lit. Lots of "attractive spots" with many dark separating patches.

And as for the transformers - efficiency could be a lot better but at a cost. Too many buyers ignore this aspect, choosing only on purchase price, not the true cost-of-ownership price (including running and other consequential costs such as heat removal). There is insufficient awareness hence lack of demand for better products (such as electronic transformers which are at least double the purchase price).

240V halogens are available except only a very limited range. I am not sure about their efficiencies (lumens/watt) but suspect they are significantly less than 12V halogens (offsetting their advantages) as they appear to be running at lower filament temperatures, given the expected manufacturing difficulty of a higher voltage (lighter gauge) filament and its inherent fragility. Another problem is that 240V lamps do not benefit from the current limiting effect of the transformer at start-up. Inrush at start-up presents the highest stresses to a filament from the magnetic forces of the high inrush current (up to more than 10 times the run current).

Despite all the negatives, halogens certainly have their benefits and uses. They are very compact and due to the virtual point-source of the filament, are ideal for efficient beam focusing in a compact housing. They are a very effective choice where spots or focused coverage is required - with very little off-beam wastage (compared to other lamps & luminaires) and offer near-perfect colour rendition (continuous spectrum white light).

They are more efficient than conventional incandescents but nowhere near the efficiency of fluorescents or compact fluorescents (CFLs) in terms of total light output (spherically) from electrical input. Fluorescent light sources are more efficient energy converters but halogens are more efficient optically. And compared with GLS (standard incandescent), halogens are both electrically and optically more efficient. If wide coverage is needed (such as from a bare light bulb) - a CFL is the obvious choice.

It would be a mistake to give the impression that halogens are all bad and waste power. How often have we seen conventional fluorescent fittings or CFLs plugged into inappropriate fittings wasting most of the energy where a better focused light source is required? The real issue is that we all need to pay more attention to our lighting requirements and appropriately design for each room or application. There is no single universal lamp type, technology or luminaire that is the answer to every location.

We need to consider many factors such as (not necessarily in any priority order) what lighting levels are required over what coverage area, power efficiency, heat output, lamp life/cost, safety, lighting effect, dimmable or not, controls (including timers, sensors, ballasts and transformers), colour rendering and glare control, etc.

The range of CFLs now available at continually falling prices is fantastic. Similarly with halogens, the range is immense (linear, bare lamp & reflector lamps with beam widths of 10 - 60 degrees) benefiting from substantial ongoing development, while the traditional GLS bulb hasn't significantly changed at all in almost 100 years.

New tri-phosphor "T5" fluorescent lamps are raising the bar even higher, especially with electronic ballasts. Their narrower diameter permits smaller housings with superior optical performance. Unfortunately, the technical advice and range of fittings commonly sold through retail lighting shops can be limited. A bit of further research through the vast amount of information available on many lighting industry websites, especially for commercial products, can be most helpful.

I would like to encourage you to consider some articles on lighting and the various technologies to help raise awareness and technical knowledge amongst your technical readership. Your editorial was a great start, hopefully encouraging many readers to give their lighting more thought rather than assuming a few 12V halogen down-lights are all that is required.

The key to saving energy is improved design from a better technical understanding of the issues, enabling an informed selection of appropriate lamps and fittings. Any energy saved is money in the bank with reduced greenhouse gases, while improved lighting design will be more comfortable to live or work in.

Murray Nielson,
via email.

Comment: we ran a comprehensive series on electric lighting some years ago.

Switched capacitor fan speed control

The speed control for the ceiling fan, referred to in "Ask Silicon Chip" on page 90 of the September 2003 issue, may be a switched capacitor type, as these are usually encapsulated. They switch one of two capacitors in series with the motor and the third position is a straight-through connection.

The fault may be in the capacitor for the low speed setting but I have found on many occasions the fault lies with the deterioration of the capacitor in the fan itself. This affects the speed of the fan on all settings of the controller but is most noticeable on the slow setting. These capacitors exist in a very hot environment and probably dry out in time.

Barry Hubble,
via email.