dab digital radio technology

Freeview Receivers Fail – Digital Deja Vu

World's Stupidest Freeview TV #2

Freeview is getting a pasting in the press at the moment, because a small number of set-top boxes have died after a change to the multiplex configurations. It highlights a problem faced by all digital platform operators, and challenges the notion that market forces can regulate the quality of receiver products.

The four digital TV platforms in the UK all use variants of the DVB (Digital Video Broadcasting) standard. Sky and Freesat use DVB-S* (Satellite), Virgin Media uses DVB-C (Cable) and Freeview uses DVB-T (Terrestrial). DVB-T is widely rolled out across Europe, and is the basis for Digital Television in many countries globally. DVB is to digital TV as GSM is to mobile telephony.

Both DVB and DAB are standardised in detailed standards documents published by ETSI, but like all standards, there are options and alternate configurations. All these possibilities are laid out in the standards, and both broadcasters and receiver manufacturers work from the same document to ensure that the end-to-end chain works.

Or at least, that’s the theory.

In practise, commercial pressures trump technical diligence more than manufacturers would like to admit. The standards are written in technical English, but it’s a major committment to read and really understand all the detail in the documents, and that takes time, and it’s expensive. Then the testing phase is complex, because there are so many permutations to work through to be sure that your receiver is going to work in all permissible conditions, or at least behave gracefully when it can’t support something.

Unfortunately, there is another way to develop a receiver. A scant skim-read of the spec, combined with periods of time with prototype receivers in hotel rooms, hacking away at code until the signal is correctly decoded. I know of a number of receivers that have been developed in this way – simply bashing away at code based on what’s being transmitted. As soon as the required signal comes out, the code is committed.

It’s faster and cheaper than doing it meticulously against the spec, and it allows a manufacturer to race a box out potentially earlier than rivals, and without having invested much time in tracking the development of the technology. The manufacturer just wants to shift the box, get the cash, and move the engineers onto the next consumer electronic device.

Interestingly, DAB suffered from exactly the same problem that Freeview has now, but about 9 years ago. A well-known (and at the time, best-selling) brand of DAB receiver appeared to be working perfectly until DigitalOne came on air. At the time, the BBC multiplex was broadcasting 8 services, but DigitalOne had 10. The additional number of services crashed the receiver, because the engineers at the time had assumed that 8 services would be the maximum on a multiplex. Thankfully, this was a reputable manufacturer who organised and paid for the recall and firmware upgrading of all receivers free of charge. Other receivers have been had similar limitations which have only become obvious when used in other countries, where the multiplexes are configured differently to the UK, but still entirely legitimately within the published specification.

Sky and Virgin avoid the problems that Freeview have had by supplying the receivers themselves, and testing every box themselves for compliance. It’s more costly for them, but dramatically reduces the customer-service problems that crap products create.

Because crap products tarnish the platform more than the manufacturer.

The headlines in the papers run along the lines of “FREEVIEW FIASCO“. That’s unfair. Why isn’t is saying “DAEWOO BOXES DIE” or “BUSH RECEIVERS BITE THE DUST“? Why does the Freeview platform bear the brunt of the criticism when they’re working within the spec? The Daewoo spokesman is quoted as saying “We certainly had no intention of selling boxes that would not work witin a few years”, which is hardly a robust defence. Why no unequovical statement of “Our receivers were developed according to the DVB-T specification, and tested accordingly”? What’s your view of the Daewoo, Bush, Labgear and Triax brands?

The argument from manufacturers about receiver compliance is “let the market decide”. In other words, those reputable brands who develop compliant receivers will benenfit, and people who put out rubbish will get crucified by the consumer and their brands will be trashed. Unfortunately, the Freeview problem is showing that consumers don’t react like that. They’ve already forked out their money, and their motivation was to receive the Freeview service, not necessarily to buy a cherished Daewoo product. It’s Freeview that they’re raging against.

DAB suffers from this problem. Consumers appear to assume that no matter how cheap and obviously nasty a DAB radio is, it should work perfectly, and maybe that’s a legitimate assumption. In the same way that a supermarket can’t sell you dangerously unfit food, surely they won’t sell you a digital radio that’s functionally useless. Unfortunately, it’s not the case, and there are DAB radios out there (cheap and nasty ones) which simply don’t meet the requirements of the spec, particularly in terms of sensitivity (the ability to pick up weaker signals).

Doing receiver compliance properly is a high-risk issue. Broadcasters and transmission providers are wary of running compliance programmes in case they get sued by a manufacturer if a receiver stops working. Manufacturers find it difficult to get hold of sufficient test signals to check all permutations (and that’s even the digilent ones). The risk falls disproportionately on the consumer.

The DVB / DAB logos are only supposed to be applied to receivers reaching the spec, but clearly not many people trust the manufacturers’ thoroughness in testing for these logos to carry much value any more. The logos just go on the box if it appears to work. Freeview and Freesat now run a testing programme on receivers, which grants a UK specific “tick” logo to boxes proved to be compliant. I would prefer to see a crack-down on receivers falsely applying the DVB/DAB logos, rather than developing a safety net branding. But to do so would need a significant investment in compliance testing and enforcement by DVB Form/WorldDMB, customs, importers and retailers. Is it worth it for a £15 receiver box?

Photo – my own, entitled “World’s Stupidest Freeview TV #2”.