Just bought myself a new portable digital radio to replace a failing 11 year old of the same make.

The set is the Roberts stream 205 which has FM, DAB and Internet Radio tuning.

Trouble is it appears to have a couple of faults on it.

When the set is first turned on it exhibits a background audio hiss across all bands, including the internet. The hissing can flicker, rather like reception on an old radio, but, if left alone will dissappear after the set has been on half an hour or so - not sure whether the apparent disappearance of the hiss is a real effect or whether it's my auditory system screening-out the noise. The hiss is most noticeable during quiet periods during any transmission.

Interestingly, the hiss sometimes goes away if I earth the radio by gripping the case and touching some other object.

Also, power to the radio is lost when switching from battery to mains or vice versa. This occasionally results in losses of settings in the radio e.g. The set may resort to the default time zone.

This effect occurs even when the set is switched-off at its own on/off switch.

I think I have an idea what is causing these problems, but I'd like to hear others vkews.

I have to say that I was disappointed to experience these problems with a new set and one that's is priced at the beginning of the mid-range price band. Whilst the its well designed, there are aspects of the construction of this set which suggests that its designed down to a price rather than up to a quality.

Nick

Edited 5 June, 201214 yr by Clunkclick

Hi Nick,

Sorry to hear about your problems, sounds like a lemon to me.

Hope you get a replacement/refund ASAP.

I was after a DAB radio some time ago, I was really annoyed how expensive they were, especially if you wanted 2 speakers. (Why have 1 speaker/mono if you are paying for a DAB chip-set ?)

In the end I got a set from Tesco's own brand, reduced, work a treat but the display is tiny.

(Maybe your foil hat is interfering with reception ?)

Apart from the main stream channels which are already on FM, most of the rest are only broadcast in low bitrate Mono so thats why only one speaker. UK DAB sadly is a case of quantity over quality, so to squeeze more stations into limited bandwidth low bitrate and mono are the order of the day.

Is the Mono thing regional ? I see you are in Blandford, maybe the Royal Signals Base is the cause !

In the midlands I can receive loads of stations in stereo, a lot I wouldn't call main stream at all, but unique to DAB. Spoilt for choice really !

Just a few mono stations or test channels.

I think DAB is over priced and over rated in many aspects

Sounds like a leaky cap or something not filtering correctly.

Take it back and get it swapped out for a new one IMHO.

Sounds like a leaky cap or something not filtering correctly.

The hiss was only present on FM and DAB, so I thought perhaps a RF or IF frequency circuit.

I was also thinking that static being generated by a nearby air ionser was causing it, so I yesterday, I changed its location. But there was no change.

However. today the flickering hiss seems to have disapeared. There's just a very slight background hiss.

So i'm now wondering whether it was the recent stormy weather - but I wouldn't have thought that storm cloud discharge would effect DAB ?

I'll keep it under review and see what happens and make a warranty claim if necessary.

From the internet posts it looks like the power supply switching problem has a design fault at its base - no recall yet !

Since the completion of the Digital switchover last month DAB (And DTV) reception up in NW London is now very good. Its funny but on the internet radio side, I would say that its broadcast format rather than bit-rate that seems to make the difference in reception. For instance. i've found that Radio France (France Bleu) uses MP3 and listening to classical music on France Musique is a much better quality experience on this Roberts set than listening to BBC Radio 3 which uses WMA. Again, the radio set just doesn't compare, no matter what the source, with playing on the desktop - and that uses 15 year old lab tec speakers ! I got a feeling that the Realtek decoding and distribution software on the desktop is responsible for this difference. Why can't they have that in radios ?

Postscript

Just done a bit of a research. The BBC is more less alone in its use of WMA format for internet streamed radio. The only other provider I could find using that format was Vatican City radio

All the rest, including Italy, use either MP3, PLS or their own proprietry format.

Nick

Edited 6 June, 201214 yr by Clunkclick

I'd send it back I think.

A power supply design fault, will fail pre-maturely, just a case of when.

Perhaps a look at other options or just wait until they have it fixed in a product rev.

DAB is rubbish anyway. FM is better quality. I listen to either FM or Internet Radio through my Onkyo network connected Amp. It is a lot better quality due to high bitrate streaming.

I've got two DAB radios and find them perfectly acceptable.

One is a Roberts & the one I'm listening to at the moment is a Pure.

The DAB I'm listening to on the Roberts portable radio is OK, but that's only by reference to the current FM transmissions. the signal strength of which appears to have been turned down post DSO.

DAB on the portable radio is not as good as I'd thought it wouild be.

The digital radio signal I get from Crystal Palace through my terrestial tarnsmission TV , although received through an old loft mounted UHF TV aerial is much better.

Is the Digital signal I receive through my TV set a DAB signal and, if so, is itthe same one as I get on the portable radio ?

Nick

Edited 7 June, 201214 yr by Clunkclick

Sounds like a leaky cap or something not filtering correctly.

Take it back and get it swapped out for a new one IMHO.

Good advice. It sounds like it's related to the amplifier circuit ie post the Fm/Dab circuitry. Swap it I bought a Robers Solar radio for my mum a few years ago and it has been superb. Never needs a mains charge, sounds good enough for the kitchen and bathroom and the only thing needed doing to it, was to replace the rechargeables.

When the set is first turned on it exhibits a background audio hiss across all bands, including the internet. The hissing can flicker, rather like reception on an old radio, but, if left alone will dissappear after the set has been on half an hour or so

That'll be the valves warming up :p :p

As a couple of others have said: take it back......but I'd either get my money back, or a different make. If it's a batch issue, you could end up spending a lot of time in the shop listening to a load of duds.