I have recently purchased a Sony 970 and would be very pleased with it if I could get it to work correctly. The problem is that it appears (and I stress "appears") to be constantly dropping its signal meaning that when a recorded programme is played back it becomes pixellated or freezes every couple of minutes. When I first got the machine and noticed this problem, I took it back and the Sony Centre replaced it. As the replacement machine is behaving in exactly the same way, I am beginning to think I must have chosen a wrong setting somewhere. I know that it is not a problem with the aerial, the leads or the TV as I can watch the same programme via a Sony set top box without any problem. Has anybody else had this sort of problem or got any ideas on how to solve it please?

I have just purchased a HXD970 DVD/HDD recorder and I am experiencing exactly the same problems. I have checked all connections and settings and can find nothing wrong. I know my TV reception is fine as I can view Freeview through my Sony digital TV perfectly. When I compare the signal strength of the 970 with the TV the 970 is showing about 49% where the TV is showing 90% +. One specific about my problem is that it appears to be only BBC channels where the signal strength is low enough to cause picture freezing and break up. Most other channels whilst not showing as strong a signal as the TV (typically about 60%) appear to work fine. I have only had the 970 two days but I have to say I am disappointed. If the problem persists I will contact Sony. Any other users with similar experience?

Since my original post, I have tried all sorts of different arrangements to try to isolate the cause of the problem. There is now little doubt that the problem is with the digital tuner. For whatever reason, it seems as if Sony have put a rather less robust digital tuner in the 970 than they did in the set top box or the integrated TV that I have.

It's quite possible. When you look at the price of the new machine as against its predecessors, cost savings had to be made somewhere.

I found that the analogue tuners in later Sony products weren't particularly good. Owning 3 VCRs (2 Panasonic and 1 Sony) and a couple of Sony TVs, I would have to say that the tuners in the Panasonics were far superior to those in the Sony products.

Having said that, take the tuners out of the equation (I was using an external DTT box) and the performance of the VCRs was pretty comparable. I'd also say that I liked the picture quality on the Sony TVs.

Having said that, it would be a real shame if the 870 has been compromised too much by a poor quality tuner. When I saw the specification and price I did wonder if they had skimped on something, but I was still tempted to get one for the bedroom to compliment the HXD-RDR710 that's in the living room.

Once I had determined that the problem clearly lay with the built-in freeview tuner, I went to the Sony web site and posted to Sony support a query as to whether it was likely to be a general hardware problem, an isolated problem or a software problem. Does anybody have any experience as to how quickly or slowly Sony support responds to such queries?

Since posting my last message, I see that this message has appeared on the Sony Support site

"Please note: Due to unexpected high volumes of incoming enquiries, you may experience a delay in receiving our reply. We are working hard to rectify this and would like to offer our apologies for any inconvenince this delay may cause."

This seems to mean that it is anybody's guess how long a reply will take, but if there is such a volume of queries that might suggest that there is something of a problem with one or more Sony products!

Digital tuners can be rather trying sometimes. I have a Sony KD28DX51U television with a built in digital tuner.

Earlier this week in southern Hampshire we had Channel 5 and 5 Life in an unviewable condition. You could sometimes get a pixellated mess and glitching sound but that was all.
Every other freeview channel was perfect.

Fortunately, normal service has now been resumed.

Since my original posting the tuner on my machine appears to have settled down. I don't know whether it has been the change in weather but (touch wood) I have been able to record off all channels with no problems whatsoever. I can't believe the problem has magically corrected itself but so far so good.

Good. Hopefully, I can consider buying one for the bedroom in a few months (finances permitting)!

Previously I have asked SONY to specify the sensitivity of the DVB-T decoder that they use. They declined to do this saying that I didn't need to know that information.

So the value of signal strength that is actually need for "Good enough to be Good enough" remains a complete mystery.

Further the only indication they their products give for received signal level is a %

As % is a ratio of a value which remains unknown (i.e. 50% is half) then the value indicated in % doesn't tell you very much. We don't even know if it is linear!

Further a % value on one Sony product may not mean the same on another Sony product.

But perhaps your problem may actually not be related to signal level at all, but one of impulsive noise. The signal quality indication is I believe in "Real time" and perhaps you should watch this when you are experiencing picture break up which may give you an indication of a problem in that area.

Finally I have to say I have a HXD1070 which is in the same series as the HXD970 and I have a signal strength of 96% and quality of 100% and don't get picture break up.

I hope my post has been of use

I have to say that I found your post quite illuminating.

However, as someone whose technical knowledge is not wonderful, could you possibly please explain what you mean by "impulsive noise"? It's as much for my curiousity as for any practical benefit to anyone posting here!

Thanks.

A pair of electrical contacts opening (or closing) that produce a spark is producing noise. This is a very simple example but the principle is the same for say noise produced by an electric motor.

The opening of a contact is more likely to produce a spark than the closing of.

Also the opening of a contact with a DC flow is more likely to produce a spark than the same contact with the same AC flow for the simple reason that the AC current, the cycle, is passing through zero.

The noise will be of very short duration, the spark will produce a burst of energy, an impulse. This noise will pass through the air in a similar way to a radio / TV signal.

This burst of noise can find its way into the feeder cable or be received by the antenna. If this level of noise is of such an amplitude and duration that the DVB-T signal cannot be decoded than the decorder looses alighment with the received DVB-T signal and thus there can be either or both picture break up / loss of sound.

So as to try and prevent this with DVB-T it is important to use a fully screened coaxial cable.

However saying that the DVB-T signal is encoded in such a way that the "bit" order of the transmitted signal is sent in such a way that no two adjacent bits of data are sent consecutively.

Thus a burst of impulsive noise that corrupts say two consecutive bits of data in the DVB-T signal will after decoding result in the corrupted bits being seperated in the required signal.

The DVB-T protocol is designed to withstand and error correct to a degree to compensate for such bit errors. but of course a prolonged burst of noise defeats the correction that the DVB-T protocol provides.

The noise can also be "directly coupled" that is it is noise on the mains suppply and it finds its way into the DVB-T decoder from the electrical mains supply that it is connected to.

There are various methods to stop directly coupled noise. The best method is of course to suppress at source. If this is not possible that various filters can be connected into the DVB-T mains lead. If the fitting of filters proves to be insufficient than the use of a UPS may well be the only option left. The incoming mains is then rectified to DC and connected to an inverter. However at the point of this connection there will be a battery which will act as a very effective noise filter.

I hope my post has been of use

Has anyone got anywhere with this problem?

I am experiencing exactly the same and at a loss of what to do.
I bought a 970 last week from an online store, spent most of the weekend trying every combination of connection.

We have a brand new aerial that has one wire from the roof to the TV. Our Goodmans Freeview box never drops or freezes. If I bring up the Sony signal strength meter on screen it goes (strength/quality, roughly every 5 seconds) 92/100 - 92/100 - 92/100 - 0/0 (picture freezes or 'no signal') - 92/30 - 92/100 - 92/100 - 92/100 - 0/0(freezes)....

I'm frustrated as I have contacted the seller who have clearly told me that I will be charged a 20% restocking fee if they don't find a problem. Which in itself I believed was illegal under the distance selling act? But depending on who you ask it may need to be a un-opened box for a full refund. I can almost guarantee it will work perfectly if I take it back as it does appear to be something to do with the signal.

What I know:
- It's worse on certain channels such as E4
- some channels are perfect.
- My Goodmans freeview box works fine.

Although I have a cheap booster box at the TV (which I have tried with and without and makes no difference), I haven't tried a masthead booster, however if I am mostly getting 92%strength 100% quality between freezes is a booster likely to help?

I have a HXD-1070 which is the same as the HXD-970 except for the size of the harddisk.

With a signal strength of 92% and without any amplification your DVB-T signal level is really quite high and certainly doesn't appeat to need any amplification. I am wondering if your getting some overload of the DVB-T decoder from the high levels of analogue signal that will also be present (approx 17dB higher than your DVB-T signal)

You could try fitting an attenuator to see if reducing the signal level would have any effect.

Another check that you can do is tune in your TV to the channels that your DVB-T signals are being transmitted on and see if you can see an analogue picture. This may be from a distance analogue transmitter that uses the same channel as the DVB-T channel from your local transmitter. However I would expect to only see this on somthing like one of the DVB-T channels. If you can see an analogue picture then it could be either the vision or sound carrier of that analogue channel that is interferring with your DVB-T signal. Fitting an attenuator may help this.

With respect to a return to your supplier if you PM me I may have some information that could be of use to you.