DAB 'interruptions' in reception

[Guest]

I have enjoyed Radio 3 on DAB for many years but I am now having reception problems which seem to fall somewhere between the tuner manufacturer and the transmitter.
My hardware is an Azur 651T tuner which has just replaced my faithful DAB500 both from Cambridge Audio. I have an outside roof aerial and a smaller outside aerial for a portable DAB radio. When I first connected the new tuner the reception was poor where it had previously been very good although it is now excellent and I suspect that the output from the Guildford transmitter has been increased coinciding with my changeover of tuners.
The fault I am trying to locate is a total loss of sound for around 3 to 5 seconds which usually happens in the mornings around 10.0am. I also get very short breaks of less than a second which is most annoying when listening to music. These problems are intermittent and seem to follow no pattern. I am now using the smaller aerial and have fitted a variable attenuator so that the signal strength is set to show a full house on the tuner. It does not sound like a poor signal as there is no ‘bubbly mud’ sound and it does not have to search again for the signal. The best description would be like somebody has switched off and then back on again.
I am reminded of my old headmaster who said that I was progressing steadily…..backwards.
Anybody else having similar problems in the Guildford area? All suggestions welcomed.
tromboni.

[Dave2002]

My use of DAB these days is largely limited to the kitchen radio, but I've not noticed any significantly unusual problems lately. The recent snow may have had an effect.

I am vaguely in your area - perhaps slightly further north.

If the times are on the hour, could the BBC be changing data rates etc. - for example from one programme to the next? I believe that DAB does allow changing the parameters as frequently as every 6 seconds, to allow broadcasters to optimise their output, but most broadcasters choose not to do in-programme parameter changes for various reasons, and only change modes at transitions from one programme to the next. If this is a factor, perhaps your new tuner can't keep up with any broadcast changes.This is, of course, mere speculation!

[johnb]

If your old tuner still works I would go back to the original set up, including the old aerial arrangement, to test whether your problem is caused by your recent changes. If the problem disappears I would then introduce one change at a time until you find the cause.

Out of curiosity, how have you introduced a variable attenuator? You are no doubt aware that impedance mismatches between the aerial/downlead/tuner can adversely affect the signal strength seen by the tuner.

[Frances_iom]

When in UK Guildford repeater is my source for FM (I can receive DAB but prefer FM) - I havn't noticed any interruptions on this - Guildford repeater with its 'rusty bolt' problems of a decade or so ago saw changes when the off-air signal into the repeater was changed to some form of direct link - I wonder if the DAB signal is an off-air repeated signal and you are hearing short breaks due to dropouts at repeater due to aircraft possibly the relatively few military aircraft/helicopters into Aldershot - on the IoM FM R3 I'm sure I hear very short (much less than 1sec) 'fill-ins' of repeated packets caused by dropouts at the IoM transmitter which I can only assume are due to such multipath cancellations

[tromboni]

When in UK Guildford repeater is my source for FM (I can receive DAB but prefer FM) - I havn't noticed any interruptions on this - Guildford repeater with its 'rusty bolt' problems of a decade or so ago saw changes when the off-air signal into the repeater was changed to some form of direct link - I wonder if the DAB signal is an off-air repeated signal and you are hearing short breaks due to dropouts at repeater due to aircraft possibly the relatively few military aircraft/helicopters into Aldershot - on the IoM FM R3 I'm sure I hear very short (much less than 1sec) 'fill-ins' of repeated packets caused by dropouts at the IoM transmitter which I can only assume are due to such multipath cancellations

This sounds like a very relevant assessment. I am not a techie but understand the basics and can apply logic to the situation. My description would be a digital signal playing catch up which sounds like we are both talking about the same thing. It's worth noting that Aldershot now have many more commercial flights - and these pass right over my house. Thanks for your input - I will make further checks!