Blaupunkt GTI-Flex DAB3 aerial troubleshooting

[hiwakey]

I have a Clarion DAB9475R HU and live in Somerset, where DAB reception is a challenge to say the least. The passive aerial that came with the Clarion was not giving me what I needed so I tried the Autoleads DAB splitter/signal amplifier with my old rod aerial. This didn't make it any worse but didn't improve it either. After baulking at £100 + fitting for a UK Blaupunkt GTI-Flex aerial (splits FM/AM and DAB and amplifies both) I went to ze Germans and got one for £72 delivered. I've sourced the right connectors, had leads made up to suit the Clarion, had it fitted and er.... it's worse than it was before.

Does anyone know how to fault find and pinpoint what the problem might be?

Further testing since fitment, back to back with the passive aerial, has revealed that:

1) The passive aerial is not performing as well (in relative terms) as it was before, so I suspect some damage may have been done to the aerial input wire (there is a 6" pigtail on the back of the HU with an SMA connector on the end of it).

2) The new aerial, despite being mounted on the roof gives no performance gain (even in passive mode I would have expected a slight improvement) and is about the same as the old one.

3) Disconnecting and re-connecting the power supply to the powered aerial makes absolutely no difference on DAB but on FM/AM there's a noticeable difference (the sound changes). Anyone know how to find out for sure? Because DAB is either receiving or it isn’t, you can’t use change in sound to check it, all I can do is take it to an area of marginal reception and connect/disconnect the aerial power to see whether it drops out/stays on.


Hope someone can help

TIA
Mike