Merc chassied van Radios

My Malvern radio reception was poor on delivery when tuned to my station of choice - BBC Radio 2. Switching off the reversing camera monitor made a slight improvement and installing a Halfords amplified internal aerial made a big improvement but there are still many areas of the UK were that station cannot be received - not a problem in my car or any previous vans.

I've spoken to several other Merc owners who have similar problems but no one has found a guaranteed solution but then none of us have been able to get at the aerial amplifier installation above the roof lining.

Peter

I am aware of several Mercedes conversion radio reception but have heard no concerns over the quality of CD audio. All I can think of is that either their is a loose connection for power or speakers or that the unit itself is faulty.

Before conversion the aerial downlead is cut and the aerial and amplifier removed from the cab. During conversion the aerial is fitted to the conversion roof and the downlead reconnected. On mine I found the reconnection was by solder joints of the inner and screen but in a manner that left some 5" of the inner exposed. There is a 12v power lead (operated by the radio on button) that folows the coax into the roof but no sign of an earth or return connection. There is no DC path between the radio end aerial connector and the aerial. I conclude that there is an amplifier installed at the aerial but it has no DC return path. I believe the exposed inner was actually the 'aerial'. Unfortunatly it was right next to the power supply for the rear view monitor and also picked up substantial interference from that. Rather that remove lockers and roof lining to get at the aerial/amplifier, I installed an internal dipole with integrated amplifier. This has minimised interference from the monitor and improved reception but it is far from perfect.

I have seen a friends downlead connection. That is connecterised but the connectors are up behind a locker and there is no slack to bring them down for examination. His radio reception is appalling all the time and I expect his amplifier is not powered and that he is not benefiting from 'exposed inner' as an aerial.

A couple of people have changed radios with no improvement and one has a thought that the Sargent power interface unit causes interference but that is not the case with my van.

It does seem that most Mercedes owners are not aware of a problem so it may be that just occasionally a power wire is not connected or it may have become disconnected up in the roof.

Time for an update.

Last year I bought a new Tomtom sat nav and found that it was also being interfered with by the 'always on' reversing camera/monitor installation so I had a switch fitted in the power feed to the camera system so that it could be switched off completely.  When off there is no problem with the sat nav or the radio (still on its Halfords internal aerial).

I am aware of another Mercedes owner who has had the camera power supply re-located and that eliminated the interference problem (but not the drop out fault that he is more concerned about) so that inspired me to experiment.

I reconnected the original Mercedes aerial and measured the current in the power feed to confirm the aerial amplifier was working.  As expected the performance was better than with the internal aerial.  The interference on weak stations is still bad and switching the monitor off with the remote control only reduces it slightly however switching the whole system off eliminates the interference completely.

At last (after 2 1/2 years I'm certain that the problem is the fact that the camera system is electrically very noisy and that mounting it above the cab internal light is a bad place to fit it.  I did have a thought that the connection to the camera that runs in the roof might be taking the interference to the proximity of the aerial but disconnecting the camera at the power supply end makes no difference

Having got used to doing it I'm happy to continue to switch the whole system off when not needed for reversing (the switch is in the dash adjacent to the gear lever).

Peter