Satnav interference (Quest)

[Kritou]

I have two Quests that I run on their internal batteries. For some time now the voice commands on both units have suffered from interference that sounds like a high pitched frying noise that can, in extremis, make the audio unintelligible. The problem occurs only at high RPM and after a few minutes of engine running - it makes no difference whether the audio is routed to my UE monitor via a direct cable or through an Autocom. The Quests mount in a RAM cradle with an ACQ audio takeoff. I'm inclined to think this is an alternator rather than an ignition issue but would be interested to hear other's opinions/experiences

Garmin have no ideas other than sending the units in for repair/replacement at a cost of £87 per set

 

[RAM-man]

just to clarify,

Quest GPS is using own internal Li-on cell, ACQ is for audio out when using Quest under its own battery power .. so is the ACQ jack socket connected to a helmet headset or is it routed via autocom control box ?

 

[Kritou]

Steve - the same problem arises if the ACQ output goes direct to my helmet or via the Autocom