Mini-USb RDC-TMC and Interference

[philpugh]

Anyone using the mini-USB RDS-TMC receiver and connecting it to their car aerial?

I have had mine connected for a couple of weeks now but just noticed (this weekend) that when I tuned to an AM station I was getting huge amounts of interference. On investigation it appears to be injected by the RDS-TMC unit. I still get a good lock to the TMC service.

At present for local trips I am unplugging the unit as I am concerned about the (admittedly small) possibility of damage to my car radio.

I have tried a couple of different 12V to 5V mini-USB power supplies but I get the same interference. Everything points to the USB receiver or a totally unrelated but co-incidental earthing problem.

Final solution may have to be a separate external aerial - something I wanted to avoid.

BTW - the same setup (car/aerial/splitter etc) was used for a couple of years with my nuvi 660 without any such problems. All I did was remove the 660's TMC receiver aerial lead and connect the flying lead from the TomTom device.

More investigations this weekend with my trusty 'scope I fear!
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Phil

[G4GVB]

Is it only when you tune to a / any AM station or do you get the interference all over the AM band? Is the interference still there when you are tuned to FM?
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GO 750 LIVE v9.430 - v8.753612 EU map
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[philpugh]

All across AM band as far as I can tell.

I think it is affecting FM a little - notice a small amount of noise as if in a marginal signal area which disappears when USB connection unplugged. I suspect the interference is swamping the front end of the RF section of the radio. (It's a JVC BT-22).

I'll get a bit more serious with it this weekend. I have an oscilloscope and scanner - I'll try to see if there is any specific frequency (ies) involved. I wondered if anyone has noticed this or pehaps I have a duff TMC unit.
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Phil

[G4GVB]

It sounds like you know what you are doing, but maybe if your playing try ferrite rings.
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GO 750 LIVE v9.430 - v8.753612 EU map
XL 350 MT v9.151 - v8.75366 US Map

[philpugh]

Thanks for the tip - would have got around to that myself soon! Willlet you know how I get on.
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Phil

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