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cb750chris · 9th September 2020, 13:01

Quick question for the OP, is this the OEM radio?
I have seen a number of aftermarket radios that don't feed the radio amplifier with 12v.

The other question raised ref. USB chargers causing interference - this is (probably) because the USB chargers are mostly switched mode supplies, as this is a more efficient design - at 2Amps supply, a linear regulator would be dissipating ~18W, whereas a switched mode supply may dissipate 0.1 W - so a switched mode supply produces less heat for the same output power.
(The way these regulators work is to switch internally at high speeds - This high speed switching can cause interference that can affect the radio. [Most likely the harmonics of the switching frequency]. A different USB supply may cause interference at a different frequency and so affect the radio differently, as may changing the amount of load)

Regards
Chris

9th September 2020, 13:01	#5
cb750chris Trader Rover 75 Tourer Join Date: Apr 2011 Location: Portsmouth Posts: 849 Thanks: 201 Thanked 292 Times in 200 Posts	Quick question for the OP, is this the OEM radio? I have seen a number of aftermarket radios that don't feed the radio amplifier with 12v. The other question raised ref. USB chargers causing interference - this is (probably) because the USB chargers are mostly switched mode supplies, as this is a more efficient design - at 2Amps supply, a linear regulator would be dissipating ~18W, whereas a switched mode supply may dissipate 0.1 W - so a switched mode supply produces less heat for the same output power. (The way these regulators work is to switch internally at high speeds - This high speed switching can cause interference that can affect the radio. [Most likely the harmonics of the switching frequency]. A different USB supply may cause interference at a different frequency and so affect the radio differently, as may changing the amount of load) Regards Chris __________________ Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics.