Radio interferance

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Radio interferance

Postby Stovies » 13 Nov 2017, 12:29

I bought a couple of USB chargers that fit in the cigarette holder but when I use them even without anything plugged in to them then I get a very bad loss of reception from the radio.
any ideas????
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Re: Radio interferance

Postby CovKid » 13 Nov 2017, 12:37

Who made them? If generic (particularly pound shop ones), theres your answer :wink:

Bear in mind they drop 12v to 5v and the interference suppresion and smoothing can be non-existent in some.
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Re: Radio interferance

Postby bigbadbob76 » 13 Nov 2017, 19:52

yeah, probably lack of suppression in the 12v to 5v regulator, as yer man Covkid says.
Worth checking your aerial connections too, dirty aeirial connections can pick up interference.
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Re: Radio interferance

Postby AngeloEvs » 13 Nov 2017, 21:45

Most 12v USB devices are switch mode and run at high frequency, hence the interference, these are compact and do not require large heatsinks like a conventional 12v to 5v power supplies requires. I built one and it gets hot running my dash cam and sat nav but I do not get the interference.

A lot of dash cams also cause interference for the same reason where the 12v to 5v switch mode circuit is in the 12v cigar type plug.
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Re: Radio interferance

Postby Stovies » 15 Nov 2017, 14:23

I have bought 3 and the ones in my other cars work fine and don't interfere with the radio so I think it could be the way its wire up behind the dash or the radio itself
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Re: Radio interferance

Postby Mocki » 15 Nov 2017, 16:46

its alot to do with the cig socket in a t25 being fed from the same supply as the radio,
this is not the case with more modern cars
try a different feed point or moving the radio power off onto a dufferent power supply point on the fuse box

cheap china tat often has no suppression, certain led arrays are horrible to RF signals
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Re: Radio interferance

Postby itchyfeet » 15 Nov 2017, 18:39

I spent ages trying to find the reason my car radio didn't work only to find it was one of these crappy usb ciggy adapters, I assumed it was engine noise because it only happened when driving and only in low signal areas, ciggy lighter comes in with ignition
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Re: Radio interferance

Postby CovKid » 16 Nov 2017, 12:41

I'm inclined to wonder of a suppressive capacitor close to radio or back of ciggy socket might help ;)

Possible: https://www.ebay.co.uk/itm/10A-Noise-Su ... Swx2dYG1NG
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