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Old 04-06-2013, 14:23
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Wiz Wiz is offline
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Thumbs up Bike powered radios high power adaptor

Just found something I've been hunting for ages and so thought I'd share.

You probably know that you cannot power a high power (5 watt) radio from an Autocom as the components used inside the Autocom itself are not rated for high power use. You can usually make them work for a short while, then they burn out the voltage regulator and your Autocom starts emitting a ear-splitting scream into your lugholes.

The problem component is an IC voltage regulator (L7809) which drops the 12-14v bike input voltage to 9v, however, it is only rated at 1.5a max even with some serious heat sinking and if you transmit for longer than just a few seconds you're likely to fry it.

The obvious answer would seemingly be to buy a cheap cigar lighter battery saver for your radio from eBay and power it directly from the bike, however if you do this, you'll get terrible a crackling and popping on both transmit and receive as they are a simple resistor/coil design which causes a serious ground loop interference problems when the radio is connected to an Autocom.

So, here's finally a solution! It's a small IC made in the Philippines designed specifically to replace the L7809 with one that can deliver up to 4 amps and 35 watts! More than enough for a 5 watt radio. As it uses a IC regulator to deliver the power, they'll be no ground loop issues. It doesn't even need a heat-sink, so it could be soldered directly onto the radio or put into a cheap battery saver or old battery case.

Here's a link:

"There is no cure for birth and death - save to enjoy the interval."
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