RF Noise new VHF setup

[simonafloat]

Hi all

I posted this to the inflatable boat section

http://www.rib.net/forum/f50/new-vhf-setup-72653.html

Made a waterproof enclosure for my VHF. Inside is a gel battery and a 12v to 5v step down transformer to power the 5v GPS mouse and also give a USB charge point on the box.

However, I'm getting some interference. What I receive and what I transmit is being muted for a split second at a regular interval of approx. 2 seconds. Someone on this forum suggested the fault might lie with the 12v to 5v 'buck' converter that powers the GPS, so I disconnected it and connected the GPS to a 5v battery source instead. The interference has gone. So I'm looking for a 12v to 5v step down that won't introduce this interference. Any ideas? Apparently virtually all 'buck' converters are notorious for noise.

Many thanks

Simon

[jwalker]

Can you use a soldering iron? It's very simple to make a 1.5amp regulator, only three components are required. Just google 7805 regulator circuit and you'll find umpteen pictures of a suitable circuit.

Personally, I'd use a 0.47uF capacitor on the input and both a 0.1uF and a 10uF capacitor on the output side to suppress any noise and smooth the output. The tab is ground and needs to be heat sunk - bolt it to your radio box. The other components are so small you could possibly solder them directly to the 7805 legs so prevent having to make a circuit board but if you have a bit of vero board, so much the better.

[simonafloat]

Originally Posted by jwalker

Can you use a soldering iron? It's very simple to make a 1.5amp regulator, only three components are required. Just google 7805 regulator circuit and you'll find umpteen pictures of a suitable circuit.

Personally, I'd use a 0.47uF capacitor on the input and both a 0.1uF and a 10uF capacitor on the output side to suppress any noise and smooth the output. The tab is ground and needs to be heat sunk - bolt it to your radio box. The other components are so small you could possibly solder them directly to the 7805 legs so prevent having to make a circuit board but if you have a bit of vero board, so much the better.

Thanks, very useful. Yes, I am handy with a soldering iron. I'll have a look, cheers