 LAPTOP v VHF (Was laptop Problem)
Philip Allum wrote:
> Thanks to all for your comments and suggestions, particularly John,
> who came up with the answer. It WAS the laptop screen 'wot did it!'
>
> As soon as I turned it so that the screen was facing away from the
> VHF, there was no interference at all.
>
> I am also taking the inverter route to power the laptop, nominally
> 15V,
> 3.0 amps. In spite of wittering on about stabilised output in their
> literature, the transformer manufacturer immediately distanced himself
> from any idea of using it on a boat. In fairness, I did originally
> buy it for use in a car.
The voltage thru these units is stable enough in a car because if you are
sensible you rarely run a laptop with the engine running and the alternator
churning out it's voltage. In a boat it's different as you could have the
laptop on for hours with or without the engine running. The problems start
when your boat batteries get low and you start the engine. Some engineers
have reported HUGE voltages being generated for split seconds, which is all
it takes to blow your laptop apart. Also, the charging circuitry in a modern
car is miles more complex than the average yacht.
Effectively putting the voltage thru 2 capacitors, which is what you are
doing with the inverter/power brick route, at least gives you a chance to
avoid these spikes hitting the laptop's circuitry.
I have 2 Thinkpads here being used as doorstops. Both were used on yachts,
and both were powered by automobile voltage transformers. Is that a
coincidence?
Dennis.
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