[SECC] Need advice on car laptop DC-DC converter

[scottstraw at mindspring.com]

I too, am interested in replies on this topic.  
While the wife's 2008 Chrysler Town & Country (the designated HF mobile vehicle)  has a built-in 12VDC-120VAC inverter, my belief is that the "line lump" is also a source of extraneous RF noise. 
Would a  series of simple voltage transformers, say a 1:3 to take 12V to 36V, and a 2:1 to bring it back to 18V (or a simpler 1:1.5 to go from 12 to 18) be a feasible option?
If the power source is the battery, amperes would not seem to be a worry. Right?

Scott,
KB4KBS

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