Is there a commercial 12 volt to 24/28 volt DC converter out there? The 28 volts side will need 5 amps of current output. This is needed to run a 24 volt DC aircraft radio off of a 12 volt DC system.
Thanks for some help.

 

If you Google "12v to 24V converter" you will get many hits.

 

They exist, but beware that your draw on the 12v side will be roughly 12.5 Amperes. That is for a converter that's 80% efficient.

 

Have a look at this one:
http://www.wilmoreelectronics.com/Prodlit/1649_1650.pdf
The model at the bottom of the page.
Found here: http://www.wilmoreelectronics.com/Pages/Prdcts2.html
They're about $150/ea.