6 volt to 12 volt inverter

[K1AJ]

I have an antique car (an old 1930 Ford) that has 6 volts POSITIVE ground for the electrical system.  I need to convert this 6 volts positive to 12 volts NEGATIVE to run a radio (OK, A CB radio) in the vehicle.  Antique car parts vendors sell these inverters for about $100!  I cannot imagine that cooking one of these up is "rocket science".

Does anyone have a cheaper source for this item or a circuit diagram of a unit I could build?

Thanks.

[WA4PTZ]

Persoanlly, I'd use a secondary 12 volt battery ,tied
or secured in the back or bed and not attach the
antenna or radio leads to the chassis.
(Magnetic antenna) The battery should last for a
long time. If you're going to be using it for several
days, take along a battery charger and charge it
overnight.  

[K5LXP]

Actually, $100 for a 6-12V isolated converter doesn't sound that bad to me.  Given that a CB doesn't draw a lot of current you probably could get away with just a battery as described above.  If you need it to be operated off the vehicle you're pretty much bound to utilizing an isolated DC-DC converter.  You might try places like Jameco, All electronics, etc to find a deal on a surplus supply.

Mark K5LXP
Albuquerque, NM
k5lxp@arrl.net

[AA4PB]

It's not rocket science, but it's a fairly complex electronic design project. Basically, you've got to convert the 6VDC to AC, put the AC thru a transformer to step it up to 12VAC, then rectify and filter it to get 12VDC. You've also got to be concerned with proper shielding and/or filtering to prevent the noise generated by the AC switching from getting into the radio. Then there's the case and connectors. If you have to purchase all the parts you probably won't save much over the $100 to purchase a ready to go unit.

[K1MNW]

Astron does or did make such a unit. I had a 6 volt Honda CB125 bike that I used it to power my 12V Heathkit mobile rig. Still have it somewhere!