Getting back to your post, you may also want to check with West Mountain Radio to see if they still sell a device intended to allow you to power 11.5 to 14 VDC radios from two different sources. You may wish to consider an extra battery for ham-radio use only and the required venting of gas produced ( yes, lead-acid batteries let loose gas that can cause an explosion ). You could charge the extra battery before travelling and not worry about becoming stranded by a dead vehicle battery. A good place to get one for you may be Acme Electronics in the Minneapolis ( Golden Valley?) area, consider a Tripp-Lite but get the model number and reviews first. BTW- Radio City is probably closed for good. You might try to contact the Golden Valley Amateur Radio Club through the 'Magic Repeater' link from the TCFM ( Twin Cities FM ) group website. They may have someone who could help you with those parts you would need. 73 from 5 land. BTW- It is now firstname.lastname@example.org so ignore the comcast.net email below.