Hi All,
Although I am ham radio operator, there is no show off here, but just an advise about how to solve most engine generated noise in the radios via the DC power cords.
How to know whether it is from the power cords or RF?
If RF, it mostly comes through the antenna. So disconnect the antenna, and if the noise disappears, my trick is no help. But you may try ferrite cores on the noise source.
If the noise is still there without antenna, then you probably have a power cord noise.
If you want further verification, you might also try the radio with antenna on a separate battery.
To solve this see here (pic 6 and 7):
http://www.imagestation.com/album/pi...?id=2104936060
There is a picture and a little schematic.
All what you need are 2 capacitors 103 and 2 toroid cores.
You roll each power cord (individually) around one toroid core about 5-10 turns. This will block the AC current (electric noise) but not the DC power.
Up and downstream the 2 toroids, you shortcut the 2 wires by a 103 capacitor. This will not short cut the power in DC but will shortcut the AC noise.
It works surprisingly well, but only for most power cord noise.
Hope it helps, as I just read that Palmetores also got noise whining.
Disclaimer:
I am not responsible for any consequences or if you burn/damage anything and/or do it wrong.
A solution for noise from power cords in VHF/HF radios 
