Hi Bob,
Thank you for the rundown on the AIS options. The current draw quoted for the NASA Clipper AIS is only 50 mA, while the current draw for the VHF/AIS combo from Standard Hoizon is quoted at 0.55 A on standby. therefore, if relying on the AIS and one has to leave the VHF on, the current draw would be 10 x as much. do you keep the VHF on most of the time? mostly off? if you keep the VHF off, the lower current draw of the stand alone unit is a significant advantage.
Thank you,
Todd