OK, so I made measurements like DotDun above with an ammeter directly connected. I did not make measurements without the radome connected at all, because I did not want to access the plug
and don't see the point for real usage.
Ships main batteries 13.8V and scanner set to auto
MFD8 running with radar off: 2.5A
MFD8 and DRS4D in Stdby: 1.8A
MFD8 with DRS4D at 0.0625 miles: 3.1A
MFD8 with DRS4D at 36 miles: 3.3A
MFD8 in Stdby with DRS4D operating: 2.5A
I also took measurements at house voltage of 12.6V, and all measurements are 0.3A higher.
So again, the operating radar itself is drawing 0.6-0.7A, which I assume is the motor
used for rotation, and the power used for the magnetron is already supplied in stdby.
DotDun's measurements above suggest that the total power to operate the 4KW radar is ~2A.
Greg's measurements on the 3G suggest that it draws 1.5A.
So it looks like my assertion a year ago that there was only a 0.3A actual difference between the two is pretty much correct, although a bit low. So the low power
draw of 3G is mostly marketing
that gets repeated as fact, and not an actual fact.
Am I misreading or misinterpreting something here?
As for the Furuno brochure values, these must be maximum possible values at the minimum voltages supported (10.8V?). In fact, every single
piece of instrumentation we have on board draws much less than the value sited in their specs. Our AP is spec'd at 30A, but only uses 3-5A in rough conditions.
I also like this Furuno radar (hate the chartplotter). I watch kiteboarders 1 mile away and see two returns for each - the human body and the nylon kite. This surprised me, since both are small targets with low return potential. Greater than 1 mile, I only see a single
return, but also find it surprising to get a return at all. I see Kunas in ulu's 3-4 miles away. An ulu is a 8' dugout canoe that sits 6" above the water
and is paddled by a single human. I have also watched birds fly through our radar sweep.
That is far more resolution that we need for navigating. I keep seeing the marketing pictures for 3/4G showing remarkably detailed shots of objects 30-50' away and wonder why that would be useful at all. At 50', you should not have your head
buried in a radar display. Especially at night or in fog. They never show the fast moving rain squalls at 6-12 miles (which is our major use for radar), or what a unlit fishing
boat looks like at 2-3 miles (is the higher definition helping then?).
So if the power draw difference is minimal, and the higher resolution is for pretty pictures only, what is the real advantage of 3/4G? Dockhead mentioned that he could see the shape of channel markers, but I would argue that one should not be entering a channel at all if one did not already know which markers were on which side.
I'm not knocking 3/4G - it is a valid choice, but I don't see the huge advantages (or any at all) over the other choices out there. And it does seem that Simrad has thrown huge marketing misinformation and confusion into all of this. I have yet to see a comparison of radars in a manner that matches actual navigation
usage - not even Panbo (who seems to think navigational use of his radar is for backing into his slip).