Yet more on early NSX power antennas. I replaced the mast with the OEM one from Acura of Augusta and it worked perfectly for about a year, then went back to not fully retracting. After some searching I ran into an opinion that the clutch on the motor was likely worn. Since everything on the internet is correct, I decided to replace the entire unit, but ran into the
Groove Shark P series antenna on ebay that's advertised to work with early NSXs. It's cheap so I decide to try it, and after some messing around it works fine (so far), at least as well as the original.
It's pretty easy to install but, beyond the wire color diagram, there are zero instructions, and they did a couple of really dumb things. The motor is fixed at the bottom by a strap with holes that can be bolted to the car's existing antenna motor bracket fastener holes, but they drilled the holes with the wrong spacing to attach to both of their own motor housing mounting holes! I mickey moused that to get it to work, attached one with Locktite to hold it. The plastic pieces that come assembled to the system in the box don't work because the NSX fender hole is too small. However, they also supply a collection of different fender mounting pieces with various slopes to match the antenna's angle along with matching rubber seals. One of them is perfect for hole size and angle, except that there's a recess in the top that the nut they use to grab the top of the antenna tube tightens into. Unfortunately they don't supply a spacer to prevent the entire nut from disappearing into the recess so it can't be tightened! I used an O ring as a spacer and kind of hope it will help seal it as well. It's really stupid though, a 1 cent spacer would solve this. Of course, drilling the holes on the mounting strap with the correct spacing for their own housing would be nice too.
If anyone does this, the angle works best with the wires side of the motor facing the fender and using the mounting piece with the next to most steepest angle. What I did for the connector was cut off the connector from the original motor to keep the plug at the top, then attach some plug in crimp connectors and use the short ones on the Shark antenna. I wanted to keep all the wires as short as possible and it worked fine. Be sure everything is insulated at the connectors.
Black is ground, yellow/white is power (red shark wire), white/yellow is switched (blue shark wire).