I've just purchased a My Laps transponder.  There is a perfect location for it on my car, but it would require the transponder to "see" down through a layer of fibreglass.  (Specifically, the bottom of the nosecone.)  Is that likely to cause a problem?

I don't think that's an issue - mine sees through a layer of plastic & the guys on the Corvette Forum often just put it in the trunk of the car.

Cheers,
Darwin.

It uses an inductive process rather than radio waves. Needs clear path to ground with no metal between it and the track.
Fiberglass is ok.  Some liked to put it in the drivers area with a hole in the floorboard. This does not give a strong signal and gives the system problems. The unit is well build as the electronics inside the transponder are completely covered in Silicone. I have seen a few with the case pretty well mangled and still work.

Thanks, guys.  The best location for my car (a formula car) is down by the master cylinders, in front of the pedals.  There's no metal floor pan at the point, just the bottom of the fibreglass nose cone.  It sounds like that will work okay.  It'll be pointed straight down, within six inches of the track surface, so that should help, too.