Remounting lapping transponder

[Bobsy SR 6]

Gents

I’m building new brake cooling ducts for my sports racer which will mount to the outside of the tub. This will necessitate remounting of the transponder which has been mounted in that area. My question is if I mount the transponder on the inside of the tub (where there is an aluminum floor) what size hole will I need to drill in the floor of the tub to allow the transponder send it’s signal to the strip imbedded in the track surface. I want to mount the face of the transponder about 1” above the inside of the floor to hopefully prevent damage from track debris impacting its face. The transponder is an AMB hard wired unit. Thoughts?

Tom

[Daryl DeArman]

Gents

I’m building new brake cooling ducts for my sports racer which will mount to the outside of the tub. This will necessitate remounting of the transponder which has been mounted in that area. My question is if I mount the transponder on the inside of the tub (where there is an aluminum floor) what size hole will I need to drill in the floor of the tub to allow the transponder send it’s signal to the strip imbedded in the track surface. I want to mount the face of the transponder about 1” above the inside of the floor to hopefully prevent damage from track debris impacting its face. The transponder is an AMB hard wired unit. Thoughts?

Tom

The farther away from the hole the larger you need to make the hole.
The closer to the track surface, the shorter period of time the loop will see your transponder signal (it doesn't need to see it long at all) but at 120+mph it may become an issue with a signal 1" wide.

Can you mount it somewhere else in the body and outside the chassis where it can see the ground without having to drill any holes in the tub? Maybe 12-18" above ground?


If you wish to protect it from possible debris the signal can see through styrofoam and fiberglass pretty easily.

[tstrong]

I had one mounted similarly about 4” above the hole in the floorpan (6” from ground). I cut a 1”x3” cutout in the pan 3” in the fore- aft direction and never had any issues. Todd

[David Clubine]

Gents

I’m building new brake cooling ducts for my sports racer which will mount to the outside of the tub. This will necessitate remounting of the transponder which has been mounted in that area. My question is if I mount the transponder on the inside of the tub (where there is an aluminum floor) what size hole will I need to drill in the floor of the tub to allow the transponder send it’s signal to the strip imbedded in the track surface. I want to mount the face of the transponder about 1” above the inside of the floor to hopefully prevent damage from track debris impacting its face. The transponder is an AMB hard wired unit. Thoughts?

Tom

I have, and others have too, run them through aluminum floors, plywood floors and frame without a hole. Currently all of my Mygales have them mounted to the front bulkhead with a honeycomb alloy crush box and a fiberglass nose covering it, no hole. Your results may vary......

[tstrong]

I have, and others have too, run them through aluminum floors, plywood floors and frame without a hole. Currently all of my Mygales have them mounted to the front bulkhead with a honeycomb alloy crush box and a fiberglass nose covering it, no hole. Your results may vary......

Interesting Dave. I never even tried shooting through the floor. I just got an estimate of the beam pattern and sized the hole to match. Can’t remember at this point where the pattern info came from. Always thought the floor .090 Al would be an issue but never tested. Todd

[Daryl DeArman]

Certainly seems to be at least somewhat dependent on how deep the loop is buried at a particular track. A bit anecdotal but some experience problems they've never had before after a track has been repaved.

As to the loop still seeing the transponder through metal. . . depends on quite a few variables. The metal definitely attenuates the signal. Whether it remains sufficient enough to read it reliably enough is up to the user to determine.

[Bobsy SR 6]

I have, and others have too, run them through aluminum floors, plywood floors and frame without a hole. Currently all of my Mygales have them mounted to the front bulkhead with a honeycomb alloy crush box and a fiberglass nose covering it, no hole. Your results may vary......

Dave

That’s very interesting. I always thought the metal would interfere with the signal. The belly pan on the tub is .90 aluminum. I was thinking about making a hole and covering the hole with a piece of plexiglass or Kydex to allow the signal to pass. I will try “shooting” the signal through the belly pan and if I have a problem I can always cut a hole later.

Thanks to all for the responses. That’s what I love about apex, the collective experience and knowledge is amazing

Tom

[bob darcey]

Tom, you may find that what works at HPR may not work at Pueblo. We had a rash of missed laps last season.