Mahler9th

I just purchased my first modern data acquisition system. I considered quite a few options and had some great conversations with the folks at Veracity Racing Data and Peter Krause. I ended up with slightly used AIM EVO4/G Dash set up which is on its way from Peter Krause.

As I await its arrival, I am starting to go further with my installation plans. My car is a 1975 911. It is a race car set up for a GT class, and it has EFI. The EFI is an old Haltech system.

I searched around but could not find a lot of installation info on the web, so I thought I'd look for leads here. I know I can get all of the help and advice from those selling and installing equipment including my friends at Veracity and Peter, plus Matt and Jerry and myriad local resources. But I thought it might be helpful to first look around to see what is available on the 'net, and perhaps chronicle my journey for others.

My educational background is in electrical/biomedical engineering (advanced degree), and I have quite a bit of experience with wiring and harness design.

I want to start with planning the install for the GPS antenna. I am looking for examples, preferably pictures, and preferably Porsches.

My car has a carbon fiber roof and plastic (polycarbonate and PETG) windows, and there is a radio system antenna currently installed center rear on the roof.

ProCoach

Good article from RT on GPS antenna mounting best practices: http://www.race-technology.com/wiki/...gTheGPSAntenna

I like this: http://www.bjrsecurity.com.au/mr2/rpgpsant1.jpg

The antenna does NOT work well with carbon fiber above it.

This works fine only with fiberglass above it: http://veracitydata.com/vrd/wp-conte.../DSC_00051.jpg

jwasilko

Which Haltech ECU? I run a Platinum Sport 1000 and it works great (connected via CAN). If you have the older (E8/E11) see http://www.aim-sportline.com/downloa...V2_102_eng.pdf for setup instructions.

ProCoach

Mike's Haltech is VINTAGE!

Still runs on DOS...

Mahler9th

You guys have me laughing out loud while talking on the phone to Winders.

Yes, my Haltech is old. If one of you want to give me a known good newer one (with a working harness and a capability to communicate with modern DAQ. HW) I'd be happy to accept it. Many of my local friends have ECU's that need DOS... most are Haltechs, some are Motecs. A little bit if a challenge keeping a PC config that has working serial comm. and DOS. Challenges are often overcome as a result of motivation.

Thanks Peter. I found and reviewed the RT info before I posted, as well as the pic from the Veracity site. I think that car with a fiberglass roof was built by my friend (the guy who built my car) and was owned by several other friends. If its the car I am thinking about, it is for sale down in the LA Area.

I was pretty sure that the CF roof on my car is a no-go. I don't mind putting a hole in the roof with a grommet-- the car doesn't see rain. I think placing the antenna under the polycarb windshield or under PETG rear window could be fine, but would represent an unnecessary potential compromise with respect to optimizing satellite signal in all the places it could potentially matter.

When I searched I was quite surprised to not find a lot of install pictures, et cetera.

Wondering out loud how close Mr. GPS antenna can be to Mr. radio antenna or if it matters at all. I suppose Mr. radio antenna's large copper ground plane cannot hurt Mr. GPS antenna.

By the way, I guess I am vintage too having been a Packers fan since 1960 and starting in this hobby nearly 30 years ago.

Mahler9th

I should add that I find it interesting to note that RT sell 4 different types of GPS antennas. My presumption is that their selection is informed by experience.

linzman

I have always heard that putting the GPS antenna as far away from engine as possible was helpful. That being said, on both my 87 911 and my 968, I mounted the magnetic antenna in the back, near the radio antenna and never had a problem. In the 911, I ran the wire under the window seal at the top center and made a tiny notch in the lean and the window frame of the car, just enough for the wire to go through and still be covered by the window seal so it didn't leak. Never had an issue. Maybe you can use some of the heavy duty 3M double stick tape to hold it to the roof. In the event that it doesn't hold, which is hard to believe, it can't go far because the window seal will hold it.

Matt Romanowski

The roof is best, but you will still have great results from mounting it on the front cowl and probably good results from the rear package tray. Roger has some really good info on how the GPS works. When you know that the satellites are about 12,500 miles up and only sending out a 500 watt signal, it makes sense that the antenna needs a good view of the sky.

Also, there is a data channel that gives you the accuracy of the signal. This will help you evaluate the quality of the signal.

I've mounted mine on the front cowl and have great accuracy.

Mahler9th

Thanks guys.

My rear window set up is completely custom fabbed and there is no seal.

I vaguely recall in the past seeing some antennas mounted inside of cars like on the rear package tray and on the dash under materials like polycarbonate. I suspect that any signal compromises would relate to where a person is driving relative to positioning satellites.

I will go check out a bunch of 911s and other cars with AIM and Motec GPS next week (two great shops .5 miles from one another), so I will try to get some other ideas. If I see anything clever I will try to take some pictures and post for posterity. My default plan is a small hole with grommet on the roof near the radio antenna. I may use Velcro, Velock, double-sticky tape or similar-- I have a bunch of materials on hand that are good candidates.

Matt, can you tell me(us) who Roger is and where this information can be found?

Matt Romanowski

Roger is the AiM trainer. He has a very strong background in GPS. I believe the GPS info is in https://vimeo.com/32178690. Not sure where and I don't have time to go through the video right now to find it. It would be a great video for you to check out and get up to speed on AiM though, so I would suggest watching the whole thing.

Mahler9th

Thanks!

ProCoach

Mike, there is a difference in antennas between the makers of logging systems. I am good friends with (and a colleague of) Roger's, and he'll tell you the same as most, that the most effective placement of any GPS antenna is away from other EMI, as high on the car as possible and situated such that it can "see" AT LEAST 180 degrees of the horizon.

As one of the first "volume" users of GPS-based data acquisition and as a dealer of six different lines since 2001 that use that as a beacon substitute, a speed channel and for car position (with varying accuracy and more so, repeatability), I have found that GPS antenna placement is much more important than most haphazard DE and club level placements would indicate.

While the GPS signals can permeate polycarbonate and glass windows (as long as there aren't wires sandwiched between the glass for defrosting or metallic coverings for connectivity or sensor purposes on the late cars) as well as through fiberglass body sections, EVERY professional installation I see at the highest level of Formula and Sports Car racing has the antenna at the highest feasible point and OUTSIDE the car.

When working with Traqmate for a decade, the 3.3V active antenna (also used in R-T, R-K and MoTeC) WAS sensitive to RFI (two-way radio) antenna interference. So do put separation between the antennas for the radio and the GPS logger. The better, active and electronically equipped antennas from AiM, although introduced much later than the others, had higher accuracy, signal sensitivity and MUCH better rejection of that interference, which is why people put them on the parcel shelf or on the dash, with seemingly no ill effects.

It wasn't until I began using the RaceGrade (premium MoTeC, not the less expensive GPS-L5 and GPS-L10) and the systems relying TOTALLY on GPS calculation (Racelogic's offerings) that I began to understand how important this is. It doesn't take too long to do it right, so do it right...

jlanka

I have mine on the dashboard and it works fine.

ProCoach

And so do many. For temporary setups, I often stick it on the rear parcel shelf!

However, if you have the luxury of performing a new installation and CAN route the wire lead so that it isn't crushed or compromised, it is recommended that it go outside, that's all.

From AiM Sportline:

Mahler9th

Thanks.

I have many degrees of freedom, and as I said, my default is roof location... in the center or more toward the front. In any case away from the radio antenna just in case proximity could make the squiggly lines even squigglier, lol.

I can visit a fleet of 70's era Spec 911s next week (most with Motec), and a bunch of BMWs and Miatas with AIM to satisfy my curiosity.

All this talk about antennas makes me wonder about the SOLO and SOLO DL and how/how well they pick up satellites compared to the dash product GPS system.