Let me start by saying that Equipe Rapide Sports Car Club has been using Race America T-Link timing system for quite a few years now. Before that, ERSCC had the older, but very reliable, JAC Circuits timer but really hated having to run wires to and from the start and finish lights. And since we are in South Florida, any electrical storm instantly caused false trips everywhere! We really do like and depend on our T-Link Timing system, and with that in mind, here’s how we improved the system.
At first, the timing tent was always within say 200 feet of the start and the finish line. Regular T-Link systems are 100mW [or 0.1 Watt]. That’s not much power. Race America did realize that this was a problem, and to fix it now have systems that provide 250mW [.25W] but at the cost of battery life. Seeing that I’ve always been an Electrical Engineer first, even when working on Computers, this has always given me a serious advantage over your modern day kiddies with MSCE and MSP. To me, this was like fixing the car by adding more Engine power. I rather make the car faster using fatter tires and corner better.
Realizing that timing is usually in the middle and has to transmit in “all” directions [to start, to finish, and yes, with T-Link timers you can have a middle, or as they call it, a split time], I started to look at what we can do with the start, finish and middle timer. T-Link work using 900Mhz with Spread Spectrum [frequency hopping]. I sat down, and figured out the proper design for a Yagi antenna system that would give me over 9Db of gain. That’s like taking our 100mW and increasing it to almost 1 Watt of output power. And with the Yagi beam, it’s also removing any side talk that can interfere with the start and/or finish timer. This is like putting those blinders on a horse so the horse can only see whats in front of it and not be bother by whats around it. What I’ve found is, and this was real world use at the last Equipe Rapide Autocross was our Start Line was at one end of SunLife stadium while the Finish was a good 1/2 mile way using the Yagi Beam design. And we were at 80% or higher signal strength constantly! We had no false trips from lack of signal. In a prior event, using the regular omni-directional antenna, we could only get a signal of 20 to maybe 40%.
What I really love about this, we did not have to pay Race America for the more expensive 250mW T-Links, and that upgrade is NOT cheap, but instead for under $100 per antenna, use the current 100mW T-Link timers with the longer runtime batteries. Don’t get me wrong, if we need to time something like a 2+ mile autocross, I can see the 250mW Race America T-Links with our antenna’s doing the trick. Like I said, not a bad design Race America, just need a real engineer to improve it 🙂 .
If any other Autocross club needs help with this, contact me via email at info at the domain name above. I also found a great set of Fender Music poles to hold the antennas as well as put the Start/Finish/Middle timing boxes up in the air for even longer distances.
One last thought… As you can see from above, I bet you can guess which class I run in at SCCA events… If you picked C Prepared, your right.