I did a warm-up, a set of over/under intervals (2 minutes just under threshold, 1 minute just over, repeated three times without rest), and a cool-down, for a total of 30 minutes. The Joule recorded the PowerTap data, and Golden Cheetah recorded the virtual power. With everything set up, I hopped on the trainer, cued up a Spinervals video and some music, and started pedaling. In the Device Profile field I specified the heart rate strap and speed sensor IDs as shown. However, I found out from GC's support that you can manually specify the ANT IDs of your devices.
COMPUTRAINER AND MAC SOFTWARE
Currently, the software expects a speed/cadence sensor, and didn't like that I had a speed only sensor. Here's the article for setting things up in GC. Currently, GC also supports the Kurt Kinetic Cyclone, Cycleops Fluid 2, LeMond Revolution, and some others I'm not familiar with. Power curves are available for other trainers as well. The Garmin stick is currently available for $28.88, shipped, from these guys. In order for your computer to grab the speed from your bike and translate it to power using the Kurt Kinetic power curve, you'll need an ANT+ USB stick. To record the actual power, you'll need any ANT+ computer, such as Cycleops' Joule or any number of devices from Garmin. An ANT+ heart rate strap is very useful for training, and for this experiment, the heart rate output served to calibrate the readings for the PowerTap hub and the Kinetic Trainer, since it was common to both setups.
You'll also need any ANT+ speed (or better, speed/cadence) sensor set up on the rear wheel.
COMPUTRAINER AND MAC DOWNLOAD
Download the current build for Windows, Mac or Linux here. Setup was mostly straightforward, if you're somewhat technically inclined, and I'm sure it will be even simpler once the 3.0 version of Golden Cheetah makes it to final release. The goal was to see if people who don't have a Grover Cleveland to drop could also train with power. The new version has a greatly improved "ergo" mode, which shows real-time stats while you're doing your workout, and is comparable to pricey systems like the CompuTrainer and Tacx products. It's available for Windows, Mac and Linux. It's also my favorite software at any price I purchased the very pricey Training Peaks WKO+ software, and I don't use it any more. Golden Cheetah is open-source training software. To make the comparison, I did a set of over/under intervals using both a PowerTap hub and Kurt's power curve algorithm using Golden Cheetah's new 3.0 version. For fun, since I'm a pretty nerdy guy, I set out to see just how close this "virtual power" comes to an actual PowerTap hub that measures real power using strain gauges. Several other trainers also have a documented power curve. Additionally, that amount of power is most similar to actual road conditions compared to other trainers, according to Kurt, and I've found that to be true. That is, it takes a fixed amount of power to spin the resistance unit at a certain speed. The Kurt Kinetic Road Machine trainer has a well-documented power curve.