Yes, we and many other have been running dual wireless for several years.
The captain's wireless computers are set up exactly the same way as they would be on any other single bike. My SigmaSports HAC4 (high-end wireless HRM) is about 4 years old and, aside a miscalibrated temp sensor, it still works just fine. Transmitter on the left front fork leg & receiver on the bars. My wife's Polar unit -- also 4 years old -- has the transmitter sitting under the rear brake caliper on the left chain stay and the receiver sits on her handlebars. Never any cross talk with the units, although riding past high power lines will send them in RFI world for a few moments and you can't use a bar-mounted HID headlight in combination with a wireless computer.
A stoker's wireless requires one of three things:
1. It should be a different brand from the one used in front to improve your chances of avoiding RF interference issues. Polar's high-end HRMs use a technology they call "own code" that randomly locks onto one of 10 frequencies embedded in the chest strap transmitter to mitigate RF cross talk so they are always a good choice if you're running dual wireless. In fact, two Polars can be used so long as at least one of them has the own-code feature.
2. It needs to have a transmission range greater than 1m, which has limited choices in the past to the high-end Polar HRM units like my wife's S720i, Cateye's DualWireless, and more recently the sub $100 VDO wireless models. However, note that the Polar units are shipped in a mid-range configuration and the transmitter must be opened and a jumper repositioned to achieve the long-range configuration. There may now be others in the sub $100 range as it's been a while since the technology was improved.
3. It needs to eliminate the transmission range issue by using GPS technology to calculate speed, distance, etc, e.g., a Garmin 205, 305, etc... which are also a bit pricey. On the bright side, with two new models now on the market, I suspect the older models will be getting blown-out by Etailers and the second-hand market will also be flush with them, which is to say prices will be falling on the older units.
So, it really comes down to budget. Wireless is nice if you have a travel tandem that needs to be taken apart, but can get expensive if you have multiple bikes and don't want to spend the time moving the transmitters and receivers as those suckers aren't inexpensive. Wireless is also a good choice if you're already contemplating the use of a heart rate monitor (HRM). However, a $45 Cateye or Sigma wired rear-wheel unit will do everything that most users need and a strip of vinyl electrician's tape color keyed to your frame will allow you to do a pretty good job of hiding the wire if you run it along the underside of the boom tube with the speed sensor mounted just below the rear brake arms on the seat stay. If you have multiple bikes, a used Garmin 205 might be the ticket since they don't require pick-up sensors or calibration and do some other cool tricks that are only found on high-end bicycle computers.
Last edited by TandemGeek; 02-23-08 at 06:28 AM.