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 | Speed and Distance monitor Review - page 2 |
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| Speed and Distance monitor Review - page 2 |
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Page 2 - Technology, System Design, Features, Weight
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The Polar system uses what they call ‘coded’ transmission. This uses several 5KHz bursts of energy, and different chest straps send different combinations. Your watch locks on to the first combination it sees. So if it is getting blips from both yourself and a runner beside you, it will sort that out most of the time - although there may be brief interruptions. The footpod and the bike speed sensors have their own signature too, but unfortunately all speed sensors send the same pattern. This means that if you run next to someone else who is also using a Polar system with a footpod active, you may both see interference. ( Bear in mind that they must be really close for this to occur. )
This can also happen with the Cycling speed sensor, but it's much less likely. Polar instructs that your cycling speed sensor should be high on the front fork (within 18” of the handlebars) because it doesn’t transmit any farther. This effectively avoids crosstalk because it would be difficult for another rider to be that close for long. The footpod is a different story; since it must transmit further to reach your watch, it is somewhat more likely that a signal from a runner beside you could also reach your watch. The odds of this happening are quite small for most of us, but if your running partner already has an S625X, you might want to think about getting the Suunto to avoid that situation.
Polar’s error correction algorithms have improved over the years. In the past, running near buried power lines or an automobile would create momentary drop-outs or peaks in the data. Obviously, they can’t prevent that, but they have added a layer of heuristics that decides when the values are unreasonable, and discards them in favor of the last known good values. This is almost what you would do later in the software; essentially connect the good dots with a straight line. Most of the time, if your batteries are good, the interruption lasts a few seconds at most, and Polar’s solution is more than satisfactory.
The Suunto T6 is outfitted with a very new wireless communications link, provided by Dynastream (the same company that provides their footpod). This little company (www.dynastream.com) has developed a reputation for compelling innovation in the sports electronics field. Dynastream calls the network ANT. It is a 2.4 GHz protocol that allows multi-channel packetized communication. In other words, each sending unit (footpod, bike speed pod, chest strap) can send its own unique ID code as a part of the data message. The ANT network allows for error checking (CRC-16), full ack/nak error correction (the receiver can acknowledge to the sender that the data arrived without errors, or negative- acknowledge if not, prompting a re-send), as well as large enough data packets to allow data redundancy (sending some history each time, in case prior packets were corrupt). This is great stuff coming from Dynastream, and a number of companies are negotiating with them to license it. For more, look at www.thisisant.com. Suunto has made an excellent choice to use it in the T6. I have not been able to confirm how much of this capacity was actually used in the T6, but at the least they are using packetized IDs. Their system includes a ‘pairing’ operation that assures that the watch will only listen to a specific heart strap, foot pod or bike pod that you pair it with. Once paired, the watch will only look for that ID unless you perform a pairing again, which you would only do after replacing one of the sender units for some reason. This is enough to fend off too-close training partners or competitors. I hope to get more information from Suunto about their error correction methods; the network they use can definitely support it.
Timex uses a ‘digital’ wireless scheme. Interviews with Timex staff indicate that their system is resistant to crosstalk from other Timex chest straps as long as you are more than six feet away from the other person during the initial sync-up time. Once the watch and data recorder are locked on your chest strap, they tune out any others. This approach is simple but effective.
The Polar system consists of the watch, the chest strap, and a a footpod to provide running speed and distance data. (For cycling, you use the watch, chest strap, and bike speed sensor.) Also available for this system are a wireless bike cadence sensor and a bike power meter , which provides a wired approach to getting power, cadence and speed. The altimeter is built into the watch. The S625X watch stores your workout data. The Polar 625X can also be used while swimming, in which case you wear just the chest strap and watch to get your heart rate.
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The S1 foot pod attaches to the laces of your running shoe with a secure plastic strap. |
The Polar Speed sensor - attaches to your bike fork, and detects magnet you have attached to your spoke. |
The Suunto system is similar to the Polar system. The watch stores the workout data, and incorporates the altimeter. For running, you wear the watch, chest strap, and footpod. For cycling, you use the watch, chest strap, and bike speed sensor. Suunto does not at this time offer a cadence sensor or a power option. The Suunto watch can be worn while swimming, but the heart rate data will not transmit through the water, due to the communication protocol they used.
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| This illustration shows the Suunto footpod, as it attaches to the laces of your shoe. | The Suunto Bike pod attaches to your front hub. |
The Timex Trail Runner system is made up of: a watch, a chest strap, a GPS receiver, and optionally a storage unit called Data Recorder 2. The Data Recorder 2 is a triangular unit, about 1.5 inches per side, which hangs on your belt or shorts and listens to both the chest strap and the GPS, and stores that data for later download. If you don’t care about downloading, you can skip the Data Recorder, sold separately for $75. For recording altitude and lattitude-longitude (along with your heart rate and speed data), you need to take care that you buy the Data Recorder 2, not the original Data Recorder.
The Timex watch and the data recorder both listen to the heart rate and GPS sensors, so you get instant feedback during the workout. In addition, you may be pushing buttons on the watch to record laps and lat-long waypoints (separate things).
How do those laps and waypoints get into the Data Recorder for eventual download to the computer? They don’t. This is one obvious weakness of the Timex system. You are free, of course, to manually enter that information. Timex’ modular approach to this product springs from their understanding that the computer link option is used by a pretty small group. So to avoid adding cost to the watch, the data recording function is separate. But if you do like downloading this means one more item to wear, plus the lap and waypoint data does not get downloaded. This is a major drawback to the Timex system if you are someone who wants to record their workout and download it frequently. It means one more thing to wear (4 items) during your run, and the drawback of not having your laps integrated into your downloaded data. If you are someone who only wishes to download occasionally, this is less of an issue.
Polar has dedicated several decades to creating endurance training tools. The result is a pretty well-oiled machine. Are they letting themselves be caught from behind? Well, the S625X came out just over a year ago, and quickly established itself as the first good implementation of the footpod approach. The result of a lot of workouts and a lot of sales this past year has to be described as a nearly trouble-free product (except perhaps the cycling power option). And they continue to innovate with improvements such as the Wearlink chest strap. Sometimes they move slowly in this high-end category because they have 20 other HRM models to keep up-to-date, but they don’t often make mistakes. As far as I’m concerned, having watched Polar win over numerous challengers over the past decade, the burden of proof is on the other guys.
I have great respect for Suunto as a maker of rugged outdoor electronics. They have been world leaders in Scuba and mountaineering gear for a long time. They now bring that history with them to endurance training tools. The result is that for no good reason, when wearing the t6, I feel that it will probably still be working after the others have stopped. The one-piece high-impact plastic exudes confidence. It was designed for a user to replace the watch battery in the midst of a great adventure, and maintain water-tightness: just the battery compartment opens, not the entire back of the watch. This is all very nice, but how is it as a training tool? Did they, on the first pass, get everything right that has been a process of evolution at Polar? Perhaps, but be prepared for a few inconveniences and foibles, a shorter feature list, and less-than-friendly documentation.
Timex does not rely on this product category for its overall profitability. Nevertheless they continue to do the things that indicate a solid commitment to it. As newcomers three years ago they had the usual share of startup problems, but they have steadily worked through them and now offer a system that holds up well from start to finish.
The lead product planner at Timex described for me an epiphany that he had while driving to work, when he heard that the US government had relaxed the accuracy restrictions that had previously been placed on GPS data. In other words, the accuracy needed for sports and fitness applications would be made available to non-government entities. At that moment, he says, he saw the path that Timex should take. He did not state his goal for the program, but it was probably not to create the ultimate endurance training tool. Still, the allure of absolute accuracy in speed and distance plus altitude is pretty tempting.
Suunto’s implementation of the Dynastream footpod is slimmer and lighter (see the weight comparisons below) than Polar’s. The chest strap is traditional but comfortable and is a bit lighter than Polar’s new Wearlink. The Timex GPS unit is worn on the arm or clipped on at the waist. It is about the size and weight of an MP3 player.
Weight comparison of the various units, in ounces:
| Brand | Watch | Footpod | Chest Strap | GPS* | Data Recorder* |
| Polar | 2.1 | 2.6 | 2.2 | - | - |
| Suunto | 1.9 | 1.6 | 2.0 | - | - |
| Timex | 2.0 | - | 2.1 | 3.2 | 1.1 |
*GPS receiver and Data Recorder are components of the Timex system only.
The bottom line is this: if you go out for a run with the Polar system, you are wearing 6.9 ounces of gear. With Suunto, you have on 5.5 ounces of gear, and the Timex system weighs in at 8.4 ounces.
Although the feature list doesn't tell the whole story, it is an important part. Sometimes one particular feature will make or break the "buy decision" for a user.
To go straight to the summary of this review, click here.
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