Timex GPS Power Readings

Steele

I am looking to finally take the leap and invest in a PM, and was wondering if anybody uses the Times IM GPS for their power readings? I have one and use it with WKO for my run workouts, it also has ANT+ compatability that says it can be used with a PM for watts, cadence etc.

Thoughts?

 

Bill

 

GMAN 19030

http://www.dcrainmaker.com/2010/08/timex-ironman-gps-global-trainer-in.html ;

jkorossy

link didnt work - maybe this:

http://www.dcrainmaker.com/2010/08/timex-ironman-gps-global-trainer-in.html

i just bought same unit.

scott dinhofer

what did you folks determine with this unit? past reports as i recall is that the GPS is "jumpy"?

jkorossy

GPS is very jumpy .... even in wide open areas.  There are a few settings to tweak - something called Waas (on or off) and smoothing factor (very low, low, medium, high).   the waas settings are interesting "on" is described as 'more accurate', off is presumably a 'faster' updating.

i have not found the correct combination of settings to accurately get pacing.

i'm pretty close to returning it.

although, according to dcrainmaker, it has the same chipset as garmin -- my old garmin 305 is much more reliable ...

i really want  a unit w battery life long enough for a full IM which is why i bought it.

 

 

Steve West

Not familiar with Timex GPS but WAAS is Wide Area Augmentation Satalite or some such..... It is a pair of geosyncronous satalites above the equator that chirp out corrections for GPS systems nation wide - specifically designed for avaition - to improve location resolution. If you have it on, most of the time it is helpful.

There are all kinds of errors that can occur even with unobstructed view of the sky. Typically the best trilateration is from satalites low on the horizon - between 15* and 45* above the horizontal. Satalites over head are useless for position determination. The constelation - configuration of satalites in view - need to be dispersed around you and not clumped together in 1 quadrant. Atmospheric disterbances in the troposhpere and ionisphere cause further location degredation.

One last thing is the almanac or ephemeris data sent by the satalites and stored in the gps. A hard reset will purge the ephemeris then after about 15 minutes of data collection is rebuilt.

Not really an answer or solution - more of a general understanding of the fancy technology that goes into that thing on your wrist. Personally and professionally I only use Garmin - they are just better at what they do (unless you get into survey grade GPS units).

Steele

I have had some minor issues picking up satellite signals, but nothing that would warrant me to return it. I find it extremely useful for my running and cycling workouts, swimming..........not so much, at least the GPS function. I am not one to put the thing in a swim cap at the pool or the lake just to get a GPS signal.

Still nobody uses this for power readings?

jkorossy

@steve - thanks very informative.

@bill - i plan on using a powertap with TGT, hope to have the powertap later this week or next.  will let u know how it works.

 

[Deleted User]

I used to have a Timex GPS, but I found the pace readings so jumpy that it was basically useless. It was decent in determining my average pace and my mile splits, but not very useful in determining my instantaneous pace. I also used it for determining power while riding on my trainer for a few days while waiting for my Garmin 500 to ship, but the fact that the display was so small made it difficult/dangerous for me to use it on the road.