iQue .v. Forerunner 201 acq time.

[Bokkie]

I did an interesting experiment a few days ago. I last used either of my devices about 10 days back.

3 days back, I switched both on, outside the house, and next to each other. The iQue took about 90 seconds to get a fix. The 201 took about 45. I reckoned the iQue was more 'stale' than the 201 so after both ahd got a fix, I switch them off and tried the next day. The iQue took about 55 seconds, the 201 took about 27. I tried the same again yesterday and the times were 64 seconds (iQue) and 31 seconds (201). All things equal, I suppose the antenna is the difference but both use the same patch antenna or derivative? So the cheaper 201 seems to consistently outperform the iQue on acq?

Comments?

[si4xp]

I think the usefulness of iQue stems from its ability to do all - well almost all - that a Palm handheld does, which is quite a lot, in addition to GPS stuff, again with good integration with the addressbook. I could still live with the iQue sat acquisition time of 90 secs (normally it is about 60 secs or less) which is not a lot vis-a-vis the total driving time.

The fact that GPS has to run over the Palm OS layer might explain why a pure-play GPS would outperform iQue on sat acquisiton. Therefore, those who couldn't care less about the Palm functionality, would be better of with Garmin GPS models than iQue.

[alexcue]

si4xp, the only thing that would blow your theory about the OS is that with the Gilsson antenna i can get a fix in about 20-30 seconds (cold). So the built in antenna is what is weaker on the iQue, IMHO.

[jonasolof]

Bokkie should do the test again with an external antenna connected to the iQue to see the effect that has.

[Bokkie]

Originally posted by jonasolof
Bokkie should do the test again with an external antenna connected to the iQue to see the effect that has.

Jonas,

would that not be giving the iQue the advantage?;)

Both are patch antennas so is there something in the 201 that is 'better' than the iQue?

[Curious Cat]

Maybe the WAAS takes longer.

[sherio]

I have the FR201 too. Although I haven't done any actual comparisons, my impression is also that the FR201 does acquire satellites quicker. I don't know how patch antennas work, but this surprises me because the FR201 has such little surface area for the antenna as opposed to the iQue (does size matter?).

As suggested, it could be the WAAS enabling.

[Patch]

Quote from sherio post
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but this surprises me because the FR201 has such little surface area for the antenna as opposed to the iQue (does size matter?).
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Now that's a leading question, and i reckon that you will be getting unexpected answers from a few members, in particular C.C or Bokkie :D

[jonasolof]

Originally posted by Patch
Quote from sherio post
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but this surprises me because the FR201 has such little surface area for the antenna as opposed to the iQue (does size matter?).
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Now that's a leading question, and i reckon that you will be getting unexpected answers from a few members, in particular C.C or Bokkie :D

The actual size of the patch antenna probably matters. A patch antenna is a dipole tuned to the GPS frequency by at 1.5 GHz by its size. If I remember correctly, a GPS dipole in free air has a side of about 8 cm.

By using another dielectricum (ceramics) instead of air between the halves of the antenna, size can be reduced. To what extent reception decreases in a linear way with size I don't know.

There are other GPS receivers with patch antennas of the same size that work much better than the iQue. The Emtac Bluetooth receiver is one example. It isn't the antenna itself that you test, but the total performance of the receiver: Amplification, interference from other circuits (worse in a PDA), even the efficiency of the decoding process. So when we say that we try the antenna, we don't. Acquisition time is very dependent of having uninterrupted (no passing under trees), non mulitplied (no reflexes) signals at a low interference level ( no internal noice from circuits and processors).

By using an external preamplfied antenna it becomes obvious that the weak spot of the iQue is in the amplfier circuits for the internal antenna. I believe that Garmin chose to make a low performer, out of concern for interference from the PDA circuits and also most consumers won't notice and good circuits are more exepensive. Only, they overshot a little.

I have another Garmin with lousy reception, the 12 CX. It was sold as a de luxe series 12 GPS.

MAgellan spoiled the fun when they introduced the Sportrak and Meridian with far better performance (and a higher price). Then came the 60C and others from Garmin. However, the iQue wasn't designed for use under canopy. It is meant to guide you to Pizza Hut and the like in a low rise suburban sprawl where reception is easy. McDonald's would have loved to sell it under their own brand name with hamburger outlets and ATMs as the only POIs.

[Bokkie]

Originally posted by Patch
Quote from sherio post
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but this surprises me because the FR201 has such little surface area for the antenna as opposed to the iQue (does size matter?).
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Now that's a leading question, and i reckon that you will be getting unexpected answers from a few members, in particular C.C or Bokkie :D

Jonas has explained it as only Jonas could. There can't be too many more questions on the matter considering the depth of his answer.

Coming back to our world where the question is "does size matter?" I have a little one. But as they say "from little acorns, mighty oaks do grow!":D