My experiences of swapping from Emtac to Clip-On

[Lost Cause]

I thought I might try and put Dave out of a job here and do my own semi in-depth review of the Fortuna Clip-On (certainly in terms of word count if nothing else!); pitting its performance against the Emtac BTGPS. However, I’m no expert so please don’t be too critical !

I’ve used an Emtac for the past year, and was intrigued by the Fortuna. I’ve scratched my head for a while wondering whether to swap. I liked the idea of the replaceable battery and the high sensitivity mode. So I’ve gone to the trouble of writing all this for those who may also be considering the same move.

The only two real niggles with my Emtac are that it sometimes struggles to get a fix, from a cold start, in difficult city centres conditions (e.g. London, Manchester, Bristol). It’s fine for holding a fix driving into the cities, but reluctant to get a fix when starting a journey out of the city centre. Secondly, I do a fair bit of city walking and found that I had to hold the Emtac outstretched in my hand in order to receive any satellites. With iPAQ in right hand, and Emtac held out in left hand, then I’d get lots of strange glances (I look like I’m scanning for life forms on a Star Trek away mission). Putting the Emtac in my pocket, it would then lose its fix – regardless of clearness of view. Very frustrating !

Incidentally, I ‘lost’ my first Emtac and am now on my second; both have behaved identically.

I took the plunge two days ago and here are my experiences so far.


First Fix
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After charging up the Clip-On, I then placed it on the office windowsill in ST mode and waited…. and waited… and waited… two hours later and still no fix. Switched it off, took out the battery, waited, tried again…. nothing !

Repeated that procedure and went outside for a clear view of the sky. Left it there for an hour and still no fix. Drat. I started fearing the worst.

As a last resort, I went back inside the office and switched it to the high sensitivity XT mode. Bingo ! A fix was achieved in about 30 seconds. Thank heavens for that. It then bonded immediately with my iPAQ 2210 running TTN2.24 and GPS 2.09. I used the NMEA 0183v2 38400 setting with Bluetooth COM8 and it talks perfectly to the iPAQ. No problems at all.


Driving in ST mode
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Generally speaking, while driving I’m getting a smaller quantity of satellites than with the Emtac. Usually about 1 or 2 less, but it is still holding a fix most of the time – so that’s fine.

But there is a pleasant surprise compared with the Emtac. Your position on the road appears to be updated more quickly with the Clip-On compared with the Emtac. Not that there was any major lag with the Emtac, it’s just the Clip-On appears to update you near instantaneously. Such that, when going around a roundabout, or taking a slip road, BANG, the Clip-On puts you on it immediately and tracks your progress very accurately. Uncannily so. That really took me aback, and is really cool. Very short trips up slip roads the Emtac often missed all together, but the Clip-On doesn’t miss a thing.

Driving in XT mode
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Personally, I found this a bit of a ‘no-no’. Driving round our local estate, it would often get a couple of roads ahead of itself, or behind itself. I found the whole experience very confusing – in amongst a network of roads – and so would only use the XT mode if I were desperate and couldn’t get a fix in standard mode.

Walking in XT mode
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Wow ! This gave me everything I was hoping for and more. I walked around the estate (a very non ‘urban canyon’ environment !) with the Clip-On in my pocket. For thirty minutes it held a nine satellite fix. The Emtac was in my other pocket – with no fix achieved in thirty minutes. Hence, I could walk around with just the iPAQ in my hand. The lag is not noticeable when walking. Perfect. Well, it would be if TTN2 worked properly in walking mode, but I’ll save that one for another post.

Accuracy in XT mode
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I used the Pin Distance application to test this and got some very, very interesting results.

I marked a location then, without moving, went into the measure distance mode. The display read ‘0 yards’. It didn’t flicker – it just stayed on zero. Hmmm……this meant it’s either very good or very slow. I then took three paces forward. After a two second delay it counted up ‘1,2,3 yards’. And then stayed on three yards. Hmmmm… again. Then I took a further ten paces forward and after a two second delay it counted up to 13 yards – and stayed there. I carried on up to 50 paces, after which it read 50 yards – no flickering. I walked back 20 paces and the display returned to 30 yards. I walked back to my original starting point and it read ‘0 yards’. Not 2 yards or 3 yards but ‘0 yards’. During this time I was in XT mode with a 9 satellite fix. How absolutely gobsmacking – this thing is outstandingly accurate ! I repeated the test last night with exactly the same results.

This might explain the fast and accurate performance in TTN2. I’m a 5 handicap golfer, so I’ll now be using this around the course. Using the Emtac, I’d get cumulative errors of up to 20 yards, so didn’t bother with it.

Compare this with the Emtac. After marking a location, then without moving, go into measure distance mode. It is continuously jumping between values from 0 to eleven yards, in differential mode or not. Walk ten paces and then it flickers between a display of 5 yards and 18. Go back to your original starting point and it will often try to tell you that you are ten yards away. But not the Clip-On.. oh no… this thing is almost yard perfect. In four separate tests the greatest error has been 2 yards. It’s that good, but I have no idea why.


Summary
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I’m seriously impressed. The Clip-On appears to be much faster and much more accurate than the Emtac. Walking around with it in my pocket, while in XT mode, it works where the Emtac simply doesn’t. However, the XT mode doesn’t work so well in driving where you are accelerating/braking a lot: for instance, driving round an estate. You location quickly becomes inaccurate. On the open road, it doesn’t make a great deal of difference. I haven’t tried it in a city centre yet – but sat in my coat pocket, coat in my hallway, and it still held a nine satellite fix (the same as outside). However, I still have a couple of worries which are detailed below:


Problems and curiosities
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The Clip-On can be slow to get a fix in ST mode.

This is strange because the Clip-On is seeing multiple satellites but not achieving a fix. Sat here on my desk in the office, the Clip-On can’t get a fix. It’s seeing six satellites, with all the bars over 50%, but it won’t get a fix. Not after 10mins, 30 mins, or 1 hour. But it’s never seeing less than four satellites. Jump to XT mode and it fixes within 30 seconds – same location on the desk. Meanwhile, my Emtac sat right next to it, is locked within one minute, BUT, over the course of a ten minute watch it never sees more than three satellites, and the bars at the same strength or less than the Clip-On. Isn’t that weird ! The Emtac will sometimes still hold a fix on just two in-view satellites, but not the Clip-On.

Sat in my car, with a clear view of the sky, Clip-On on dashboard, it is seeing five strong satellites but still no fix. So, I have to go outside and wait for a minute before it locks. The Clip-On seems to need a really good view of the sky before it will lock – even though it is registering four satellites or more – all above 50% strength. Pop it into XT mode and it locks immediately. In this respect, it is considerably worse at getting a lock in ST mode compared to the Emtac, even though it’s seeing more birds.

I need to do more checking on this. Right now I’m worried, because in the limited circumstances that I’ve tried it, it has regularly failed to get a fix (in ST mode) where the Emtac easily achieved a fix. Others have reported that things improve over time, so I’m reserving judgement.

Sometimes the Clip-On sporadically drops its fix even when it can see plenty of sats. In similar circumstances the Emtac was holding its fix uninterrupted.

Other curiosity is in the XT mode. At first I was very disappointed with the XT mode because it would only pull in 3-4 sats. But, all good things come to those who wait, and after letting it do its own thing for 5-6 mins (lock already quickly achieved) it slowly builds up to 8 sat readings or more; even in very difficult circumstances.

Jules

[Genie]

Thanks for your excellent review Jules.

Very informative and detailed.

[KevinL]

See the article at the link below. Fortuna has release a new version of the Clip-On using SiRF's XTrac Version 2. This new model eliminates the issues using the Clip-On while driving.

http://www.gpspassion.com/fr/articles.asp?id=90

[UHF]

Is it available yet?

[Dave]

[Lost Cause]

A quick update, after a weekend of further use:

Times to first fix are now greatly improved. It's locking on much more quickly; in largely similar times to the Emtac. So ST mode performance had improved dramitically over the first couple of days' use. No more one hour waits ! In fact, in ST mode, sat on my office desk (approx 8 feet away from the windows) it got a six sat fix this Monday morning.

So, I'm now 100% satisfied. In my system of iPAQ2210, TTN2.24 and GPS2.09 it really is working an absolute storm.

Jules

[KevinL]

As I understand, the new Fortuna Clip-On with XTrac V2 improves the XT mode so that it's nearly as good as the ST mode. It's not as accurate because it it including weaker signals, but the new firmware's fix is close enough that it can be used without the significant errors and delays that occurred with the previous XTrac release. If you have good receiption, the ST mode is best for driving.

The XT mode is best for walking, hiking, etc. where receiption may be poor. The upgraded XT mode makes it possible to effectively use your GPS when reception is poor while driving (e.g., heavy rain or snow, tree cover, city driving, etc.). Testing will determine if its feasible to leave the GPS in XT mode for all uses (driving and walking).

[matt1971]

Hi,

Using the Fortuna I wanted to add that I only ever use the Xtrac mode in the car and the only problem I have is sometimes the Co-Pilot software continues along the route for a few yards when I come to a stop at traffic lights etc.

Other than that the XT mode is excellent for driving through London.

I find the ST mode far too inaccurate when only a few satellites are visible - often reporting me on streets perhaps 100 yards away from where I am located.

Matt

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