Navman Sleeve (Quick Fix) AntiStatic bag

egslav8r

Thanks for that Onbashi.

I am still waiting for my antistatic bags to arrive.

I have installed Gps info and move the unit closer to the screen using my Ram mounts.

On the journey home last night I had aquisistion in 1 min 20 secs.

Max satellites was 10, Min 3, average probably 7 or 8. Average signal strength 41.

Is this good or bad???

Re-aquisition times seem to be around a minute(interestingly I did a back to back test with my Garmin GPS90, it took 3 minutes to aquire 6 satellites this morning, the Navman acquired 8 in 1 min 20, Both lost their dsignals under the Tesco canopy when I stopped for fuel BUT the Garmin re-aquired in 10 secs and the navman took 30 secs!).

What the minimum no of satellites the Navman needs for continuous Navigation?? And what sort of signal strength is considered to be Good or Normal.

I may already have a sort of rerad. I used a Lowe GPS amplifier with my Garmin some time ago. This possibly could loop to the Navman via the PC mobile battery box.

onbashi

I would be curious to see how that works, from the knowledge I have gathered Electomagnetic Interference (EMI) doesnt cause any known problems with the navman sleeve, but it may be worth a try, what you must bear in mind is that it may allow Interference to pass through depending on the range of RFI (dB's) produced from the ipaq and what range the paint can actually block.

Ideally sending the RFI to ground is the best option as it eliminates all of the RFI without allowing any to get through, I'm currently working on a device that slips between the ipaq and sleeve that has a thin coiled cable on it that has a crocadile clip on the end of which you connect to any metal work in the vehicle, I'll let you all know how it goes...
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ipaq3870

I've briefly tried 4 layers of the anti-static material and, indeed, it does seem to improve TTFF figures.

Another alternative / additional solution might be to internally treat the Navman case with a zinc based EMI spray? Unfortunately I don't have any to hand and at 20 quid a can it's a bit pricey to try (although a can would treat quite a few units).

Perhaps someone with an RS/Farnell account at work could try it?

onbashi

The problems you are suffering from are almost definately caused by the athermic windscreen you have, all is not lost, you can purchase a re-rad antenna from any decent gps stockist, just stick the receiver on the roof of your vehicle, power it up and keep the end close to your ipaq. You can tell if you need a re-rad by getting a fix inside the vehicle and then moving it outside checking the amount of sats in view on both occasions, if its much greater outside then yes you need one.

The GRIB will be available in two choices to suit either the 206mhz cpu or the 400mhz cpu, the reason why is because the 400mhz cpu although not fully utilised in ppc 2002 causes a higher RFI than a 206mhz cpu, unfortunately a GRIB designed for a 400mhz cpu will not block RFI from a 206mhz cpu and vice versa due to the different level of decebels of interference, i.e.lower decebels of interference can pass through materials designed for higher decebels of interference. Confusing, I know, its taken me 3 weeks to get my brain around!. I'm not sure how much the initial cost will be as of yet but it could be as low as aproximately £7

Hope i've helped,

Darren, those pics and that article would be great!
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onbashi

how can i tell how many db's of noise is being emmited from the ipaq, because if its under 90db the best material to use is aparently aluminium foil.

I think i'm going to suggest my idea to navman for some proper testing.

sheild the interference, fix the problem hmmm!

It cant be impossible to sheild frequencies on small electronic devices, because it's being done all the time on cctv camera's with sensitive circuitry, ie you will always find a thin piece of aluminium or copper between the psu and the signal processor if you remove it you get hard to see tiny hum bars (lines) on the picture, i know i've just tested it as i'm a cctv engineer, on some camera's its sheilded by the aluminium heat sink on the psu or at least i think so, because there seems to be no other material seperating the two. This I believe makes it possible to experiment with diferent material for the ipaq, my testing begins today!, but I am happy with the anti-static trick

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In The Land Of The Blind The One Eyed Man Is King!

onbashi

Carl, i'm glad that it has worked well for you, the improvements are shocking if you generally have a weak receiver like mine.

sfi1, thats a good way of testing the foil, never thought of that, thanks

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In The Land Of The Blind The One Eyed Man Is King!

sfi1

I'd have thought that the foil would be better. Maybe it's the thickness of the material that makes a diference. The anti static bag that I used was a 3M Moisture barrier bag that I got with an IBM drive in. A quick check i did on the bag was to put a mobile in it and watched the signal bar go from 4 down to 1.

carl

Attaching an aluminum foil to the back of my Ipaq 3660 using adhesive tape reduces TTFF to less than a minute! That´s a great improvement - I just can´t believe that Navman har overlooked such a simple fix.

Thanks Onbashi for a great tip!

onbashi

I'm glad you've noticed a small difference, any difference is a good thing, i've been using it for some time now and so far i've been getting fixes a lot quicker, always less than a minute, always!. I tried aluminium tape and for some strange reason doesnt work as good as anti-static foil hmmm I might try weaved aluminium if I can get hold of some
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In The Land Of The Blind The One Eyed Man Is King!

sfi1

I tried it last night with a silver anti-static bag that you get with some Harddrives. Although not conclusive It did seem to make a small difference to the initial fix. At one stage I was picking up an extra satellite with it compared to without but couldn't repeat this consistently. I see that maplin's do aluminium tape for RFI at 1.79 which might be worth a go.

If a large number of users experience better fix times and it can be shown to work for the majority of users I like onbashi's idea of going to navman (maybe via dave) with the results. Needs a lot more users to try it though. Ideally what they could do is create a new label for registered receivers made out of this stuff which would make it a look more professional and not a home made mod.

onbashi

oh, dave or darren please could you possibly move these messages to the right place because I dont think they belong here, it's slightly off the 3450 topic sorry

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onbashi

I'm glad it has worked for you also, I've been testing it now since the 1st of august and have had some great results, my average cold fix time is 44 seconds, fastest being 36 seconds and slowest being 52 second, a warm test of approximately 20 seconds never higher than 28 seconds, and a hot fix of well lets just say by the time i agree with the terms and conditions of the software it has a fix possibly around 8 seconds.

re-acquisition is a bit difficult to measure, i disable the com port, re-enable it and it re-fixes in about 2 or 3 seconds

i'm glad it has worked for you also and to save you the trouble i have tried various materials and i'm in contact with someone as we speak to try and develop a special patch that may be stuck on the inside of the sleeve, this will also be fine felt covered to stop the little scratches on the back of the ipaq that are a result of using the navman sleeve or any type of sleeve.

All I need is for other people to try it and let me know if they have the same results,

thanks in advance...

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kartracer

Quote: Originally posted by onbashi on 01 August 2003I got some anti static packaging from an old hard drive that I purchased a while back, folded it twice and inserted it between my ipaq and the sleeve.

Thanks for a fabulous idea! I had previously tried to work out something using metal foil, but that was too delicate. An anti-static bag folded once (4 layers) is now stuck inside my 3400. Cold fix times about 30 seconds!
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Kam

pann

onbashi, I got identical results as you by inserting anti static packaging from a hard drive and folded it twice. I must say that I’m very pleased with this. I also tested with aluminium foil (the type you use in the household) but with out any good results so I can also confirm that it seem to work best with foil from an antistatic bag.

Thank you for a great tip!

onbashi

My ipaq has been left for 12 hours with the sleeve removed and i've just tested it again....

44 SECONDS for a cold fix!

i've seen my first 8 sat fix in about 4 months!

i think i'm seeing things!
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In The Land Of The Blind The One Eyed Man Is King!

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