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+12 Channel Gpsr Receivers

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The new Explorists have 14 channel receivers, and I believe the <cough> Cobras do as well.. Perhaps other GPSr's also go over 12 channels?

 

I was just wondering if this addition of channels over the generally standard "12" is an actual feature worth having, or is it just marketing fluff?

 

In my caching area (Ontario Canada) whenever checking the satellite status screen I notice getting a full 12 satellites is quite rare. More commonly I will get locks on from 8 to 10 birds. Sometimes (especially in the car) I may get only 5 or less..

 

So,, what's the deal with creating receivers that accept more than 12 satellites? Do you think this has any advantage at all in accuracy? On the days I get lucky to have 12 satellite locks, presumably there may be a couple more birds overhead that I may get as well if my receiver had more capacity. But would it really matter?

 

Oh and this question has nothing to do with the beaten-to-death "Patch vs Quad" antenna issue so, don't go there :o

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My guess is that it's marketing, Unless you are in the middle of the ocean with clear view of the horizon and in a spot were you can two was birds, it's not going to happen.

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The new sirf III chips even got 20 channels!

In a normal 12 channels receiver, you will not able to get all 12 GPS birds while 1 or 2 channels have been used by WAAS.

So 14 channels may helps

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12 is enough. As you stated, you seldom even get a lock on 12 sats at any given time. But lets say that you did get a lock on 12 birds - what would be the point of getting a 13th, 14th or even 18th signal? Would it give you submeter accuracy? Nope! The lowest EPE I've ever seen on my 60C was 8 feet, and I've had that reading with as few as 6 sats and as many as 11. Come to think of it, I can't say that I've EVER seen 12 on mine.

 

I know they continue to launch more satellites into orbit, and over time we may see more and more signals more frequently. I think it's gonna be a long time before we continually see 12 signals at a time. By the time we see 12 signals on a regular basis and can make use of more channels, my beloved 60C will be way obsolete by other standards. But again, what'd be the point? It wouldn't be any more accurate than it is with 8 signals.

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The new Explorists have 14 channel receivers, and I believe the <cough> Cobras do as well.. Perhaps other GPSr's also go over 12 channels?

 

Do not forget about new iFinder GO/GO2 with 16-channel receiver :o

 

http://www.lowrance.com/Outdoor/Products/iFINDERGO.asp

 

http://www.lowrance.com/Outdoor/Products/iFINDERGO2.asp

 

I don't see real advantage at present time. Thing could change if more "birds" will fly.

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My guess is that it's marketing, Unless you are in the middle of the ocean with clear view of the horizon and in a spot were you can two was birds, it's not going to happen.

I think you meant to say "WAAS birds" and I would agree with you. If it originally made sense to have 12 channel receivers before WAAS it makes equal sense to have 14 channels to cover situations where you might get two WAAS sats.

 

Note that I sometimes get two WAAS signals at 50°North inland in western Canada.

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Its mostly just marketing. First, you rarely get more then 10 or more satellites(at least I never have). Secondly, when a gps is calculating its position, it only uses the 4 best signals from the satellites. Even if you were recieving signals from 14 or 16 satellites, the gps would only be using 4 of them for positional calculations, so it wouldn't increase accuracy or anything.

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If you have a lock on 12, having a lock on 14 won't help much. If you're in less than perfect conditions (i.e. you're not on a boat with a perfectly clear view of every horizon) and there are moving obstacles that will come and go, having more "ears" listening to more channels simultaneously has the potential to help the unit pick the combination with the best signal strength and the best geometry. This is the more interesting case anyway. It probably won't get 14, but it stands a chance of being to get "more" than a 12 channel just because it has more options to choose from.

 

Of course, it's a curve with a sharp knee in it; having more channels than there are visible from your location buys you nothing.

 

http://forums.Groundspeak.com/GC/index.php...0entry1235722

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