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A quick review on GPS receivers, as this has become a very popular item on eBay.
There are many different kinds available, therefore many aspects of the product to look out for.
As you are most likely aware, the general usage of these items are for SatNav systems, which means that this device will need to have some sort of connection with another device, namely a PDA preloaded with mapping software, or a mobile phone, so Bluetooth v2 is a key advantage.
Older models still use Bluetooth v1.1, therefore it's best to look out for a unit that supports Bluetooth v2.
Number of satellites, this varies with every unit, the more the better, as it connects to more "moons" triangulating your location more accurately. However, its reported that there are only 13 satellites visible [I don't mean visible to us, but the units] over London, of the remaining 30 working GPS satellites [another 22 have been launched since the program started in 1978, but are no longer working.] thus potentially rendering many 20+ satellites units useless.
To note: TomTom Navigator is satisfied with just 3 satellites.
But does that mean the more satellites it can handle the better the unit is? not always.
Many on eBay now advertise a massive 32 sat capability, but this isn't always paramount. I for one, am more interested in its acquisition time [how long it takes to pick up a strong signal from a sat] this is shown as cold start on many listings. So look out for a low cold start time.
Another more technical aspect to look out for when purchasing a GPS unit, is the processing chip inside the device.
There are many companies who develop these chips, popular ones are chips that lead with a BT, like the BT-77 which is a 16channel unit, another more popular chip is the SiRF, now in its 3rd generation the SiRF III, a 20chan/sat unit.
To end, as I'm out of time, after testing many units I believe the Holux GPSlim SiRF III unit rates higher then rest.
As its 20 parallel satellites capabilities is sufficient for any mapping tool, its very quick cold start time, its extremely small size, and the package contents isn't bad too.
Good luck, and I hope this little review helps.
There are many different kinds available, therefore many aspects of the product to look out for.
As you are most likely aware, the general usage of these items are for SatNav systems, which means that this device will need to have some sort of connection with another device, namely a PDA preloaded with mapping software, or a mobile phone, so Bluetooth v2 is a key advantage.
Older models still use Bluetooth v1.1, therefore it's best to look out for a unit that supports Bluetooth v2.
Number of satellites, this varies with every unit, the more the better, as it connects to more "moons" triangulating your location more accurately. However, its reported that there are only 13 satellites visible [I don't mean visible to us, but the units] over London, of the remaining 30 working GPS satellites [another 22 have been launched since the program started in 1978, but are no longer working.] thus potentially rendering many 20+ satellites units useless.
To note: TomTom Navigator is satisfied with just 3 satellites.
But does that mean the more satellites it can handle the better the unit is? not always.
Many on eBay now advertise a massive 32 sat capability, but this isn't always paramount. I for one, am more interested in its acquisition time [how long it takes to pick up a strong signal from a sat] this is shown as cold start on many listings. So look out for a low cold start time.
Another more technical aspect to look out for when purchasing a GPS unit, is the processing chip inside the device.
There are many companies who develop these chips, popular ones are chips that lead with a BT, like the BT-77 which is a 16channel unit, another more popular chip is the SiRF, now in its 3rd generation the SiRF III, a 20chan/sat unit.
To end, as I'm out of time, after testing many units I believe the Holux GPSlim SiRF III unit rates higher then rest.
As its 20 parallel satellites capabilities is sufficient for any mapping tool, its very quick cold start time, its extremely small size, and the package contents isn't bad too.
Good luck, and I hope this little review helps.
Guide created: 22/03/06 (updated 20/10/09)
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