GPS Newbee

[rosedog]

just brought myself a garmin gpsmap60, found it pretty good so far, but being new to all this im still a little slow on the uptake. i have loaded all the software, and downloaded some pretty good programs that will let me over lay my tracks and waypoints on top of google earth. i am just looking for a topo map that i can upload on to my garmin, i know they exist in the states, but having trouble finding one here. also is there any topo's i can download off the net that i can over lay my tracks on?

next question, when i purchased it the guys at the shop uploaded the latest upgrades to my gps, they also told me of an upgrade? that i can do to get better signal, like when i am in thick scrub etc. does any one know of this? my mate has the gpsmap60csx, which is the ducks nuts, and he can walk inside his house after he has swicthed it on and it doesn't seem to loose signal as fast, also when sitting on my veranda mine will drop out signal after a minute where his will only slightly lose signal but still hold his location on the screen.

is there a way to strengthen my signal? an external antenna is relly out of the question as i also use it on my dirtbike. really im just looking to get rid of the gaps left in my breadcrum trail after ive driven somewhere.

[Risto]

You could look into re-radiating antennas... I don't think the GPS Map 60 has an external antenna input, so a re-radiating one is the only way to go. It basically consists of an external antenna/receiver that goes on the roof and 're-radiates' the GPS signals into the cab where the GPS unit is.

I have a VistaC and while it does sometimes lose its connection, on the whole it's pretty sensitive.

[maca82]

The GPS Map 60 DOES has an external antenna plug...
Get yourself one of those if you want better signal in the scrub...

If you want to use it on your dirt bike it will have just as good a signal (on your handle bars) as it would sitting on your dash with and external antenna... There is NO WAY to strengthen your singal... how would that work?

My advice would be to LEARN about GPS for yourself www.trimble.com and take the GPS tutorial. You'll learn a lot and it's free and it takes 20mins!!! Start from the top (Why GPS?) and work your way down.

People shouldn't go out buying GPS as a toy - it's not a toy, it's a tool! If everyone actually figured it out for themselves BEFORE buying we'd save ourselves a lot of hassle.
Don't buy one just because your mate has one or just because its cool!


~MACCA~

[Risto]

Apologies - I stand corrected. The GPS Map 60 DOES have an antenna input, so this is the way to go.

As for strenghtening/amplifying a GPS signal... Of course that can be done and is exactly what an external (active) GPS aerial does. The link below to one particular unit, for example, offers 28dB amplification. That's the whole point of an active (one that consumes power as opposed to 'just sitting there') aerial... For example, you can buy a small passive aerial for indoor use for a TV or you can buy an active one (which consumes power from mains) and amplifies the signal for better reception. This is more or less the same.

http://www.gps-home.com/gps-products/MCX.aspx

[maca82]

It is important to say, that having an external areial/antenna DOES NOT make your GPS any more accurate or punch out a stronger singal.
They simply allow better reception for your GPS that is being used in a restrictive environment.

It will NOT strengthen your signal... again... will NOT. As it says in the first line of the link you posted "A GPS receiver is only as good as the GPS signals it receives". It will only allow the GPS to receive a better signal because it's in an environment condusive to better GPS singals. ie on the roof of yor car or bull bar etc.

Re-radiating antennas are a slightly diferent story, as they themselves receive the GPS signal and pump it through. Therefore the re-radiating antenna has it's own receiver, so the signal it sends is reliant on that receiver and it's strength...

All rosedog is after is an external antenna that he can pick up from GME or Anaconda or Johnny Appleseed for less than $100...

[Risto]

The specs are below and it clearly states the power gain is 28 dB. It takes a little current from the GPS, which is what amplifies the signal.

---

Specifications:
Radome: Black Polycarbonate Radome with die-cast base
Dimensions: 2.3 in. (L) x 1.9 in. (W) x 0.6 in. (H)
Mounting (included): Two permanent; two M3 screws for holes on base
Other Mounting Options: Suction cup mount or metal flanges for surface mounting
Power Gain: 28 dB
Operating Voltage: 2.5V~12V DC Power
Power Consumption: 12mA +/- 1mA
Operating Temperature: -40 to +185 degrees F
Noise: 2.0 max.
Impedance: 50 ohm
Frequency: 1575.42 MHz
Cable: RG174/U (in 3, 9, or 16 ft lengths)
100% waterproof

---

It also states:

Amplified (active) GPS antenna for exceptional GPS signal reception. Not passive like Garmin stock antennas.

---

In other words, it's an aerial AND an amplifier built into one.

Tree coverage is a good example, where the signal is weak, but still present. It must be amplified in order to be detected by the GPS unit.

Most GPS's will show you the signal strength from each satellite. Once signal goes below a certain level the lock is lost. If there's an amplifier between the aerial and the GPS (such as in the model at the link above) then the signal is boosted and the lock retained.

[maca82]

Even still... it won't make the GPS receiver strength any stronger. So when it's unplugged from the external antenna (such as when it's being used on the handlebars of a motorbike) it will only be as good as the receiver that's built in...

[Risto]

GPS units don't send out anything - they're receivers!

Each US military satellite is solar powered and has a mere 50W transmitter and considering how far they are (>100km from the earth's surface - much further depending on how close to the horizon they are) sensitivity is very important. As we've all witnessed at some stage... :-)

But either way, 'active' aerials DO amplify these signals. Period.

Can we talk about something else now...? :-)

Cheers, Risto

[midnightsky6789]

word of advice to all ..i am a firefighter and from experience have found thick smoke will stop you receiving a signal so be careful

[Risto]

Dig the quiet edit there maca82... :-)

You might also wanna change 'strenght' to 'sensitivity'...

[maca82]

Dig the quiet edit there maca82... :-)

You might also wanna change 'strenght' to 'sensitivity'...

You like that one??? :-)

[rosedog]

thanks for the replies guys, i really wanted to stay away from an external arial/antenna, but it seems that is the only choice... will let you guys know how i fair...