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Guest Miles678

Comparison of GPSMAP 76 vs Vista

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Guest peter

s the newer units only output 2.5VDC.

GPS signals are much weaker than those for typical radios, TVs, phones, etc. and therefore there is a big advantage in amplifying the signal right at the antenna before it can pick up external interference as the signal goes through the cable to your GPSR. Look up the specs for GPS antennas and you'll see that almost all include amplifiers and need to have power supplied either directly or from the GPSR.

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Guest mcb

quote:
Originally posted by Anton:

 

Have Mehaffey and Yeazel done voltage measurements on GPS antennas? If so, let's see the numbers, or add a link here to a page that has them. I'm not convinced.

 

Anton, 10H/9F


 

As requested here is a good page from Jack and Joe's website that confirms what I said.

 

http://joe.mehaffey.com/gpsantrev1.htm

 

In short it states that the GA-26 GA-27 draw about 5Vdc@30mAmax. This will be slighly diffrent if you are running one of the new 2.5V compatable antenna. It also states that the MightMouse draws about 5Vdc @ 12 mA max, typical 10.5ma. The artical goes on to mention several other amplified antenna.

 

I am sorry I made it sound like I was making an assumtion. I new for a fact that Garmin's and the mighty mouse antenna where amplified. I just wasn't sure how much power they drew. Hope this info helps

 

mcb

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Guest Jebediah

Can anyone tell me about a couple of things about the GPS76:

 

1) What's the real-life average battery life on alkalines?

 

2) Does the power button take some effort to engage, or could the power button get bumped on accidentally if the receiver was in a pack or pocket?

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Guest Artful Dodger

quote:
Originally posted by Jebediah:

Can anyone tell me about a couple of things about the GPS76:

 

1) What's the real-life average battery life on alkalines?

 

2) Does the power button take some effort to engage, or could the power button get bumped on accidentally if the receiver was in a pack or pocket?


 

I get about 14-16 hours out of my GPSMAP 76.

 

The ON button has to be pressed for about a second or two in order for the unit to turn on thereby cancelling out any accidental switch on.

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Guest kc2hsu

I am also trying to decide between getting the Etrex, the Etrex Vista, or none. I would do probably a little amount of Geocashing, would use it on the bike, in 2 years, use it in the car, climb some mountains, but would surely use it for APRS. Also, when I start driving, GPS units may become standard in cars, or dramatically cheaper. I need some opinions here, and would love to hear them. Also, Miles, this fourm helped alot. Replies can be sent to kc2hsu@arrl.net. Thanx.

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Guest Anton

Power button on Map76...

 

Yes, it can be turned on by accident if steady pressure is applied inside a backpack or clothing pocket. I've done this twice, and ended up low on battery life. I'm hoping the AccuCase company comes out with a semi-hard case for the Map76 sometime soon. They already have models that fit the eTrex and 12-series Garmins.

 

Amplified GPS antennas...

 

Thanks for all the detailed information that's been provided here by several people. Now we all know what's going on the the power consumption and how these antennas can battery life. Of course, using a cigarette lighter power cable in a car makes it a moot point. Those who use an external antenna out on the trail should carry extra batteries!

 

Anton, 10H/10F

 

------------------

Anton Ninno - N2RUD

Syracuse, NY 13210

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Guest mfratto

kc2hsu, forgo the Vista unless you have money to burn. It's a nice unit, but it suffers from not being able to maintain satellite lock under heavy coverage and the altimeter doesn't seem to be wholly accurate. The 24 meg of memory sounds like alot, and it is, but chances are you will never use more than a quarter of it.

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Guest Anton

External antenna & GPS Map76...

 

While driving in Syracuse today, I made comparisons of signal reception with and without the external antenna connected. As I suspected might be the case, the external antenna made only a slight improvement.

 

Previously, I used the same antenna with a Garmin GPS 12MAP, and the antenna made a very significant improvement in signal reception. In both cases, the external antenna was not outside the vehicle, but only next to the windshield to get a better view of the sky, somewhat outside the shielding presented by the roof.

 

Why the difference? Well, the GPS 12MAP has an internal patch antenna, while the Map76 has an internal helical quadrifilar antenna. It seems the later is much more sensitive.

 

BTW, let's refer to GPS units as sensitive rather than powerful. They are receivers, not transmitters. Therefore they are sensitive, not powerful. Please excuse my pickiness about vocabulary, but we ham radio operators need to make this point now and then. :-)

 

Anyone else here care to offer observations about using an external antenna with a Map76?

 

Anton, 10H/10F

 

------------------

Anton Ninno - N2RUD

Syracuse, NY 13210

 

[This message has been edited by Anton (edited 11 July 2001).]

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Guest gstrong1

ix without the antenna.I regularly get a great fix on 6 to 8 birds & #35(waas) is pretty much always lit up.Even under light tree cover, I seem to have very little difficulty pulling in the waas bird.The external didn't make as much of a difference as I thought it would, but it is nice under heavy tree cover.After trying to go on cache adventures with the bloody Vista, I almost feel like I'm cheating with the MAP76.I finally found a unit I can depend on almost as much as I can my III Plus.But the MAP76 features put it over the top.And all the cables for my III Plus,(12 volt,ac adap. & pc transfer) are the same cables the MAP76 requires. icon_biggrin.gif.

 

------------------

Gary "Gimpy" Strong

Rochester,NY

 

[This message has been edited by gstrong1 (edited 17 July 2001).]

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Guest gstrong1

ix without the antenna.I regularly get a great fix on 6 to 8 birds & #35(waas) is pretty much always lit up.Even under light tree cover, I seem to have very little difficulty pulling in the waas bird.The external didn't make as much of a difference as I thought it would, but it is nice under heavy tree cover.After trying to go on cache adventures with the bloody Vista, I almost feel like I'm cheating with the MAP76.I finally found a unit I can depend on almost as much as I can my III Plus.But the MAP76 features put it over the top.And all the cables for my III Plus,(12 volt,ac adap. & pc transfer) are the same cables the MAP76 requires. icon_biggrin.gif.

 

------------------

Gary "Gimpy" Strong

Rochester,NY

 

[This message has been edited by gstrong1 (edited 17 July 2001).]

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Guest Peter Scholtz

I'm convinced the GPSMAP 76 is the way to go. But would you recommend it for use outside the US as some features seem to be US specific such as the tide data?

 

------------------

Peter Scholtz

www.biometrics.co.za

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Guest Artful Dodger

quote:
Originally posted by Peter Scholtz:

I'm convinced the GPSMAP 76 is the way to go. But would you recommend it for use outside the US as some features seem to be US specific such as the tide data?

 


 

Thats about the only US specific feature of the device. It obtains this info from many marine points around the USA that can be selected. These tide info units are not freely available around the world yet. Someone posted this concern on the GPS newsgroup and many people responded by stating that they just use a PC software program for tide information.

 

This unit rocks, Peter. I have one and it has everything I want in a GPS.

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Guest Havasu Desert Rat

I have an external antenna that a HAM friend of mine gave me. Haven't been able to use it yet as I have a Garmin Model 12.

 

The antenna is a Micro Pulse and has a 26Db on the label. Unless I'm mistaken, that's the gain of the antenna. I haven't seen any mention of Db for any of the other external antennas, or the internals for that matter. Is this information available, and if so, how do they compare?

 

------------------

Larry Sallee

aka The Havasu Desert Rat

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