Etrex Vista HCX - A few observations

[+Tui Chub]

I've had my Vista HCX for about 3 weeks now, here are a few of my observations.

 

Battery Life:

I did a simple battery rundown test. I set the HCX to log a trackpoint every 10 seconds, I had WAAS on and logged to both the internal tracklog and external GPX file on a microSD card. I clicked on the backlighting a half dozen times. The HCX was sitting on a desk in my house and not moved. I was using CTA DB-24 (2400mAH) AA Ni-MH batteries. The result of this non scientific test was a battery life of 18 hours and 14 mins.

 

WAAS Observation:

Along with the battery test, I was curious about WAAS vs Normal mode. I did a second test as above but with WAAS off and for about 14 hours. The results were plotted in Google Earth, the location was in Reno, NV USA,

 

Here's the trackpoints for WAAS off.

http://

http://www.tccycling.com/misc/HCXNormal.jpg

 

With WAAS on.

http://

http://www.tccycling.com/misc/HCXWAAS.jpg

 

And Both together.

http://

http://www.tccycling.com/misc/HCXBoth.jpg

 

I do not know the exact location of the GPS in the house but there was less dispersion with WAAS than in Normal mode. The WAAS XY Variance = 2.79, the Normal XY Variance = 7.00644. The difference in the the two averaged location was about 1.6 meters. Another measure of dispersion is looking at the 95% ellipse area; For WAAS it was 52.4 meters^2 and for Normal it was 130.6 meters^2. So at least to me it looks like WAAS does help.

 

GPS Reciever Sensitivity:

This is subjective with no data to account for it. I used both my HCX and a 60 Cx from work. I had one in each hand as I walked in a moderately heavy, second growth, Eastern Sierra Nevada, Pine/Fir forest. Both GPSRs constantly held from 6 to 9 satellites, I consistently had WAAS corrections thoughout. This is in an area where a Etrex Legend C would only track 1 to 6 satellites, failing to hold a consistant fix and definately no WAAS. I can't say which was actually better, in my opinion they're pretty much equal. One other thing, reception appear to be pretty much equal for both GPSRs when held either horizontal or vertical.

 

Some other stuff:

I was marking fish capture locations with the HCX. I got a "Calender Full" message after 503 waypoints. The Vista HCX has a 1,000 waypoint max but evidently can only have about 500 calendar entries. I haven't tried but I assume I need to unselect the save to calendar in the Geocache Option to off to get more Waypoints.

 

There is definately a problem with the trip computer for walking. The HCX had half the distance as the 60 Cx. I'm sure this won't be a problem for biking and vehicles. The minimum speed for logging seems to be about 2.5 miles/hour. The new Compass Calibration nag screen is a pain but can be worked around until fixed.

 

All in all an excellent GPSR that will no doubt get better with future firmware upgrades.

[+Tui Chub]

I tested my twenty-four CTA DB-24 (2400 mah) NiMH rechargable batteries and they ranged from 1200 to 1700 mah with most of them around 1500 mah. With that in mind, I retested the battery life of my Vista HCX with some brand new Powerex 2700 (2700 mah) batteries. I purchased four and they all test out to be around 2600 mah. In addition, I tested a pair of Energizer Lithiums and a pair of Duracell Ultras. The battery type was changed in the gps to the corresponding battery, Lithium for the Energizers, Alkaline for the Duracells and NiMH for the Powerex.

 

The results are:

Energizer Lithium – 46 hr 9 mins

Powerex 2700 (NiMH) – 32 hr 8 mins

Duracell Ultra (Alkaline) - 29 hr 1 min

 

The NiMHs beat the Alkalines by 3 hours. The Lithiums were way out ahead by another 14 hours.

[gallet]

When I got my hcx I was amazed how it just seemed to keep going, like 4 days. As opposed to my old monochrome vista that never saw out a day.

 

I did a continuous on test with the compass on full time with some 2700 NiMH batteries, and it went for the full 25 hours with a bit of backlighting thrown in.

 

The battery indicator remained on 4 bars up until a few hours before it ran out. When it had 2 bars on it, if I changed the unit to read 'alkaline' then it would power off, but still worked for a couple of hours if it was left on 'NiMH'. I thought that this only affected the display but it must detect voltage and shut off.

 

I have heard that the big voltage (1.7) on lithiums can cause a problem, does anyone have any more info on this?