Mark D Stephens: Adventurer, writer, photographer, ambassador of the sonoran desert
.

Navigation
Home > Jeep > Equipment Review

Equipment Review and Evaluation:
Garmin GPSMap 76S and RAM Mount

GPS and RAM Mount for JEep wrangler TJ Garmin GPS receivers
RAM Mounts American Made GPS solutions

"For centuries, the only way to navigate was to look at the position of the sun and stars and use dead reckoning."
from: The Global Positioning System: The Role of Atomic Clocks
Benefits of GPS use
Old Navigation toolsIt's easy to say that using a GPS is all about "not getting lost" or for finding your way when you are lost. But it's actually much better than that . . . navigation. It's got a nice ring to it doesn't it? Navigation.

Using elements of navigation with a GPS receiver while driving backroads and expedition routes allows you to:

  • Estimate time and distance to significant sights (ruins, mines, ghost towns, etc), crucial turns, fuel/supply stops, etc
  • Survey topographical maps of the immediate area
  • Plan a route
  • Record Lat/Long coordinates in emergencies
  • and much more

About GPS: GPS stands for Global Positioning System, which is not the electronic doo-dad you buy that has the little screen and some buttons. That's the GPS receiver. The Global Positioning System is actually a constellation of 27 Earth-orbiting satellites - 24 of which are active and 3 are on standby in case one of the 24 fails. Each one orbits the globe every 12 hours and in a formation that ensures every point on the planet can have radio contact with at least four satellites. Conceptualized by the U.S. Military in 1973 and fully executed with all 24 active satellites in 1993, GPS became available to the general public as well.

A GPS receiver is what we use to navigate by the constellation of satellites.

The GPS receiver discussed here is my Garmin GPSMap 76S.
The mount is a RAM-B-138-GA6U by RAM (double ball joint on a metal base)

I quickly learned that I needed a place to mount said receiver after using it in the Jeep, which prompted me to buy a plastic Garmin mount. It broke. I was referred to RAM Mounts for the ultimate mounting solutions by Chris Shontz of ixplor.us.

First impression
Garmin GPSMap 76S:

RAM Mount:

IGPSMap 76S on a RAM mount purchased the receiver simply under the pressure that everyone else I knew had one. With no idea how they worked or why I ought to have one, I dropped some $400 on the 76S several years ago. Though I loved the large screen, and the rugged feel, it had all kinds of features I didn't comprehend. It turns out the 76S is designed for nautical industries - so it has some sweet features like barometric altimeter, electronic compass, sun/moon information, and tide tables. It also has a rapid way to create a waypoint with the man overboard button (MOB). At first, I was not very excited about these features, but as I use them I love them.

The RAM Mount gave me nothing but great feelings when I saw it. The metal base has mounting holes for screws (or rivets in my case), and the double ball joint that locks into any position you want with a thumb-actuated screw. Very sweet. And inexpensive.

Installation
Garmin GPSMap 76S:

RAM Mount:

The Garmin receiver installs into the RAM mount cradle with a simple "click."

While the mount is perfectly rugged for off-highway use, it requires a some involvement to get it installed properly. Since breaking the plastic Garmin mount, I thought the effort to install the RAM was just fine - results are worth the effort. I should note that RAM makes a wide variety of mounting solutions and I elected for one that bolted in on purpose - I need a durable method of holding the receiver while driving rough tracks and rocky roads. However, I didn't use bolts but rivets (explained at the bottom).

They do make a point about placing the receiver mount in such a way that it won't interfere with an air bag deployment or your visibility. I have it placed in the center of the dash in the little top tray. See the photos at the bottom.

Performance
Garmin GPSMap 76S:

RAM Mount:

Jeep TJ Wrangler offroading off roading with a GPS and RAM mount There is very little to complain about here.

The GPS receiver took me some time to learn to use, but I love several features: variable data fields on the map screen (speed, altitude, time to next, heading, etc etc), viewing data figures after a trip (highest and lowest elevations reached, total mileage, etc), location of moon and time of sunset/sunrise for a given day, and more. I'd prefer a color screen now. One problem is that it only takes 2 AA batteries, so battery life is very limited. For the most part, I keep it plugged into teh 12-volt socket in the Jeep.

Here's an utterly useless, but seriously cool, feature: The receiver floats and is water proof. I suspect that having this water proof unit is good driving in dusty conditions, though.

Due to the Jeep's windshield being nearly vertical - thereby potentially blocking satellite reception - I've installed an external antenna. I rarely experience blackout periods except in tunnels or severe tree coverage.

The RAM mount allows any user to lock the receiver into any position on the fly. Plus, it remains positioned over any level of bouncing and rugged terrain. You do need to be certain that you've locked the thumb screw tightly, otherwise it will slowly allow the cradle to "drop."

Value
Garmin GPSMap 76S:

RAM Mount:

I paid close to $400 for the receiver in either late 2002 or early 2003 - I can't exaclty remember. As far as GPS receivers are concerned today, I could probably do much better for the same money. But I enjoy using the unit, and (again) I love the variable data fields that are available.

This particular RAM mount is about $30 retail, and easily worth every penny. The plastic mounts available from Garmin, on the other hand, are simply inferior; they deflect, and break too easily to be used off the highway. The RAM product also accepts a nice magnifying lens for the screen (sold separately). It's a great solution.

Evaluation

I refer to this alot, but the time my wife and I broke down near Coalson Ranch, some 25 miles from help, I had my GPS receiver. When I made a satellite phone call for help, I was able to give my precise location with lattitude and longitude coordinates. I'd called my dad, and in turn he called the Greenlee Sheriff's Office to report that we were stranded in the middle of nowhere. Here's a snippet from their phone conversation:

"He gave me the coordinates from his GPS" my dad told the sheriff.

"PERFECT! That makes things much easier. Read me the coordinates, and well go get 'em." Replied the sheriff.

In that instance, the GPS receiver saved my ever-lovin' keester by streamlining the search part of the rescue.

With the excellent benefits that come with using a GPS receiver, this is a smart addition to any Jeep headed into remote places. With that, here is how I put the GPS receiver and mount in the Jeep

RAM Mount in Jeep I started by removing the center section of the dashboard. It's just a matter of lifting the grate (near the windshield) out, and removing two screws.

Center section pulls forward and slightly up.

There was not enough space to have a bolt stem and nut protruding inside the dash with the A/C vents; nor could I bolt from the inside out, as the bolt head is also too tall to allow the center dash section to go back into place snugly.

Therefore, I used rivets. Required measuring the thickness of both the mount base and the tray in the dash to use the correct rivet.

Ram Mount attached to dashboard of JEep TJ Wrangler I also cut the rubber mat that rests in the tray, to contour the circular base.

Here the locking arm is placed on the mount base ball.

GPS Mounted with a RAM mount in a JEep wrangler TJ Attached the GPS receiver into the cradle, and the backside of the cradle has a ball that inserts into the arm. Hence, we have a double ball joint that can swivel and swing the receiver into any position and at any angle.
RAM Mount GPS Jeep TJ wrangler 2002 Thumb-actuated screw locks the arm and joints at once for rock-solid positioning.
GPS unit mounted in Jeep TJ wrangler "Bring me my brown pants!" cried the captain.

Now, the navigator can reach and read the GPS receiver while cruising a Baja track or rocky trail.

GPS screen at night illuminated green The GPSMAP 76S has a lumination feature.

You can see the variable data fields at work, which I have laid out like this:

Speed Avg Mov. Speed Pointer
Trip Odom Heading Elevation
Time of day Dist. to Next Time to Next

When I shot this photo, you can see I was travelling 62.4 MPH (someone else was driving), with 13.33 miles to the next waypoint on our route, and it was 7:32 at night. Heading was 222 (southwest). Elevation 2332 feet. Etc.

External GPS Antenna on a Jeep 200d TJ wrangler The external antenna has a magnet base. I ran the cable through the weather stripping between the windshield and Jeep body; this means I had to lower the windshield to do so. It's a little more involved than I thought, but fun nonetheless.
.
random quote

GPS History
Read Beyond Discovery for an excellent article on GPS history and discussion about atomic clocks. I never knew that they had such an elemental role in satellite nav.

Mark D. Stephens: Adventurer, Writer, Photgrapher and Ambassador of the Sonoran Desert