- Will my geko float?
- What is WAAS?
- What NMEA version does my
geko unit output?
- Can I use Loran TD
coordinates with my geko?
- Is the altimeter or
barometer temperature compensated?
- What happens to the pressure
plot as my elevation changes?
- What is normalized pressure?
- What is the difference
between ambient and normalized barometer pressure?
- How can I use the barometer
to track weather patterns?
- Which pressure plot should
I use to track the weather?
- What do the electronic
compass and barometric altimeter provide to the user?
- Why does the elevation on
my unit read 65,000 feet?
- Why don't I see a pressure
- Why don't I see an
- Why is my 'glide ratio to
target' blank while I am navigating?
- Why are the 'total ascent'
and 'total descent' different after making a round trip?
- How do I calibrate the
- Will the calibrated
altitude remain accurate if I move to a new location?
- Can my geko take a pressure
reading while the unit is off?
- Why does my geko show a
minimal pressure change when I know that I climbed 1,000 feet?
- Why does my elevation plot
show a sharp change in elevation even though my elevation has not
- Why does the
barometer/normalized pressure change when I calibrate the altimeter with
a known elevation?
- How do I update the
operating software of my geko unit?
- Is my geko waterproof?
- Can I connect an external
antenna to my geko?
- Why is the time and date incorrect on my geko
Will my geko float?
Currently, only the Garmin GPS 7x and GPSMAP 7x models will float in
water. Garmin recommends the use of lanyards to help ensure that
handheld units are not lost overboard in a marine environment.
What is WAAS?
WAAS stands for the "Wide Area Augmentation System".
WAAS is an FAA-funded project designed to improve the overall accuracy
and integrity of GPS signals for flying in instrument meteorological
conditions, primarily during the approach and landing phases of flight.
It is a space-based system that broadcasts integrity information and
correction data as determined by ground reference stations. At this
time, the system is still in the development stage. The goal is to
provide reliable signals with an accuracy of seven meters (21-22 ft),
both horizontally and vertically, 95+% of the time. Current tests show
the actual accuracy to be on the order of 2-3 meters. (see
For those GPS units that are WAAS enabled, a second antenna is not
necessary to receive the signal.
What NMEA version does my geko unit output?
All Garmin GPS manuals will list the NMEA version (some units output
more than one version) for that particular unit. Generally, this
information is found in the back of the manual, just before the index.
I use Loran TD coordinates with my geko?
Garmin has added the Loran TD format to most new GPS units. This will
allow consumers who have used Loran in the past to enter their old Loran
TD numbers into their new Garmin GPS receivers. The GPS does not receive
a Loran signal. It will simply convert the Loran TD that you enter and
convert it to Lat/Lon for display or navigation. You will need to know
the Loran chain number and the two secondary towers used to record the
position you wish to convert to Lat/Lon or navigate to. If you would
like more information on Loran TDs and your Garmin GPS unit, please see
Loran TD Position Handbook.
Once you have set up your GPS for Loran TDs, you will be able to enter
your Loran TD positions. You can then switch the GPS back to Lat/Lon,
and the coordinates will be converted. Since the GPS unit makes the
conversion based on a static model, there may be error introduced. You
can also get error if an incorrect primary/secondary station is used or
the order of if the two secondary stations is incorrect. Because of this
error, we recommended you mark these waypoints upon arrival, this time
using the GPS signals received for the most accurate position.
the altimeter or barometer temperature compensated?
The barometer, which is responsible for altimeter readings, is not
temperature compensated. Temperature changes in the measuring device
will affect the barometer and altimeter readings, but these readings
will remain within the stated accuracy for the device, approximately 10
feet with proper calibration by the user and slightly higher when using
automatic GPS calibration.
What happens to the pressure plot as my elevation changes?
The ambient pressure plot will reflect your change in altitude because
pressure tends to decrease with an increase in elevation. The
normalized/barometric pressure plot will remain level as the unit is
taking into consideration your changing altitude and calculating this
sea-level pressure. It is important to note that this calculation does
not compensate for temperature or humidity.
What is normalized pressure?
"Normalized" is a term used by the geko 301 and eTrex Summit to
represent the unit’s estimate of locally reported sea-level pressure
(reported from a weather station or airport). Because normalized does
not account for the affects of temperature and humidity on pressure, it
is not accurate enough to be used to calibrate the altimeter. The term
normalized in the eTrex Vista & GPSMAP 76S is replaced by "barometer
What is the difference between ambient and normalized barometer
Ambient pressure is a sensor reading from the unit. Normalized barometer
pressure is the unit's best estimate of locally reported sea-level
pressure for your location. This estimated pressure does not compensate
for humidity or temperature.
can I use the barometer to track weather patterns?
The rise and fall of the barometer indicates the movement of weather
patterns across your area. Typically, a falling barometer indicates
clouding conditions that may result in rain. A climbing barometer
indicates the opposite, or clearing weather conditions. For more
information on pressure trends, there are a number of websites to refer
to as well as many books that will give greater explanation of
barometric pressure and its relation to meteorological trends.
Which pressure plot should I use to track the weather?
The GPSMAP 76S will display one of two pressure graphs: ambient or
barometer over time. Plotting the barometer profile over time can be
used for general forecasting. A falling barometer generally means
clouding weather, while a rising barometer usually means clearing
weather. Because a change in ambient pressure will reflect changes in
both weather and altitude, an ambient pressure plot over time is not a
good indicator of changing weather unless you are certain that your
elevation has remained constant over the plotted period of time. The
geko, eTrex Summit, and eTrex Vista will display only one pressure
graph: a 12-hour ambient pressure profile that is a good indicator of
changing weather conditions only in the event that your elevation has
remained constant over the plotted period.
What do the electronic compass and barometric altimeter provide to the
The electronic compass allows the user to view his and her heading while
either standing still or moving too slowly for the GPS to detect. The
barometric altimeter allows the user to track recent changes in ambient
air pressure. This allows the unit to calculate a precise altitude
reading when properly calibrated.
Why does the elevation on my unit read 65,000 feet?
This is likely the result of a pressure cell in the unit that is not
functioning properly. You will need to return the unit to Garmin for
service or repair. Please either call (1-800-800-1020) or e-mail Product
Support for an RMA number and return instructions.
Why don't I see a pressure plot?
The Pressure Plot page shown on the geko 301 and eTrex Summit will
display plotted pressure values up to 12 hours previous to the current
time; the eTrex Vista 24 hours previous; and the GPSMAP 76S up to 48
hours previous. None of these units will display a pressure plot if they
have not been powered on during the specified number of hours. Clearing
the active track log will not clear a current pressure plot.
Why don't I see an elevation profile?
You must have an active track log (not a saved track log or activated
TracBack) to see the elevation profile. If you have cleared your active
tracklog, you will not be able to view your elevation profile.
Why is my 'glide ratio to target' blank while I am navigating?
Glide ratio to target will only appear if you have activated a GoTo and
the waypoint you have chosen has a listed elevation that is
significantly lower that your current GPS elevation.
Why are the 'total ascent' and 'total descent' different after making a
Even when the unit is lying still, it is receiving signals from
satellites and continuously calculating a position. In doing so, the
unit is adding together small fluctuations in GPS altitude which, over
time, produce the larger difference in total ascent and total descent
that you may notice.
How do I calibrate the Barometer?
This is a trick question, so be careful! What you are actually
calibrating when you want to view the correct elevation or normalized
barometric pressure is the altimeter (sometimes called barometric
altimeter). The barometer is simply a sensor that determines the ambient
air pressure, or the pressure around you. Once a pressure reading has
been obtained, you can calibrate the altimeter based on either a known
elevation or the barometric/normalized pressure.
Will the calibrated altitude remain accurate if I move to a new
The calibrated altitude will be accurate only as long as you do not move
into an area where the weather conditions are different. If the weather
conditions are different, you will need to recalibrate the altimeter
based on a new known elevation or correct pressure.
Can my geko take a pressure reading while the unit is off?
When the unit itself is powered off it will not collect pressure
readings. However, you may turn the GPS acquisition "Off" in the Setup
Menu and conserve battery power while continuing to collect pressure
readings. In this case, the unit itself is not off, only GPS
Why does my geko show a minimal pressure change when I know that I
climbed 1,000 feet?
Small pressure changes represent relatively large changes in elevation.
1,000 ft = 1"Hg or ~40mb
For instance, when you begin a hike, you may look at your GPS unit and
notice that the ambient pressure reading is 29.60"Hg. Later, after
climbing what you know to be a 1,000-foot gain in elevation, you may
notice that the ambient pressure reading is now 28.60"Hg. Using the
1,000ft = 1"Hg relationship, the difference in pressure (29.60Hg - 28.60
= 1.00Hg) represents the gain/loss in altitude.
Why does my elevation plot show a sharp change in elevation even though
my elevation has not changed?
The sharp change in elevation may be due to changing ambient air
pressure. This behavior signals the need to recalibrate the altimeter
with either a known elevation or the barometric pressure. This also may
be due to the unit performing an auto-recalibration that uses GPS
elevation to set the altimeter. If the ambient air pressure has been
rising over time and the altimeter elevation has climbed, an
auto-recalibration based on GPS altitude may result in a sharp decrease
in this altimeter elevation value.
Why does the barometer/normalized pressure change when I calibrate the
altimeter with a known elevation?
Because the barometer/normalized pressure is calculated based on ambient
pressure and elevation, changing the elevation will change the
barometer/normalized pressure. For example, if you were to calibrate the
altimeter with a known elevation of 2,500 ft, when the ambient pressure
was 27.40" Hg, the barometric/normalized pressure would be around 29.90"
Hg. This is based on the following rule of thumb: 1" Hg = 1,000 ft. If
you were to recalibrate the altimeter while reading the same ambient
pressure, but with a new elevation of 2,000 ft, the barometer/normalized
pressure would now read about 27.90" Hg.
How do I update the operating software of my geko unit?
See Firmware >
my geko waterproof?
See the Specifications page.
Can I connect an external antenna to my geko?
While certain geko models are WAAS capable, none possess the ability to
attach an external antenna. If you are looking for units that do have
the capability to use a remotely mounted antenna, please look at our
other products outside of the geko family. A variety of product options
- Why is the time and date
incorrect on my geko 101/201?
The GPS satellite system communicates the date via a week number that is
limited to 1024 weeks (about 20 years). On April 6th, 2019, the week
numbers broadcast by the satellites will “rollover” to zero. GPS
receivers that don’t account for this rollover in their software will
calculate the wrong date and/or time.
The geko 101 firmware can not be updated in the field, and due to the
age of the geko 201, Garmin have announced they will not publish an
updated firmware to correct this issue.
The Garmin geko 101/201 date and/or time will be wrong after the GPS
Rollover on April 6th, 2019. However, all functions not dependent on
date and/or time (position, velocity, navigation, etc) will continue to
work normally. All Waypoint, Track and Route data will continue to be
accurate other than the date/time.
Tip: Many geko owners have reported
the Garmin EOW software
successfully corrected the date/time issue on their geko 201.