The venerable Garmin GPSMAP 76Csx has been around for a few years now but is still an excellent GPS to use for geocaching. The Csx refers to C for Colour screen, s for Sensor (compass and altimeter) and x for micro-SD card.
Important features for geocaching include:
- Sensitive GPS receiver
- Electronic compass
- Bright colour TFT screen -readable in any light
- Ability to upload maps
- Micro-SD card for storing waypoints and maps
- Ability to store 1000 waypoints
- Rugged and waterproof
The circuitry in the 76Csx is identical to the 60Csx and therefore they are functionally the same.
It uses the SiRFstarIII chipset which are the receiver and processing chips that receive the signals from the GPS satellites, calculate the co-ordinates and run the software in the unit.
It means that the unit is more sensitive under tree canopy and in urban (or natural) canyons. In difficult environments like these the GPS will receive both direct and reflected signals that bounce off hard surfaces and cause multipath reflections. This introduces errors into the process and is why you have trouble locating caches in these sort of conditions.
The SiRFstar III chipset has the processing power to crunch the numbers from all the reflected signals and come up with something meaningful. This processing power also means that the chipset can consider weak signals that were ignored by previous chipsets. The SiRFstar III also has faster acquisition times, making for a faster time to first fix (TTFF), and a quicker reacquisition if the signal is lost.
When we learn how to geocache we are trying to locate a container within small radius. So often we are under trees or in between buildings, and it's in situations like these that the amazing reception of the 76Csx comes in handy. This sensitivity is just as important when placing a cache. In addition the 76Csx has the ability average co-ordinates to improve the accuracy of placement even more. I have placed many caches using this unit and finders report very accurate co-ordinates even in difficult locations.
Garmin claims a battery life of about 30 hours using normal alkaline batteries. I used rechargeable 2700 mAh batteries and although I never actually timed hours of operation I am able to do several geocaching runs over a number of days on the same batteries.
The 76Csx comes with a base map of whichever country you bought it. However you can upload other maps that take priority over the basemap. In fact you can upload a number of maps via the USB port and select which one is displayed.
The unit comes with Mapsource which enables you to upload various maps and waypoints.
Using the GPSMAP 76Csx
The unit has the typical Garmin interface and buttons.
The unit has 6 main pages; Satellite page, Trip computer page, Map page, Compass page, Altimeter page and the main menu. You cycle through the pages by pressing the MENU button to go forward and the QUIT button to go in reverse. Extra pages can be added in page sequence option of the main menu.
The 76Csx is "geocache ready" which means that it has a two waypoint symbols; one for unfound cache and other for found caches. It also has a calendar feature that shows when you found the caches. It also has a search feature for geocaches that is separate from normal waypoint searches.
I use the GSAK Smart Tag feature to create meaningful waypoint codes that indicate type of cache (traditional, multi etc.), container size, terrain, difficulty and text for the hint. This appears on the compass page under Notes. An annoying feature of the Compass page is that it is too easy to hit the Found button and remove the cache from the list of unfound caches. If you do accidentally hit the Found button, you have to find that cache in the list of waypoints and change the symbol back to an unfound cache.
The nice thing about having an electronic compass is that it will point to the cache even when you standing still. When using GPS units that don't have this feature you have to be moving before the needle will point to where you need to go.
However it is important to calibrate the compass. If you don't calibrate the needle will point in the wrong direction when you trying to find a cache. To calibrate, go to the Compass page, hitting menu and selecting Calibrate. When you select Start you turn at a certain speed until the unit tells you it has finished.
As is typical of Garmin units it is rugged and waterproof. In fact it is rated to IPx7 (Ingress Protection rating), which means that you can submerse it in water to a depth of 1m for up to 30 minutes. The backside of the unit has rubber covers for the battery case, antenna and power connectors.
A handy feature if you're canoeing or boating is that it floats. I don't know how they build it so light. The newer Oregons and Colorados are much heavy and would sink like a stone if dropped them overboard.
It certainly is rugged. I was using it to navigate while flying my hang glider. It had a nasty whack when I had a "non-optimal" landing but like a Timex watch, it took a lickin' and kept on tickin'.
The Garmin GPSMAP 76Csx is an excellent unit for geocaching because it has high sensitivity, a colour screen that is readable in any light, an electronic compass and a number of specific geocaching features. In addition it is rugged and waterproof so that it will handle any conditions that in which you may be working.
Because it is now over five years old, you can pick them up for a few hundred dollars. If I had the choice I would recommend one of these over something like an e-Trex if you could pick it up for the similar money. I would also choose a 76Csx over a 60Csx because of ability to float and be used as a marine GPS.
In summary, the Garmin GPSMAP 76Csx is an excellent unit for geocaching. It's an oldie but a goodie.