This is a multi-part message in MIME format. --------------422832BD4909 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Thanks for the helpful comments from several correspondents! Keep them coming. Joe --------------422832BD4909 Content-Type: text/plain; charset=us-ascii; name="GARMIN1.NEW" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="GARMIN1.NEW" Initial Observations on the Garmin 12XL by Joe Mehaffey and Jack Yeazel Revised 2/1/97 I (Joe) recently received a new G-12XL and Jack and I have been comparing it to my Magellan M-4000 and Jack Yeazel's Garmin G- 45.. We wish we had an Eagle Explorer to test with also. See below. First, a review of features and operation. Most of the features are the same as the Garmin 45XL unit according to news group correspondents. As others have mentioned, the G-12XL does lock on to the SV signals quickly. From a "cold" start, after a 2000 mile UPS trip, it locked on in 56 seconds. After a 3 hour off time, the lock up time was 20 seconds. Specifications are "warm start" , 15 seconds, "cold start" 45 seconds, "autolocate" 5 minutes. My Magellan M-4000 took 95 seconds from a "warm" start situation in the same environment. Jack's G-45 is a bit faster. A new feature that I have not seen before is the "Initialize by Coun- try" feature. Apparently, this enhancement was made on the Garmin 45XL version as well. With this feature, you may select your country from a list and it will speed up the Autolocate from an unknown location. The specification for position accuracy is 100 meters with SA, 15 meters exclusive of SA and 5 meters with suitable DGPS correc- tion signals. This is considerably better than the DGPS specs available with most low cost single and dual channel multiplexing systems. This shows that reduced error capabilities are achiev- able with even low cost multichannel receivers as compared with single and dual channel units. An averaging mode is available in the G-12XL to improve accuracy in the presence of SA. I have observed error estimations in the range of 50ft with a few minutes of averaging at a spot. We hope someone will test the G- 12XL in a controlled environment and let us hear how accurate the G-12XL's indicated error measurement readout really is. The G-12XL operates from 4 AA batteries or from external power in the range of 10 to 40 volts DC. In one place in the manual, 10 hours is stated as the battery life, and in another it is stated as 12 hours. We have not tested this parameter. The data/power cable used is the same as the Garmin G-45 units. The external antenna connector a miniature coax connector is located on the rear of the unit just behind the "up arrow" button. I have not been able to locate a mating connector at my local RF connector store. (Anyone know a part number and mfg.?) The unit puts out a variety of NMEA protocols, 0180, 0182, 0183 ver 1.5, and 0183 ver 2.0. Other proprietary sentences are output as well. DGPS signals in the RTCM-104 format are accept- ed. A setup screen permits selection of the I/O combination needed by a particular application. The G-12XL has a number of features and displays that are useful. These include: a) A tape type compass display screen showing direction of travel, track bearing, speed, trip distance, altitude, lon/lat position, and time of day. On the 12XL, you must set in the time offset from UTC manually. This display can be alternated with two pushes of the "enter" button with the compass display below. b) A compass type display screen shows direction of travel and has an arrow pointing to the next waypoint. This screen also provides the name of the next waypoint, the bearing, distance, along track speed, speed, cross track error with reference to the next waypoint. c) A highway page type display screen shows off track distance similar to a CDI display. The CDI scale is adjustable in units of .25, 1.25, and 5.0 sm, nm, or km. This screen includes bearing, distance, track over ground speed, speed over ground, estimated time of arrival, and velocity made good, all with reference to the next waypoint. The name of the next waypoint is also displayed. If you get too far off course, a message is presented telling you the proper course to steer to get back on course. d) A moving map display is provided to plot your course over ground. In addition, bearing, distance, track over ground, and speed over ground are provided on this same display. Any waypoints saved in the machine are displayed on the moving map page as they come within range of the map scale selected. Note. The "map" is a blank page until you put in your waypoints. This screen has pan and zoom and scales from .2 mile to 320 (miles or other units) which works quite intuitively. You can "point" at a waypoint on the map and the distance and bearing to that waypoint from your present position will be displayed. You can also "mark" and store a new waypoint by moving the cursor to the desired position on the map and pressing the MARK key plus ENTER. The map may be north up, or current track up. The map display can contain position range rings, plot straight lines between waypoints, display "nearest" nine waypoints, or put names beside waypoints. The map screen also supports zoom and pan features. e) A distance and sun screen is provided to compute the dis- tance between any two waypoints and to display sunrise and sunset information for your locality. f) A simulator feature provides display of simulated motion and simultaneously outputs simulated tracking data to your computer for test of mapping software, data gathering simulations and such. g) A screen backlighting timer permits setting the backlight to 0, 15, 60, 120, and 240 seconds when the unit is on bat- tery power. The screen will stay on continuously if exter- nal power is connected and the backlighting is turned on. The backlighting is uniform and tinted blue and the display at night is easy to read. The display is clear and appears to be the same resolution as that on the Garmin G-45. Screen contrast is also adjustable on the setup screen. h) You can turn off the warning tone! A screen permits beep on warning messages, keystrokes and warning messages or NONE. i) A message screen page allows you to view system warnings and messages. These include such things as approaching way- point, no DGPS position, poor gps coverage, and battery is low. The total number of such advisory messages is twenty one. j) A satellite status page comes up when you first turn the unit on. It displays a "fuel" or battery gauge showing battery remaining, and a "compass" display of satellite numbers (1>32) in view along with signal strength bars for each satellite potentially in view (up to 12). If the unit is powered from an external source, the "fuel" gauge bar disappears. The signal strength bars are hollow if the GPS has found the SV and is not yet locked and changes to solid black when lock is made to each satellite in turn. Each signal strength bar is marked with the associated satellite number. k) Waypoints may be named with a six character name. l) A track log is provided which can log from 0 to 999 points. If 999 points are selected, the track log actually appears to record 1024 points and 1024 points are also referenced during download on the G-12XL's screen. After the maximum selected number of track log points is recorded, the G-12XL discards the oldest log points as new are added. The user can select "automatic" track log which logs whenever direction or speed changes. Alternatively, one can elect to log a track point at intervals from every second to up to every 99 hours as needed by filling in a hhmmss entry in the track log screen. m) A track back feature provides the ability to steer you backwards along your initial outward course without your having to have entered waypoints manually during your out- ward transit. n) The G-12XL accepts the RTCM-104 version 2.0 DGPS correction format version. The GPS can control the frequency of suit- ably equipped DGPS receivers when it is set to the RTCM/NONE mode (No NMEA data output.). DGPS beacon frequency and signal strength will display on the G-12XL when DGPS activi- ty is present on the RTCM input. o) External I/O signal modes available are: NMEA/NMEA, RTCM/NMEA, GRMN/GRMN, and RTCM/NONE. Alert messages alarm DGPS signal failure when that mode is enabled. p) A waypoint proximity alarm can be programmed to alert the user with an audible "bong" when the selected waypoint is being approached. q) The user may select a Magnetic heading reference or true north as required. Other options are grid reference and User selectable. r) The G12XL has 107 built in map datums plus the capability for users to set in their own datum settings. s) The user may enter his own grid format if desired. Subjective Observations of Performance Jack Yeazel and I have been out testing the 12XL on the road and in the field. It worked without a flaw that either of us could find. We uploaded and downloaded waypoints, tracks and routes using Waypoint+(W95), and G7to..(W3.1). We tried it out on SA4 and Delorme MapExpert, and Vista. No problems found. We compared it with the G-45 (not an XL) and with our earlier ex- periences with the G-45 tested against the M-4000 for lock times and the ability to hold lock under various situations. In a sen- tence, the 12XL outperformed the other two in every test for lock stability, multipath performance, re-lock after an under- pass, and ability to suddenly change direction without loss of lock. We were very impressed. We tried the G-12XL (barefoot [antenna wise]) on the dash with the G-45 with external amplified antenna mounted to the windshield. Still the G-12XL outperformed the G-45 in every test. We were very impressed at the speed that the speed the G-12XL responded to changes in direction as com- pared to the other two units. At about 4mph, the 12XL would complete a change of direction in about 15 feet, the G-45 about 50ft, and the M-4000, about 60ft. The G-45 laid down smooth tracks on our highway maps during all tests. No gaps, jumps, etc., The G-45 had a number of minor jumps perhaps a few hundred feet at most in multipath situations. The M-4000 did the same with a couple of jumps out to perhaps 800ft but returning within perhaps 30 seconds once lock was re-established. Note: We were not able to test the unit under heavy tree cover as it is winter in Atlanta and most leaves are off our trees. Perhaps someone in the tropics or Southern Hemisphere with a Garmin 12XL can give us a report. These are the major features We have observed in a day of playing with the G-12XL. Our initial impressions are that the G-12XL is an improved G-45XL with a much faster acquisition of satellites and a well thought out user interface. There are a few addition- al features that will appeal to many, particularly the improved receiver performance and quicker lock. The more frequently used display items are easy to use, but the more obscure require several screens and menus and half a dozen button pushes to access. All in all, We like the unit much better than the older units we have tested. (No.. We did not have an EE to test, but likely it would track about as well as the G-45XL, but as of now no data cable or software is available for mapping or upload/download with the EE to the best of our knowledge. Unfortunately, it is hard (for us) to dynamically test a GPS without the use of a moving map system attached. We made these tests using two Toshiba 2150C laptop computers both running moving map software. The two gps units were operated simultaneously on the dash in front of the driver (G-12XL) and with amplified external antenna on the lower part of the windshield in front of the passenger (G-45). The laptops were positioned so both displays could be watched simultaneously and then we drove over a course of perhaps 30 miles and made observations of the relative performance of the GPS equipment by observations of the "cookie trails' on the moving map display. Dropouts of the G-45 for instance would show a break or jump off the track of the "cookies" for that unit. Jack and have I performed these tests as a matter of personal interest and for our own knowledge. Unfortunately, we cannot compare the 12XL with equipment we do not have and the cost of procuring a number of GPS units just for testing is beyond our budget. Several correspondents were concerned because we did not include the Eagle Explorer in our evaluation. Jack and I will be happy to oblige if someone will send us an Eagle Explorer and a data cable for a few days of comparison testing. Please contact us before any such shipment. If anyone has any additions, questions, suggestions, error corrections other comments, please feel free to Email Jack or Joe. Joe Mehaffey and Jack Yeazel w2jo@bellsouth.net river5@peachnet.campus.mci.net  --------------422832BD4909--