From mujibur.inmind.com!uunet!in1.uu.net!eskimo!klah Mon Aug 21 14:05:09 1995 Newsgroups: sci.geo.satellite-nav Path: mujibur.inmind.com!uunet!in1.uu.net!eskimo!klah From: klah@eskimo.com (Lane Alan Holdcroft) Subject: Garmin GPS 45 and GPS 40 Frequently Asked Questions (FAQ) X-Nntp-Posting-Host: eskimo.com Message-ID: Keywords: FAQ Garmin 40 45 90 speed limit Sender: news@eskimo.com (News User Id) Organization: Eskimo North (206) For-Ever Date: Mon, 21 Aug 1995 07:36:57 GMT Lines: 1565 Here is the updated Garmin 45/40 FAQ. There is now more information on the GPS 90 and the speed limit in particular and somewhat more info in general. The accuracy should be better also. Garmin GPS 45 and GPS 40 Frequently Asked Questions =================================================== V 1.02 (Aug 20, 1995) The Usenet GPS newsgroup "sci.geo.satellite-nav" has a high proportion of questions dealing with the very popular Garmin GPS 45 and GPS 40. I hope this will answer most of them. Some of this information applies to other Garmin models as well (especially the GPS 90), but this FAQ concentrates on these 2 specific models. This FAQ is based on my experiences with my GPS 45 and others postings to the GPS newsgroup since the GPS 45 was first released about March 1994 (the GPS 40 was released almost 6 months later). I am an electrical engineer and therefore have a particular interest in the electrical aspects of these units. For more general information not specific to the Garmin units, read the new GPS FAQ by Peter Bennett. It is available on his excellent ftp site as listed under "GPS 45/40 ftp/www sites?" in this FAQ. I plan to post this document there also when I feel it is solid enough (probably within a few weeks). Thanks to the many people who contributed to this document! I tried to give credit to the original author at the end of the contribution when reasonable. I didn't give an attribution if it was only a few sentences. If an answer does not have an attribution, then I answered it based on my recollection of previous postings or personal experience. A fair amount of the information posted about the Garmin units in the newsgroup is wrong. I have spent a lot of time trying to make sure this document is error free, but some have been found in the past. You can help improve this document by sending E-mail to me about errors or suggestions for improvement. It would be useful if you could give your sources of information and include your firmware version (displayed on power up). There is often conflicting information and your references are valuable for resolving those discrepancies. I am receiving lots of feedback but it takes time to process and verify all of the information. Because of the large volume of E-mail I am receiving, I can not always acknowledge all mail. I also can not answer any individual questions. I do however read all feedback carefully and will take note of it. Because of the large number of questions that are still being posted to the newsgroup that have been answered in this FAQ, I will start posting this once per week. This document is not in any way endorsed by Garmin International. I am not affiliated with Garmin or any of their retailers. Please send CONSTRUCTIVE suggestions to Lane Alan Holdcroft (klah@eskimo.com) ---------------------------------------------------------------------- TABLE OF CONTENTS: ================= GENERAL FEATURES: -What are the key features of the Garmin GPS 45/40? -What are the disadvantages of the GPS 45/40? -What are the differences between the GPS 45 and GPS 40? -Specifications? -Garmin GPS 45 & 40 reports/description FIRMWARE (GPS 45/40 INTERNAL SOFTWARE) QUESTIONS: -Speed limit? -GPS 90 info? -GPS 45/40 firmware versions? -Are there any undocumented modes? BATTERY/POWER QUESTIONS: -How is power selected between the internal batteries and the external supply? -What voltages do the fuel gauge correspond to? -How does BatterySave mode work? -Battery Options? -How long is the memory conserved without batteries? -Does the serial I/O draw much power when it is enabled? SERIAL/POWER INTERFACE: -External Serial/Power Connector alternatives? -How do I interface the GPS 45/40 to an IBM-PC compatible computer? -How do I interface the GPS 45/40 to a Macintosh? -Internal electrical hardware? -What computer software is available to communicate with the Garmin GPS? -GPS 45/40 ftp/www sites? ANTENNA QUESTIONS: -How is the GPS 40 antenna internally constructed? -How is the GPS 45 antenna internally constructed? -How well does the internal antenna work inside a car? -What are the remote antenna options? -Can I make my own external antenna? MISCELLANEOUS: -GPS Mounting options? -Waterproofness? -Cases? -Garmin Accessories -Can I use my GPS in a plane? -Performance in trees? -Other portable Garmin GPS models? -Where can I purchase a unit? ---------------------------------------------------------------------- QUESTIONS & ANSWERS: =================== GENERAL FEATURES: ----------------- -What are the key features of the Garmin GPS 45/40? Relatively inexpensive (list $500 US, discounted $300 US) The most compact units available and can fit in a tall pocket Originally intended for marine use, but also works for hikers, bikers, and autos Long (10 hour) battery life w/ 4 AA alkaline batteries Over 100 mapping datums used around the world Easy to use due to their simple menu system Water resistant 64 x 100 pixel graphical display Very feature rich -What are the disadvantages of the GPS 45/40? 1) There is an undocumented (firmware) speed limit of 90 knots (see Speed Limit question elsewhere in the FAQ for more details) 2) Because of the GPS's compact size, there is not sufficient space for number buttons. It has a 4 position rocking button to enter numbers and names. This works out fine but is not fast as using a keypad. (The GPS 75 is somewhat larger but does have a keypad). 3) The display is small because it is limited by the size of the entire unit. Hey, this is a compact GPS! If you have good corrected vision, it should not be a problem at arms length. 4) Some options are more expensive than some competitors. For example, a replacement 45 antenna is $100 and external power and/or data cables are between about $22 and $50. -What are the differences between the GPS 45 and GPS 40? 1) The GPS 40 has a compact antenna built into the main case whereas the 45's swivel antenna (about 3/4" x 3/4" x 3") hangs off the side and can be broken if it were snagged or handled roughly ($100 replacement cost!). A GPS 40 looks like a GPS 45 without the swivel antenna. The GPS 45 uses a standard BNC connector and the GPS 40 has an external connector type called "MCX". The GPS 45 can be held at different viewing angles as long as the antenna is vertical whereas the GPS 40 must be held at a more specific angle for optimum reception. There is some debate about the exact differences in antenna sensitivity, but it appears that the GPS 45 is slightly more sensitive for satellites that are directly overhead. 2) The GPS 45 takes a much wider range of input voltages (5 - 40 Volts). This is because the 45 has an internal switching power supply. The GPS 40 does not and is only rated for 5 to 8 Volts for external power. Connecting the GPS 40 directly to a higher voltage supply would be very risky. Because of this, the mobile power cigarette adapter is $20 more expensive for the GPS 40 (because it must include a regulator). Also, the GPS 40 has an additional center pin in the center of the power/data connector to prevent the use of the GPS 45 cord which would probably damage the GPS 40 if too high a voltage was applied. 3) The GPS 40 includes a video on its operation. -Specifications? Here are the specs out of the manual: Physical Case: Waterproof, dry nitrogen-filled Size: 6.15"H x 2"W x 1.23"D (15.6 x 5.1 x 1.23 cm) Weight: 10 ounces w/batteries Temp Range 5 to 158 degrees F Performance Receiver: Differential-ready MultiTrac8 Acquisition Time: Approx 20 seconds (warm) Approx 2 minutes (cold) Approx 7.5 minutes (autolocate) Update rate: 1/sec, continuous Position Accuracy 5-10 meters (16-33 ft) with DGPS correction 15 meters (49 ft) RMS* *subject to accuracy degradation to 100m under the DOD imposed Selective Availability Program (note: I average 150') Velocity Accuracy 0.1 knot RMS steady state [several knots error w/ SA -Editor] Dynamics: Performs to specs to 3g's Power Input: 4 AA batteries or 5-40 vDC Usage: .75 watts Battery life: 10 hours (normal mode) w/alk. batt. Up to 20 hours in battery saver mode Kai Schumann Schumann_Kai@Lilly.com ---------------------------------------------------------------------- -Garmin GPS 45 & 40 report/description: Here are 2 good reviews that were posted last year. One is from a 45 owner, the other is from a 40 owner. Keep in mind that other than the antenna and input voltage range, they are IDENTICAL and most comments apply to both. I included them pretty much in full because they do a very good job of covering the features of these units and they both include lots of useful information which would be beneficial to someone who is contemplating buying a Garmin unit. [ -Editor] From: gscott@netcom.com (Gavin Scott) Date: Wed, 27 Apr 1994 04:46:39 GMT Today I received a new Garmin GPS 45 Here are my initial impressions, along with a list of features and specifications for the unit. I will follow up with more comments in a week or so after I have had a real chance to play with it for a while. I have no connection with Garmin or West Marine. I purchased the GPS 45 myself, for my own use. I have owned handheld GPS receivers going back to the original Magellan Nav-1000 (which has now been upgraded repeatedly and is a NAV5000 now). I have some experience with other GPS units including a Garmin GPS100 owned by a friend. The brand new (shipping for only a week or so) Garmin GPS 45 looks to be the hottest handheld around. It is a small (literally pocket sized) 10oz package, and yet sports a large graphic LCD display. For a picture, look in the current West Marine catalog (you can get one from them at 1-800-538-0775) or most other marine equipment dealer catalogs, or call Garmin at 1-800-800-1020 and ask them to fax you a data sheet. ------- GARMIN GPS 45 --------- PHYSICAL DESCRIPTION: This sucker is small! It easily disappears into the front pockets of my Levis Dockers. The spec sheet lists the dimensions as 6.15 inches high, 2 inches wide, and 1.23 inches deep. Weight is an amazing 10 ounces (spec sheet, 4 AA batteries included), (West Marine lists the weight as 9 ounces (pre release info), and my cheap postal scale weighs it in at 11 ounces (with batteries and case). At the top on the right side is a recessed BNC connector where the tiny built in flip-up antenna is attached. The antenna is of the same sort as the Magellan and Garmin units have used for some time, except for the size! The GPS 45 antenna measures 3 inches long by 0.775 inches square. The dimensions of the main unit given above do not include antenna, which makes the top of the unit about 3 inches wide overall. The most striking feature of the GPS 45 (after size) is the large LCD display which takes up the bottom half of the front of the unit. The display has a 'portrait' orientation, being much taller than it is wide. Above the display is a four way rocker switch surrounded by six other buttons. This layout allows the unit to be easily held in either hand with the thumb operating the buttons. The joystick like flat rubber rocker switch is used for all data entry. Alpha-numeric data is entered by cycling through the possible letters/numbers. To the left of the rocker 'cursor' button are (top to bottom) GOTO, Power/Backlight, and QUIT buttons. to the right are PAGE, MARK and ENTER. The top 1/4 of the front is blank except for a logo (picture of the earth with no text). The front part of the unit is white, and the back is black. Batteries (4 AA) are inserted into the bottom, beneath a seal opened with a quarter turn fold out doohickey. The batteries disappear into two tubes. I don't know where they have room for the electronics with all that space taken up inside by the batteries! A 4 pin (round DIN like) connector is on the back. The pins are described in the manual as Ground, Power in (5-40 VDC!), and DATA IN and DATA OUT. A rubber plug protects the connector when it is not in use. The whole unit is waterproof, and is actually filled with dry nitrogen and the waterproofness is covered by the one year warranty. ACCESSORIES INCLUDED: 4 AA [alkaline] batteries (installed). A very nice soft case with a clear plastic front which allows complete operation of the receiver with the case on. [The case type now used does not allow operation or have a window -Editor] A reference manual (61 pages, dated February 1994). A quick reference card (which is too big to fit in the case, but printed on plastic waterproof paper). Warranty registration card. An offer to sell you a training video for $29.95 A wrist strap. The whole mess comes in a white cardboard box with pale Garmin logos on it that is about 11"x7"x3". SPECIFICATIONS: Temp range 5-158 degrees F (-15-70C). Acquisition times: 20 seconds (warm), 2 minutes (cold), 7.5 minutes (sky search). Update rate 1/second. Position accuracy 5-10M (with DGPS), 15M RMS (without S/A), [100 Meter accuracy with 95% confidence (with S/A on, as is the case now) -Editor] Dynamics: 3g's. Power usage .75 watts. Battery life 10 Hours normal, 20 hours battery saver mode. NMEA INTERFACE INFORMATION: NMEA 0180, 0182. 0183 version 1.5 (Approved sentences BWC, GLL, RMB, RMC, XTE, VTG, WPL; Proprietary sentences PGRMM (map datum), PGRMZ (altitude), PSLIB (DGPS beacon remote control)). 0183 version 2.0 (Approved sentences GCA, GLL, GSA, GSV, RMB, RMC, RTE, WPL; Proprietary sentences PGRME (estimated error), PGRMM (map datum), PGRMZ (altitude), PSLIB (DGPS beacon remote control). Plus Garmin's proprietary bi-directional format that allows upload/download of waypoints and other information with appropriate software. DGPS corrections are accepted from any RTCM-104 v2.0 format compatible beacon receiver, but use of Garmin's GBR 21 (under $500 from West Marine) will allow tuning and control from the GPS 45 itself (using the proprietary NMEA data strings above). OPERATIONAL DESCRIPTION, FEATURES, PRELIMINARY EXPERIENCES: To turn it on, you press the power button down firmly. You are greeted with an animated spinning globe and in large letters "Welcome to the Garmin GPS 45" and it gives the firmware revision as "2.02". First displayed is the satellite status screen. This nifty display shows the position in the sky for each satellite, a bar graph of the signal strength of up to 8 stats at a time, a large battery power gauge bar, a backlight indicator (a very useful feature in daylight when you can't tell if the blue EL backlight is on or not), and a status message ("Acquiring" etc). Pressing the PAGE key cycles through the main displays which are as follows: POSITION PAGE: Shows a graphical compass display (like looking at a compass from eye level). Ground track and speed, Position in LAT/LON down to .001 minutes resolution, Altitude (including an accuracy +- value!), and the current time (Local time not GPS time) with 1 second resolution. MAP SCREEN This is way cool. You get a moving map display that will let you zoom from a 0.2 mile range up to 320 miles. You can also pan around, point to waypoints, create new waypoints by pointing etc. There is no provision for a map database, but the nine nearest waypoints can be displayed with their names, along with range circles, course, ground track, and other information, all configurable. You can have TRACK UP or NORTH UP as you like. CROSS TRACK (CDI) SCREEN: Shows bearing and distance to next waypoint, graphical XTE and distance to go, current time and ETE, Track and Speed, etc. MENU SCREEN: From here you get to enter waypoints and routes and do all the setup stuff. There are about 16 screens of config data and stuff accessible. OTHER MISCELLANEOUS STUFF: Let's see, it is getting late so let me try and highlight the other unusual features. Of course all the stuff for creating routes and waypoints is there. You get 250 Alphanumeric waypoints (which you can add an annotation line of info to!), 20 reversible routes, Man Overboard mode (Press GOTO twice). I have only operated it outside enough to get an initial fix (sky search) and try out some basic stuff and the moving map. If you lose memory (almanac) data or move >300 miles you are forced to do a 7.5-15 minute sky search [unless you enter the new coordinates -Editor]. Once this is done, acquisitions are fast, multiple satellite tracking is quick, and overall the thing seems to work wonderfully. All the usual config options are there (Statute, Nautical, or Metric units, True, Auto magnetic, or Manual magnetic headings). There are 102 different map datums in the system (including some really off the wall stuff), but no option to enter your own (but yours is probably already in there). Positions can be displayed in DDDMM.MMM or DDMMSS.S format or UTM coordinates, or British, Irish, or Swiss GRID formats. CDI scale can be +-.25, 1.25 or 5 Miles or kilometers. You can choose to display CMG/VMG rather than track/speed. There is a simulator mode [which simulates strong satellite reception so you can practice operation of the unit. -Editor]. The differences between normal and battery saver mode are not described (other than to say that battery save mode saves 50% of the battery power and is "suitable for most applications". Velocity is allegedly limited to about 100 MPH, but there is no mention in the manual about it. Well, that's all for now. There are a number of other minor features but this should give you an idea. Overall, this is one of the niftiest gadgets I have ever seen, and definitely the best handheld GPS I have seen yet! Gavin Scott - gscott@netcom.com -or- gavin@denkart.com ---------------------------------------------------------------------- From: swest@as.arizona.edu (Steve West) Subject: Garmin GPS 40 features summary Date: 14 Sep 1994 15:59:26 GMT Here is a brief review of Garmin 40 features. I'm just a novice. Also, this is just a skim of the features. The unit provides all kinds of shortcut ways to do things. I have also missed several features in this review. The unit comes with a 60 page manual. It still has references to marine stuff, but for the most part, it provides general descriptions/instructions applicable to land or water use. ... STATUS AND POSITION PAGE: This page has a polar plot of satellites that are visible over your horizon. The display is "live" so the positions of the satellites change with time. They are represented by numbers. Below the polar plot is a space for 8 signal strength bar graphs. As a satellite is acquired, the number on the polar plot is changed from inverse to normal video, and a bar graph for the satellite strength is created. The bar graphs are shuffled as new satellites are acquired, or old ones move out of view, or the "lock" was lost. 3 satellites are required for lat/long and 4 to add altitude. It also estimates the horizontal accuracy of the result [based on the geometry of the aquired satellite locations -Editor]. It usually states an accuracy between 500 ft and 49 ft. Once the unit is set up for your location, it can usually acquire 5-7 satellites within a couple minutes after turn-on. It seems pretty insensitive to orientation. If it cannot maintain a lock on at least 3 satellites, it sends you an alarm saying poor GPS coverage. POSITION PAGE: The position page shows your current lat/long/altitude. There is a moving compass segment at the top that shows your current bearing if you are moving. It estimates your velocity too, and shows you the current time. NAVIGATION PAGE: This page shows an active course deviation indicator (CDI). It allows you to choose a waypoint target, and then you simply follow the roadway to your destination--this is really cool! It estimates your velocity and arrival time and a bunch of other things. It also provides a Man Overboard function (MOB). MAP PAGE: The map page plots a map of waypoints and your current course. You can zoom and pan the map. The waypoints are indicated with a square and the name you gave them as you inputed them. At any time, you can simply highlight a waypoint on the map and it will tell you the required bearing and distance to get to it. It does lots of other stuff too. MENU PAGE: This page allows selection of 11 menu systems: 1. Nearest waypoint list (shows 9 nearest waypoints). 2. Waypoint list (lists all waypoints and allows you to look at them in detail) 3. Waypoint (details of single waypoint) 4. routes (allows development of up to 20 routes with 30 waypoints each along with editing, copying, pasting etc. You can also specify preferences for waypoint summaries to show DTK, ETE, ETA, etc). 5. Distance and sun calculations (allows input of 2 waypoints for distance and bearing calculation and shows sunrise/sunset times at the destination waypoint). 6. Operation menu (allows selection of unit mode, time offset, LCD display contrast, backlight time, and tone/beep control). 7. Navigation setup (set up position display format, map datum format, CDI scale, units preference, magnetic headings). 8. Track and log setup (allows the unit to automatically make a log of your positions. You can set it up for time or distance intervals for auto data taking plus a bunch of other stuff). 9. Map setup. configure the map display with polar rings, show route or not, show names or not, select preference north up or track up etc, configure track log plotting). 10. I/O setup (configure I/O and differential GPS). 11. messages menu (whenever the unit sends you an alarm for one reason or another, it details the message here). MARKING WAYPOINTS: Marking waypoints is as easy as pressing the mark button. The current lat/long/time are stored. You can give the point a name and provide your own comments and put the point in a specific route number if desired. APPENDICES: A. Glossary of terms B. Messages possible on message page. C. Longitudinal time offsets [in hours] D. Map Datums E. Maintenance and Specs. F. Electrical wiring and interfaces. G. Installation of optional mounting bracket and I/O connector. H. Index swest@as.arizona.edu (Steve West) ---------------------------------------------------------------------- end reviews FIRMWARE (GPS 45/40 INTERNAL SOFTWARE) QUESTIONS: ------------------------------------------------- -Speed limit? There is an undocumented firmware speed limit of 90 Knots, 104 MPH, 167 km/h. Except for the compass and clock, all of the fields blank out above the speed limit. Thanks to John M. Lewis (70544.73@compuserve.com) for his well documented test with a laptop computer in a plane. His report is included below. Apparently the reports of 100 knots or 100 MPH limits were in error! This limitation has created a lot of debate in the GPS newsgroup primarily because it is not well documented and arbitrary. Recent reports indicate that it is mentioned very briefly in newer versions of the 40 manual. This was apparently done to prevent these models from competing with the aviation models that are priced at several hundred dollars more. An alternative way to look at it is that aviation unit purchases help to reduce the costs of our GPS 45/40 models! There is an aviation model called the Garmin GPS 90 that looks like the GPS 45 except that it has different firmware, a black case, and a couple of buttons are relabeled. Internally it may have better shielding and more battery backed up memory. Of course it does not have the speed limit and it has some other software features for aviation use such as a database of public airports and navigation aids. See below for more Garmin GPS 90 info. Because of the speed limit, some people have bought other manufacturers GPS units instead. Hopefully this speed limit will be removed in a future firmware version. Here is a report of the details by John Lewis: I took a GPS 45 into an aircraft, it worked OK up to and below 90.0 KTS. Above 90.0 nautical miles per hour it beeped with "Poor GPS Coverage" and did not display the track, speed, position, or altitude. The time and the "compass card" did display. The track map did not indicate the >90Kts points, nor did the track data download. Upon decreasing speed to 90.0 Kts, even if only for a second, the full display reappeared, with accurate position information. During the speed blackout, the sat status page indicated 8 satellites with nearly full signal strength bars. The GPS 45 was attached to an HP100LX palmtop for data recording. The following is an excerpt edited to pertinent RMC sentences: Garmin GPS 45 V2.32 NMEA V2 RMC sentences ID, UTC-GPS, LAT , LON , KNOTS,Track, Date $GPRMC,231109,A,3030.183,N,08819.149,W,087.2,284.8,140595,,*0E $GPRMC,231111,A,3030.203,N,08819.206,W,086.2,293.9,140595,,*02 $GPRMC,231113,A,3030.229,N,08819.257,W,089.3,300.4,140595,,*04 $GPRMC,231115,V,,,,,,,140595,,*38 $GPRMC,231117,V,,,,,,,140595,,*3A . . $GPRMC,231539,V,,,,,,,140595,,*32 $GPRMC,231541,V,,,,,,,140595,,*3D $GPRMC,231543,A,3032.451,N,08824.848,W,090.0,097.0,140595,,*06 $GPRMC,231545,V,,,,,,,140595,,*39 $GPRMC,231547,V,,,,,,,140595,,*3B . . $GPRMC,231643,V,,,,,,,140595,,*3C $GPRMC,231645,V,,,,,,,140595,,*3A $GPRMC,231648,A,3032.932,N,08824.232,W,086.7,277.8,140595,,*05 $GPRMC,231650,A,3032.915,N,08824.287,W,081.2,256.0,140595,,*0E Reconfiguring the 45 for display in Statute MPH, the display changed to dashes at speeds in excess of 104 MPH. When configured for Metric, the device becomes useless above 167 K/H. The ability to instantly relock and display correct data upon reducing speed to 90.0 Kts, as well as the ability to display correct heading via the compass card indicates a software induced blanking, not a hardware limitation. There may exist a hardware limitation at speeds in excess of 110 Kts, this test flight did not exceed 110 Kts IAS. John M Lewis <70544.73@compuserve.com> -GPS 90 info? I found the following press release which was posted several months ago. It contained lots of non-ASCII characters which I stripped out. Some more info from a recent posting follows. Start of press release: ---------------------------------------------------------------------- Subject: GARMIN introduces GPS 90 Organization: GARMIN International Date: Tue, 4 Apr 1995 15:25:38 GMT Essentially, if you know the GARMIN product line, this is a 40, a 45, and a 95XL all rolled into one package. FOR IMMEDIATE RELEASE: April 9, 1995 GARMIN Introduces Powerful GPS Receiver in Small Package The GPS 90, the world's smallest handheld GPS, is packed with all the features of its larger counterparts LENEXA, Kan. GARMIN International, aviation's leading GPS manufacturer, announces the introduction of the GPS 90, the world's smallest GPS handheld receiver. At only 10 ounces, and about the size of a remote control, the GPS 90 is full-featured, with moving map graphics, a large LCD display and an extensive Jeppesen database that includes all airports, runway diagrams and available navaids and SUAs, all at the pilot's fingertips. Significantly, battery life for the GPS 90 is approximately 15 hours on only four AA batteries, greatly exceeding that of any other GPS receiver to date. The ergonomic design of the GPS 90 truly is a breed apart from other models in the marketplace. Specifically, the GPS 90 is designed to fit comfortably in the pilot's palm for single-handed operation. Or, the unit mounts nicely in a universal yoke mount, which is an included accessory with purchase. The GPS 90's unique thumbkey rockerpad offers two scrolling speeds and quick, intuitive data entry. The GPS 90 will bring many pilots into the GPS fold for the first time, said Tim Casey, GARMIN's aviation marketing manager. Its size, simplistic software operation and amazing battery life make it the one piece of equipment every pilot's bag should make room for. The GPS 90 has a unique, rockerpad cursor control and only six function keys, enabling pilots to quickly access one of five main pages that are displayed on the EL backlit LCD screen. Those five pages are: satellite status, position, moving map, navigation and menu. The satellite status page shows which satellites the receiver is tracking, the strength of their signals, and also displays the battery power via a graphic fuel gauge. The position page indicates your track, speed, latitude, longitude, altitude and time-of-day. The moving map graphically plots your course as you mark waypoints and travel waypoint to waypoint. The map is capable of 12 range scales from 1/5th to 320 miles and will also zoom and pan the area you're navigating. Pilots may also view airports, VORs, NDBs, SUAs and other user-chosen information provided by the internal Jeppesen database. The navigation page indicates your bearing, distance, track and speed to an active waypoint. A course deviation indicator tells you when you're off course. The menu page offers pilots various setup and user-preference options, an E6-B menu, sunrise/sunset calculations and route and waypoint management features. GPS 90 users may also choose to operate the unit at home in the simulator mode to plan trips, customize user options and enter or modify waypoint and route information. The unit will store 250 user-defined waypoints and up to 20 reversible routes, with 30 waypoints each. Additionally, the case for the GPS 90 is ultra-sonically welded and dry-nitrogen filled. The GPS 90, along with the entire GARMIN product line, relies upon GARMIN's proprietary MultiTrac8 receiver technology, which tracks and uses signals from up to eight satellites simultaneously. The GPS 90 comes with a carrying case, user's manual and quick reference card, wrist strap, universal yoke mount bracket, suction cup antenna mount, power-data cable and a cigarette lighter adapter. Optional accessories available for purchase include a serial data cable and PC kit. The GPS 90 is currently available and lists at $799. GARMIN International designs, manufactures and markets GPS equipment for a variety of markets, including aviation, marine, military, survey, OEM and general recreation. For more information on the GPS 90 or any of GARMIN's other GPS receivers, contact GARMIN International, 9875 Widmer Road, Lenexa, KS 66215; phone: (913) 599-1515 or FAX (913) 599-2103. ---------------------------------------------------------------------- End of press release Here is a some info about the GPS 90 all supplied by Roger Vermeir (meirr@btmaa.bel.alcatel.be): Controls are the same, except for some key labels: 'GOTO' on the 45 is called 'GOTO NRST' on the 90 'MARK' on the 45 is called 'WPT' on the 90. Here are some specs of the 90: up to 250 user waypoints; up to 20 reversible routes (with up to 30 wpts each) acquisition: warm approx. 15 sec (I've had several in less than 8 sec, in good conditions) cold: approx. 2 min autolocate : approx. 7.5 min (but it may need up to 15 min, and if you are in a real 'Poor GPS coverage' area, it will start beeping and then auto shut-off) update rate 1/sec (cont) accuracy: position: 15 m (49 ft) RMS (10 m 2DRMS if DoD's SA is ON) velocity: 0.1 kts RMS steady state Dynamics: 999 kts velocity, 3 G's Interfaces: NMEA 180, 182, 183, unit-to-unit, PC, RTCM 104 v.2.0 (corrections) MAP datums : 105 size: 6.15 x 2 x 1.23 inches (15.6 x 5.1 x 3.1 cm) weight: 9 ounces (255 g) inclusive batteries display: 2.2 x 1.5 inches (5.6 x 3.8 cm) high contrast backlit LCD case: ultrasonically welded, dry nitrogen filled power: 4 AA batteries or 8...40 V DC 0.75 W max consumption Temp. range : 5 F to 158 F (-15 C to + 70 C ) Battery life: up to 15 hours (normal mode) or 20 hours (battery saver mode) Built-in rechargeable lithium battery saves almanac and waypoint data while you are changing batteries, BUT WILL ONLY SAVE DATA FOR A FEW MONTHS (according to the Garmin manual). Roger Vermeir (meirr@btmaa.bel.alcatel.be) -GPS 45/40 Firmware versions: The firmware is believed to be identical between the 2 products except for the strings "45" & "40" (which could still be in the same EPROM). V2.02 4/94 Early release of GPS 45 ... V2.24 ... V2.32 Shipped for quite a while V2.40 5/95 New feature: Fuel Gauge gone when connected to external power V2.41 6/95 Has simulator random power down problem (minor) V2.42 7/95 Fixed simulator random power down problem The above dates are approximate within about 1 month. The only way to update your firmware is have the unit serviced at Garmin's $149 flat rate fee for repairs. It is not a trivial operation. See the section "Internal electrical hardware" for the details of the EPROM replacement. I have not heard of any serious bugs in past versions so it is very likely not worth upgrading. -Are there any undocumented modes? Globe spin rate and direction: Go to the map display. Then press the OFF button for 1-2 seconds. The globe will still be on the screen and you can change the speed with the up/down buttons and the direction of rotation with the right/left buttons. Press any button to return to normal mode. Test screen: Hold down ENTER while pressing on the POWER button. Invokes button test screen & displays labeled SNR, drift, freq, temp (Celcius), Battery (in hundredths of Volts). Press ENTER 2 times to get an all black screen, press ENTER again for cool exploding rectangles on the display. Hold down OFF button to exit this mode. Also turns beep on if you had it off! Full reset and memory clear: Hold down MARK while pressing on the POWER button (CLEARS MEMORY!!!). DON'T TRY THIS UNLESS YOU ARE WILLING TO LOSE ALL SAVED INFO!!!!!!!!!! Waypoints, Track, Routes and more will all be gone. I wouldn't do this unless my GPS unit was having serious problems (and then only as a last resort attempt to fix it before sending it in for repair)! POWER/BATTERY QUESTIONS: ------------------------ -How is power selected between the internal batteries and the external supply? Apparently current is drawn from the supply with the higher voltage (internal, not input). If neither is high enough, the unit will shut off to allow the memory to be maintained. -What voltages do the fuel gauge correspond to? I hooked up a GPS45 to a variable supply in the shop and found the following in testing the battery monitor display. Ext DC, no batteries in unit. [for firmware < V2.40 only, newer versions do not display the fuel gauge for external power to allow you to know when you are draining the internal batteries. -Editor] Full reading ~6.5v 3/4 ~6.2v 1/2 ~5.8v 1/4 ~5.4v Empty ~5.3v low battery alarm, unit turns off DC supplied thru battery compartment [believed to be true for all units -Ed.] Full reading ~5.65v 3/4 ~5.3v 1/2 ~5.00v 1/4 ~4.6v Empty ~4.25v low battery alarm, unit turns off Readings did not exactly repeat and there appeared to be some hysterisis, hence the tilde. Unit transitioned smoothly between external dc and internal batteries when external power was cycled (unit did not lose sat lock). On external power, the unit would not keep running unless the voltage was 5.4v or better. It would turn on, give the low voltage message, then go off when under 5.4v. davew@cruzio.com (David Wells) -How does BatterySave mode work? According to Garmin's Tech Support Department- These are a couple of the things the saver does: 1. Stops the unit from trying to re-lock if it loses the birds. 2. Cycles the receiver off and on periodically if you are motionless. (update time) (Ralph Fowler rwf@mindspring.com) However, most people feel that the BatterySave mode offers only a small battery life improvement in general use but it doesn't hurt to keep it in that mode. There has been suggestions that the BatterySave mode works best when you are on a straight steady route. It probably does worst when carried by a hiker because of the erratic movement. -Battery Options? Nickel Cadmium batteries are much cheaper than alkalines long term if you use your unit a lot and can conveniently recharge them. Unfortunately the battery life is only about 3.5 hours per charge instead of 10 hours for alkalines. Also, the fuel gauge gives a less accurate state of charge for NiCd batteries because they have a more steady voltage over their discharge cycle instead of the gradually decreasing voltage of alkalines. You could also use Ray-O-Vac Renewal batteries which are rechargeable alkalines. They are only rated for about 25 recharges (compared with approximately 1000 recharges for NiCd batteries) but would likely have a longer life per charge and a slower self discharge rate. Also, the fuel gauge would read more accurately. Of course an optional cord could be used if you have some other DC power available at the appropriate voltage such as in a car or boat. Some people have also hooked the optional cord into a battery pack that could supply power for days of use. -How long is the memory conserved without batteries? One report indicated at least a week. I have not heard reports of erased memory when changing batteries. -Does the serial I/O draw much power when it is enabled? I have [measured the current consumption] with the 45,50, and 75 and could see no change measuring down to +/- 1mA. So if it does it is negligable. tmiller@umabnet.ab.umd.edu (Tom Miller) I tested the GPS 40 and it too does the same. davew@cruzio.com SERIAL/POWER INTERFACE: ----------------------- -External Serial & Power Connector alternatives? Garmin uses a non-standard 4 pin (for GPS 45) round connector (a center pin is added for the GPS 40). I personally recommend buying the cable with the correct connector from Garmin. Garmin sells a data/power cable for the GPS 45 with the rare connector and 4 wires for about $30 list. I feel that building your own cable is a little risky because of the possibility of mis-indexing the connector which could damage the unit. Also, there is a risk of intermittent operation due to the mismatch with pin/socket size if you don't replace the pins (been there, done that!). Some people have substituted a 5 or 8 pin DIN connector for the GPS 40 or a 4 or 7 pin DIN connector for the GPS 45. There are several pin arrangements for the DIN connectors (even with the same number of pins!). You should plug any unused holes and if you are using the DIN sockets (not as reliable), you should bend the sockets in to improve the reliability of the contact with the smaller pins of the GPS 45/40. You also should wrap the connector with tape and then heat shrink tubing (preferred over tape alone) to bring it out to the correct diameter. The pin out is in the appendix in the manual. Here is a much better design (using Radio Shack parts) for a home built cable by Rane Curl: The connector for the Garmin GPS 40/45 has been the subject of a number of inquiries since I last posted my description of how to make one. It is easy and inexpensive. Here are instructions: 1. Remove sockets from RS-274-001 4-pin mike connector and drill out holes (1/8"). Drill 5/64" hole for center post (GPS 40). Wrap with (2 turns) tape (for snugger fit), and cut out tape at key. 2. Solder (or crimp) D-Sub socket-pins on cable wires. Put plastic (heat-shrink works) tubing on socket-pins and insert them in connector holes. Fix them in place temporarily with pieces of plastic tubing pushed in from ends so as to press socket-pins outward (bolt-circle of GPS pins is larger than that of connector holes). 3. Insert connector into GPS body and push socket-pins down onto GPS pins. Apply epoxy resin (ca. 3 drops) to inner ends of socket- pins (too much could run too far down and ooze out end - the tubing that was pushed into the holes helps prevent this). 4. After epoxy is set, tighten cable clamp to cable, wire cable to computer/power interfaces, and enjoy. Rane L. Curl N8REG ranecurl@engin.umich.edu There are at least several optional power cables available from Garmin. Some are data only, power only, and both. You must supply the appropriate connectors for the other end on the cable that has both power and data. There is even a Garmin to Garmin transfer cable so that you can upload the stored data from one unit to another. See the accessories list elsewhere in this FAQ. -How do I interface the GPS 45/40 to an IBM-PC compatible computer? Garmin DB-25 DE-9 Func color* pin pin ---- ------ ----- ---- data in white 2 3 data out brown 3 2 ground black 7 5 power in red N/A N/A (for ext. power only, don't forget to add a fuse!) *Garmin 45 manual, Appendix F Unfortunately, to connect to an IBM-PC compatible, you will need one of two different connector types. The old serial standard (which was also used on the original IBM-PC) was a DB-25 type connector. Newer computers may use DB-25 but most often use a DE-9 connector. You need a female DB-25 or female DE-9 connector to plug into your PC. To find out which, count the number of pins on the serial port you plan to use (on the back of your computer). It should be either 9 or 25 pins (not sockets) indicating which of the 2 types of connectors above you need. Apparently the NMEA spec is now for 0V and +5V, but it used to be +/-15V and protection is supposed to be included in newer instruments to prevent damage by the over voltage. Unfortunately, I have not yet seen a copy of the NMEA 183 spec. Apparently the (0 to 5 V) GPS 45 & 40 have protection for the IBM-PC compatibles +12 and -12 V RS-232 levels? I called Garmin technical support and was told that the serial port is for 0 V and 5 V levels only and they do not recommend connecting it to a connector with different voltages (ie. most PC's). I found this hard to believe so I called back several days later and got a totally different answer. This time I was told that I could directly connect to PC's and that the port could handle the +12V and -12V just fine (which is apparently more in line with the NMEA 183 spec). It sounds like they need some more training! I haven't heard anything concrete to the contrary, so apparently you can just connect up the 3 wires to the PC serial port. If it damages the GPS, I guess that what warranties are for (in the first year anyway). -How do I interface the GPS 45/40 to a Macintosh? You can download the following file from Peter's ftp site (address in the section "GPS 45/40 ftp/www sites": NMEA_INTERFACE.TXT by Lorne Dudley (dudley2@qucdn.QueensU.CA) shows a circuit to interface a Garmin GPS50 to a PC or Mac serial port. It is probably not needed with most PCs, but may provide a more "correct" interface. It should work with most GPS receivers having NMEA inputs and outputs. -Internal electrical hardware? Somebody bravely took apart their GPS 45/40 and they described the IC's. Several other people tabulated the data and identified more parts. I ran a component database search and was able to find a few more. It would be helpful if somebody could identify the manufacturers logos on the unidentified IC's and provide any other info about them. Manuf. Part No # pins Function INTEL TS80L188EB13 80 CMOS 80188 cpu ATMEL AT27LV020 32 3.3V 256k x 8 (2Mb) EPROM (Surf. Mount, no window) DALLAS DS1202 8 serial timekeeping chip MITS M5M5256CVP 28 32K x 8 SRAM PHILIPS SA626DK 20 FM IF amp,det,limtr,mixer,osc GARMIN 80-00003/420100 44 ?????? ? 532 / A18 8 ? ? 5W393 8 ? ? 7WU04 8 ? PHILIPS 74LV373 20 3.3V octal 3-state latch PHILIPS 74LV373 20 3.3V octal 3-state latch PHILIPS 74LV00D 14 3.3V CMOS quad NAND various 74HC4040D 16 ripple 12-bit bin up counter The analog section has a device labeled "Garmin 5900000201, ?? : IBM14R1608,64G0203" in a 44 pin package. ???? The EPROM is a surface mount non-socketed part. Contrary to some initial reports, the firmware doesn't appear to be in flash memory. (Flash memory would be of interest because they are re-programmable without removing the part from the board). The fact that the firmware appears to be in EPROM, explains why it costs so much for a firmware upgrade (not that an upgrade is necessary). It would require opening the case, desoldering the surface mount EPROM, resoldering the new one, testing the unit, replacing the case, filling the case with nitrogen and resealing it. -What computer software is available to communicate to the Garmin GPS? There are 2 general ways that software can communicate with the Garmin GPS units: 1) Use one of the NMEA 183 software protocols that handles communication between most NMEA 183 instruments such as autopilots, lorans, compasses, etc. Garmin has some additional unique commands which are useful. 2) Use Garmin proprietary format that allows you to upload and download waypoints, track info, and routes. Here is a list of the Garmin specific programs: Garmin's official software: Garmin PCX5 software including cable with DE-9 connector* ($150). MS-DOS based. Upload, Download, edit, graphically plot waypoint, route, and track log files. Creates a moving map as you travel. Creates satellite visibility charts. Reports are that it is a pretty good program, but the graphics are slow on older PC's. * I understand the cable is just a 3 wire connection to the GPS unit with no other circuitry or PC handshake lines tied back. Is this correct? Could someone measure the resistance between the DE-9 connector pins (without a PC or Garmin attached). This would give us more confidence in recommending a direct connection interface using the $25 cable. Fortunately several people have generously written several other much less expensive programs for our benefit: MacGPS-45 (Macintosh freeware): A Mac specific program for the GPS 45/40. GARDOWN (freeware): A simple but effective DOS program that downloads and uploads Waypoints, Track data, and Route data. Use this program before the Windows programs because it is much easier to troubleshoot any serial/cable interface problems. GARMIN by Peter Aigner (freeware): A Windows program written in Visual BASIC to upload and download waypoints, track info, and routes. The main file is called WINGARMN.ZIP and it should include the files GARMIN.ZIP and GARMINA.ZIP among others. GARMIN65.NMEA Prepared by Peter Bennett (bennett@triumf.ca) is an annotated listing of NMEA sentences sent by a Garmin GPS-65. The GPS 45/40 should be similar. GARMAP.ZIP (from mholdern@sctyhq1.telecom.com.au) provides an interface between Mapinfo Desktop Mapping Software and a Garmin GPS receiver, using the proprietary Garmin/Garmin protocol. Don't forget you may have to set your GPS 45/40 "I/O SETUP" to "GRMN/GRMN HOST" or the above programs may not will work in Garmin mode. GMN_DXF1.ZIP (from DNelson@lanl.gov) converts the data downloaded by GARDOWN into a .dxf file for import into AutoCad or other drawing programs that read this format. WINGPS by Jos Verbeek(): A Windows program written in Visual BASIC that talks NMEA but has some Garmin options. It works with the same datafiles used by the utility GARMIN. Here is some info I got via E-mail from DCOLE@alb.asctmd.com: All of this S/W is DOS based which means it can even run on the HP100 or 200 palmtop computers. "GPSDASH" Reads the NMEA data strings from the GPS and shows on the screen in very large readable letters and gauges Speed, Max Speed, Elapsed Time, Distance , Total Distance, Heading, Altitude, Max Altitude, DOP and Satellites in use. This S/W also logs to a file so that an infinite number of track logs can be stored. This file saved can be replayed on "GPM-PRP" mapping S/W (see below). Price is $30.00 "GPSXFER" connects to the GPS45 and Downloads track logs and Uploads/Downloads Waypoints. This S/W will also work with most other models from GARMIN. Price is $30.00 "GPM-PRO" is a real time mapping S/W package which can be used to plot a trace of the GPS activity and can then be used as an overlay on maps. This is a feature rich piece of software which has almost all the capabilities ever needed for mapping. This program will hotlink to "GPSDASH". Price is $249.00. The 3 above programs can be obtained from "Cole Enterprises" at 505-856-7402 614 Cedar Hill Rd NE Albuquerque , NM 87122 -GPS 45/40 ftp/www sites? Garmin's software is available though their dealers. Peter Bennett has an excellent ftp site and WWW page which have the rest of the freeware/shareware programs above: ftp to "sundae.triumf.ca", cd to /pub/peter or web address "ftp://sundae.triumf.ca/pub/peter" Tim Hogart has some internal hardware information on his Web site: http://inmind.com/~thogard Larry James has inherited the MacGPS_45 software originally by John Waers: ftp://ftp.hawaii.edu/mirrors/info-mac/sci/larrys-mac-gps.hqx ANTENNA QUESTIONS: ------------------ -How is the GPS 40 antenna internally constructed? It is called "patch antenna". The same type is used for the 40 external antenna. Need more info! -How is the GPS 45 antenna internally constructed? Thanks to a friend (Mike Petterson) whose GPS 45 antenna case split, we were able to examine the antenna construction. It is a quad-helix circular polarized antenna. It basically looks like a double sided flexible circuit board rolled into a about a 1/2 inch diameter cylinder. It has 4 spiral elements like the stripes on a candy cane. It is definitely a passive (non-amplified) antenna which works pretty well. Some people have disected their antenna's and scanned in an image of it. Location??______________________________________ -How well does the internal antenna work inside a car? You can use a GPS unit on the dash of your car with the normal antenna but the roof of the cars shields about 1/3 of the satellites. I typically get 4-6 satellites (adequate) on the open road and less when between buildings. You can get much better reception with an external antenna on the roof. -What are the remote antenna options? GPS 45/40: There are several basic approaches to external antennas: 1) Use the existing non-amplified antenna and insert a short piece of coaxial cable between the connectors. With this approach, you only have to pay for a coaxial cable extension and perhaps a gender changer. 2) Buy (or build) an external antenna. If the coax is going to be longer than several meters, then you need to use an amplified antenna to overcome the signal losses in the coax. The Garmin (45 at least) supplies 5 V to the coax connector. The satellite signals are severely attenuated by coaxial cable at the GPS civilian frequency of 1575.42 MHz. If the original (non-amplified) antenna is used, the length should be kept less than several meters. Garmin sells a couple of mounting options that use suction cups or magnetic mount antenna bases that work pretty well. GPS 40 antenna connector info: The Garmin GPS 40's antenna connector is called an MCX connector. One primary manufacturer of these connectors is: Huber & Suhner Inc. One Allen Martin Drive P.O. Box 400 Essex, VT 05451 One of the representatives (who sent me their 1" catalog of RF connectors) is: C.W. Swift & Associates, Inc. 15216 Burbank Blvd, Suite 300 Van Nuys, CA 91411 (818) 989-1133 (818) 989-4784 (Fax) (800) "MICROWAVE" -> 642-7692 Keith Huie GPS 45: You can buy a SHORT coax extension and mount the antenna on the inside of your windshield or sunroof. Radio Shack sells several 6 foot RG-58/U coax extensions with two suction cup mounts or a window mount for about $11. I have had partial success using this with a sunroof. You can also buy the coax alone for less but you will need a BNC gender changer. The 6 ft of RG-58/U (a very lossy coax at these frequencies) drops the signal strength approximately 2 units (out of 5) on the signal strength display. I have not yet taken the time to calibrate the signal strength indicator in dBs. You can also get a 90 degree BNC elbow to allow better orientation of the antenna. -Can I make my own external antenna? Yes. You should have some RF and antenna knowledge before diving into this project (at least until we can get some more detailed instructions). I am working on one now. Look at the Satellite Experimenter's Handbook (ARRL) for some antenna info. There are also two articles that have been posted that have some good info but don't provide enough detail for you to construct an external antenna from them alone. Source??__________________________________ A GPS antenna needs to be carefully selected at this frequency because antenna tuning is very difficult and a hemispherical radiation pattern is desired for GPS satellites. If the coax is longer than several meters, you will likely need an amplifier to overcome losses in the feedline. Several people have suggested the Mini Circuits MAR-6 amplifier which looks like an excellent choice because of its low voltage, low current, high gain at 1.5 GHz, and its simplicity. It only costs about $2. I read that Ma/Com also makes a GPS preamplifier ($8) which is designed for this application but much harder to obtain. Based upon information in the spec sheets for coaxial cable, I think RG-6 (75 ohm) coax is the most attractive from a standpoint of loss and flexibility but it is not 50 ohms. Another poster independently came to the same conclusion. The losses due to a impedance mismatch would likely be less significant than the attenuation of the cable (at least for longer runs). Even Garmin uses RG-59/U coax (75 ohm) on one of their external antennas. MISCELLANEOUS: -------------- -GPS Mounting options? Garmin sells a very nice swivel clamp bracket for about $35. (It used to be included w/ the GPS unit but they lowered the price and removed it and a cable.) There are other companies that make GPS mounts, ham radio mounts, and cellular phone mounts for less money but they are not as nice as Garmin's. Velcro (tm) adhesive strips (available at Radio Shack) work out well for use in some locations and can't be beat for cheapness. -Waterproofness: The GPS45/40 is considered "waterproof" but everybody's interpretation of waterproof is different. It is also filled with nitrogen to prevent the screen from fogging. Several people have reported leaks resulting in fogging but it was covered by Garmin under the one year warranty. A marine electronics design engineer pointed out that it is difficult to make electronics truly waterproof due to changes in pressure due to temperature. I would minimize submerging the units although they should easily be able to take splashed water. Several people have reported that the BNC connector is not that well sealed and may be a weak link. This probably wouldn't be a problem with the GPS 40. Someone else pointed out that you should grease the GPS 45 antenna connector before exposing it to salt water to prevent corrosion. -Case? The case that now comes with the unit is strictly a carrying case and the unit is not usable when it is in it. Garmin apparently has a case that you can use to protect the unit while you are actually using it. I haven't seen it and don't know if it floats. West Marine has a yellow neoprene rubber "floating" padded carrying case with a clear plastic window (for use of the buttons and display) and their name printed on it for $10. It looks like it is designed for the GPS 40. The GPS 45 is a little tight around the antenna connector where the antenna hangs off so you have to careful how you swing the antenna, but is still useful. A good investment in my opinion. I have heard reports that they are hard to locate but I have seen them in stores recently. -Garmin accessories? GP40 part number Item description list price GA27 Low Profile remote ant w/8ft cable $ 160.00 MCX connector & magnetic/suction mount 010-10061-00 Trunk lip mount GA 26/27 18.95 010-10062-00 Flange mount GA 26/27 18.95 011-00152-00 Suction cup mount GA 26/27 18.95 011-00153-00 Magnetic antenna mount GA 26/27 25.00 320-00048-00 8 ft extension cable GA 27 40.00 4015 GPS 40 carry case 35.00 4040 GPS40/45 Cross load cable(unit to unit) 50.00 4041 GPS 40/45 PC Interface cable 30.00 4042 GPS40 data cable 25.00 4050 GPS 40 cigarette lighter adapter 50.00 4514 GPS 40/45 PC Software and cable kit 150.00 4518 GPS 40/45 mounting bracket 45.00 GPS 45 GA 26 low profile remote ant w/magnetic/suction cup with 8 ft cable BNC connector 160.00 320-0049-00 8 ft extension cable for GA 26 40.00 GA 28 low profile remote marine ant w/30 ft cable and BNC connector 160.00 010-10067-00 GA 28 flange mount kit 22.00 1011 Marine/RV remote ant w/30 ft cable BNC 160.00 1013 30 ft low-loss ant ext cable w/connectors 115.00 1028 Magnetic mount ant with 10 ft cable 160.00 4522 GPS 45 handheld/portable ant 100.00 GPS 45-000 Portable antenna 495.00 GPS 45-100 Portable antenna Marine/RV remote mount 655.00 GPS 45-200 Portable antenna, Magnetic mount antenna 655.00 5519 Remote antenna mount: suction cup/screw mount w/ 6ft cable BNC 40.00 4040 GPS 40/45 Crossload cable (unit to unit) 50.00 4041 GPS 40/45 PC interface cable 30.00 4514 GPS 40/45 PCX5 Software and cable kit 150.00 4515 GPS 45 carrying case 35.00 4518 GPS 45 mounting bracket 45.00 4520 GPS 45 power/data cable 30.00 4550 GPS 45 cigarette lighter adapter 25.00 Disclaimer: These prices may not be current list check around and see if deals exist Sid wa2fxb@ix.netcom.com ( a buyer not a dealer, stockholder and have no vested interest in Garmin) -Can I use my GPS in a plane? You must first have the pilot's permission. It is possible that the GPS unit could interfere with the navigation/communication systems. This does not usually happen, but it could. This is true for many electronics, especially if they involve a radio receiver (which is part of a GPS unit). Of course, the GPS 45/40 will not work above 90 knots anyway so it would only be useful on a slow plane or most gliders. -Performance in trees? GPS reception is always difficult in trees. The attenuation depends on the density of the canopy, and how much moisture is in the leaves. If the canopy is too dense (pretty common in the forest), you may have to find a clearing to get a fix. The GPS 45/40 reportedly does not perform quite as well as a few other units when surrounded by trees. This is because the GPS 45/40 is sequencing receiver that sequences between 8 channels instead of having 8 continuous channels like some other units. Continuous receivers are able to track more marginal signals at once. However, they cost more, are larger, and don't have the battery life of a sequencing receiver such as the GPS 45/40. Isn't the GPS 45/40 a 2 continuous channel, 8 sequencing channel receiver? I don't see it documented anywhere. -Other Garmin GPS PORTABLE models? This is a chart I constructed. It may not be absolutely accurate! MODEL USE YEAR SPEED LIMIT ----- --- ---- ----------- GPS 40 marine, hiking 1994 90 knots GPS 45 marine, hiking 1994 90 knots GPS 50 marine, old, replaced by GPS 75 ? 90 knots? GPS 55 aviation, old ? No GPS 75 marine 1992? 90 knots? GPS 90 aviation, similar to GPS 45 1995 No GPS 95XL aviation ? No -Where can I purchase a unit? Garmin should be able to locate a local dealer: GARMIN International 9875 Widmer Rd. Lenexa, KS 66215 Phone : (913) 599-1515 Toll Free : (800) 800-1020 Fax : (913) 599-5263 Many marine supply stores carry the GPS 40 and 45. They are both priced at $500 list, but about $300 discounted in the US. Here are some often mentioned sources for Garmin products: West Marine 800-538-0775 or 408-728-2700 Cabellas 800-237-4444 E&B Marine 800-533-5007 Larry James of James Associates E-mail: lwjames@ix.netcom.com (Larry is knowledgeable about Garmin units and often answers questions in the GPS newsgroup) ---------------------------------------------------------------------- Repeating: I am not affiliated with Garmin or any of their retailers. This document is not in any way endorsed by Garmin International. I am only a satisfied customer. Please send CONSTRUCTIVE suggestions to: Lane Alan Holdcroft klah@eskimo.com KE7UT