From mujibur.inmind.com!uunet!in1.uu.net!eskimo!klah Tue Sep 19 09:45:01 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 45/40 FAQ, new version! X-Nntp-Posting-Host: eskimo.com Message-ID: Keywords: 40 45 90 100 faq garmin speed limit diag Sender: news@eskimo.com (News User Id) Organization: Eskimo North (206) For-Ever Date: Tue, 19 Sep 1995 06:31:36 GMT Lines: 1949 Garmin GPS 45 and GPS 40 Frequently Asked Questions =================================================== V 1.05 (Sep 18, 1995) This document is not in any way endorsed by Garmin International. I am not affiliated with Garmin or any of their retailers. 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. Much of this information applies to the GPS 90. Some of this information applies to other Garmin models as well. | This FAQ is based on my experience 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). Because I am an electrical engineer, I 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 maintained by Peter Bennett. It is available on his excellent ftp site as listed under "GPS 45/40 ftp/www sites?" in this FAQ. I will always post the latest version of this Garmin FAQ there also. | Because of the large number of questions that are still posted to the newsgroup that have been answered in this FAQ, I am trying to post this approximately once per week to the GPS newsgroup (sci.geo.satellite-nav). 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 individual questions not pertaining to the FAQ. However, I do read all feedback and do take note of it. I do read the newsgroup regularly but occasionally I do miss something Garmin related. A fair amount of the information posted about the Garmin units in the GPS newsgroup is wrong. I have spent a lot of time trying to make this document error free, but there is no guarantee to the accuracy of this information! Thanks to the many people who have contributed to this document! I tried to give credit to the original author at the end of the contribution. If an answer does not have an attribution, then I usually answered it based on my recollection of previous postings or my personal experience. If I felt clarification within another person's quoted material would be beneficial, my comments were contained within brackets "[" and "]". Copyright 1995 by Lane A. Holdcroft. Original contributors also retain their copyright for all of their contributions. Feel free to copy this in its entirety, but not for monetary benefit. If only a portion of this document is quoted, please give the original author credit. | FAQ Revision History: Ver Date Major changes --- ---- ------------- 1.00 Aug 4, 1995 Initial release 1.01 Aug 7, 1995 Minor corrections 1.02 Aug 20, 1995 Added detailed speed limit info Added GPS 90 info Added more detailed list of specs Added Garmin accessory list 1.03 Aug 22, 1995 Minor corrections 1.04 Aug 29, 1995 Added Garmin 45/40 wish list Added section head numbers Added GPS 45 external current consumption Added FAQ revision history 1.04a Aug 31, 1995 Very minor corrections 1.05 Sep 18, 1995 Added info about "Diag mode" Added info about Accuracy Added info about Garmin differential receivers Added "|" to indicate major changes in paragraph Reordered several sections Split out application software into its own heading Many minor corrections PLEASE DESTROY ALL PREVIOUS VERSIONS! This is more accurate than previous versions! FUTURE FEATURES: Split FAQ into 2 parts or reduce size to under 64K. Simple explanation of GPS, time, S/A, and differential receivers and how accuracy is affected. 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. Also, please include the version of the FAQ and the firmware version of your GPS 45/40. There is often conflicting information and your detailed references are valuable for resolving those discrepancies. Please send CONSTRUCTIVE suggestions to Lane A. Holdcroft (klah@eskimo.com) TABLE OF CONTENTS: ================== 1.00 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? -What is the accuracy of GPS? | -What is the Garmin differential receiver? | 2.00 SPECIFICATIONS/REPORTS: -GPS 45/40 specifications? -GPS 45/40 reports/description? -GPS 90 press release/specs? 3.00 FIRMWARE (GPS 45/40 INTERNAL SOFTWARE) QUESTIONS: -Speed limit? -GPS 45/40 firmware versions? -Are there any undocumented modes? -Why is internal temperature available? | 4.00 BATTERY/POWER QUESTIONS: -How is power selected between the internal batteries and the external supply? -What voltages do the fuel gauge correspond to? -Current draw of a GPS 45 at different external supply input voltages? -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? 5.00 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? 6.00 APPLICATION SOFTWARE: | -What computer software is available to communicate with the Garmin GPS? -GPS 45/40 ftp/www sites? 7.00 ANTENNA QUESTIONS: -What is the GPS 40 internal antenna? -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? 8.00 MISCELLANEOUS: -GPS mounting options? -Waterproofness? -Cases? -Garmin 45/40 wish list? -Can I use my GPS unit in a plane? -Performance in trees? 9.00 GARMIN AVAILABILITY: -Other Garmin GPS models < $1000 US? -Garmin accessories? -Where can I purchase a unit? ---------------------------------------------------------------------- QUESTIONS AND ANSWERS: ====================== 1.00 GENERAL FEATURES: ----------------- -What are the key features of the Garmin GPS 45/40? Generally true for all manufacturers' GPS units: 100 meter horizontal accuracy, 150 meter altitude accuracy 95% of the time. Velocity and heading information (and distance to a waypoint). Accurate clock when locked on satellites. Garmin GPS 45/40 specific: Relatively inexpensive (list $500 US, discounted $300 US). Long (10 hour) battery life w/ 4 AA alkaline batteries. One of the most compact units available . Neat graphical track log feature. Easy to use due to a simple menu system. Very feature rich. Water resistant. 64 x 100 pixel graphical display. Over 100 mapping datums used around the world. -What are the disadvantages of the GPS 45/40? 1) There is a firmware speed limit of 90 (nautical) knots (see "Speed limit" question elsewhere in the FAQ for more details). 2) Some options are more expensive than some competitors. A replacement 45 antenna is $100 and external power and/or data cables are between about $22 and $50. 3) 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 is not as fast as using a keypad. (The GPS 75 is somewhat wider but does have a full keypad). 4) The display is small because it is limited by the size of the entire unit. This is a compact GPS unit! If you have good corrected vision, it should not be a problem at arms length. -What are the differences between the GPS 45 and GPS 40? 1) The GPS 40 has a compact (quad-helix) 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 which is 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 a lot of 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. This is generally true of all quad-helix antennas. 2) The GPS 45 takes a much wider range of input voltages (up to 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 tape on its operation. -What is the accuracy of GPS? | Note that all position accuracy specs for the GPS are based on 95% DDRMS. Horizontal accuracy: 100 meters Current normal accuracy (Selective Availability ON) 18 meters Theoretical accuracy (Selective Availability OFF) 10 meters Differential accuracy (regardless of Selective Availability) Vertical accuracy (altitude): Approximately 1.5 times worse than horizontal accuracy depending on geometry of acquired satellites. In fact, you can get better vertical accuracy with an altimeter (but they must be adjusted for changes in barometric pressure). -What is the Garmin differential receiver? | In the US, the Coast Guard is in the process of setting up differential beacons to transmit correction signals. They are usually broadcast on existing marine beacon frequencies around 300 KHz. Many areas along the coasts already have them set up. Garmin sells an optional differential receiver called the GBR 21 (list $800, discounted to about $500). It is an external box much bigger than the GPS unit itself that requires external power and a antenna. It connects to the GPS 45/40. It compromises the portability of the unit but increases the accuracy to 8-10 meters as shown above. Some other manufacturers' differential units can be used but they can not automatically tune the frequency of the differential receiver as Garmin's can. There are probably some other differences also. 2.00 SPECIFICATIONS/REPORTS: ----------------------- -GPS 45/40 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 [0.284 kg] w/ batteries. Temp Range: 5 to 158 degrees F [-15 to +70 degrees C] 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 [95% of the time] under the DOD imposed Selective Availability Program (note: I average 150') Velocity Accuracy 0.1 knot RMS steady state [several knots error w/ SA] 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 ---------------------------------------------------------------------- -GPS 45/40 reports/description? Here are 2 good reviews that were posted last year. One is from a 45 owner, the other from a 40 owner. Keep in mind that other than the antenna and input voltage range, both units are IDENTICAL and most comments apply to both. I have included their reviews 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. >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] 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 SA), [100 Meter accuracy with 95% confidence (with SA on, as is the case now)] 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 (discounted to $500) 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]. 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 indoors]. 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 acquired satellite locations]. 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 input 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 [from manual]: 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) ---------------------------------------------------------------------- -GPS 90 press release/specs? I found the following press release which was posted awhile ago. It contained lots of non-ASCII characters which I stripped out. Some additional info and specifications from a recent posting follows the press release. Also, the Jeppesen database should be updated regularly for aviation use and the cost is over $100. 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 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 supplied by Roger Vermeir: 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 (100 m 2DRMS if DoD's SA is ON) | velocity: 0.1 kts RMS steady state [several kts realistically because SA is ON] | 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) 3.00 FIRMWARE (GPS 45/40 INTERNAL SOFTWARE) QUESTIONS: ------------------------------------------------- -Speed limit? There is a firmware speed limit of 90 Knots, 104 statute MPH, and 167 km/h. Except for the compass and clock, all of the fields are not displayed above the speed limit. There is no doubt that this is a firmware (software) imposed limit. One problem for Garmin might be that if they were to eliminate the 90 knot limit, how would they handle upgrades for existing customers? Some existing customers would scream about the $150 price for a firmware upgrade. Most other civilian GPS receivers have a maximum speed limit of very approximately 1000 knots and a maximum altitude (of ~65000? ft) to discourage their use on intercontinental ballistic missiles. | 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! It is possible that it was different in previous (or later) versions of firmware but I doubt it. If you have any evidence to the contrary, I am interested! This limitation has created a lot of debate in the GPS newsgroup primarily because it is not well documented and is arbitrary. Recent reports indicate that it is now mentioned very briefly deep inside newer versions of the 40 manual. Obviously every potential customer does not take an hour to read the manual before deciding to purchase the unit. I feel that people should should be warned about the limitation since it is not expected since most (all?) other manufacturers' units work up to approximately 1000 knots. | 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 manufacturer's 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 45/40 firmware versions: The firmware is believed to be identical between the 2 products except for the strings "45" and "40" (which could still be the same EPROM). V2.02 4/94 Early release of GPS 45 ... V2.20 ... 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 Some units have simulator random power down problem (minor)++ V2.42 7/95 Fixed simulator random power down problem V2.43 9/95 New version. | The above dates are approximate within about 1 month. If you want to update your firmware, you can 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 what is required for the EPROM replacement. ++Simulator mode is a mode which simulates satellite signal acquisition, presumably when you are not outside and want to practice with the unit. You can still program the unit indoors without it, however in normal mode the unit will automatically shut down after 15 minutes of not locking on the satellites to conserve the batteries. I have seen the simulator bug in V2.41 of the software. Recent reports indicate that it does not affect all units with V2.41 firmware. If a unit has the bug, when you are in simulator mode after an apparently random amount of time (usually between about 5 seconds and 15 minutes), the unit turns itself off. You simply turn it back on or use normal mode and turn it back on every 15 minutes. This is not a serious problem. 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 and displays labeled SNR Signal to Noise ratio? DRIFT of FREQ below FREQ apparently this is a 16 MHz internal clock TEMP degrees Celsius BATTERY voltage in hundredths of Volts EXTERNAL unknown | TIME universal coordinated time without local offset | Press LEFT or RIGHT arrows to adjust contrast. Press ENTER 2 times to get an all black screen, press ENTER again for cool exploding rectangles on the display. Press ENTER again to exit this mode. Hold down OFF button to exit test screen. 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!!!). DO NOT TRY THIS UNLESS YOU ARE WILLING TO LOSE ALL SAVED INFO!!!!!!!!!! Waypoints, Track, Routes and more will all be gone. I would not 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)! It returns all settings to initial factory defaults. Diag mode: | Quickly after turning on the power (while the globe is still spinning), press all 4 arrows one at a time (in any order) to get into this mode. 2 or 3 digit numbers are added to many screens. Their meaning is unknown at this time. The signal strength bars are initially hollow. This could relate to whether some specific data has been downloaded from the satellite yet. It has been suggested that the number in the bottom right of the satellite screen could be the Geometric Dilution Of Precision (GDOP). The internal temperature in degrees Fahrenheit is added to the position screen. A "DIAG" option is added at the bottom of the menu screen. The following is displayed on the DIAG screen: Battery voltage in hundredths of volts. Elapsed time since power on (can be cleared by pressing ENTER). Screen can be paused by pressing MARK. Looks like a lot of internal software debugging info is included. -Why is internal temperature available? | In some electronic designs, it is useful to measure the internal temperature of certain components so that the information can be used to compensate for changes in the components over temperature. As the unit warms up, this temperature will generally be warmer than the ambient (surrounding) temperature. The internal temperature is not intended for use as a thermometer to measure the air temperature! There are two different modes on the GPS 45/40 that allow you to read the internal temperature. One is in Celsius, the other is in Fahrenheit. See above for details. I would speculate that the temperature is used to monitor the drift of the 16 MHz clock since apparently the frequency drift info is displayed in one of the screens above. 4.00 BATTERY/POWER QUESTIONS: ------------------------ -How is power selected between the internal batteries and the external supply? This differs between the 40 and the 45. The 45 switches completely to the supply with the highest voltage. The 40 does a slower crossover from one supply to the other as the voltage of one exceeds the voltage of the other, and will draw part of its operating current from a current-limited external supply such as a solar panel, even if the current-limited supply cannot supply the total power needs of the GPS 40. The remaining current which the solar panel cannot supply is supplied by the internal batteries. | lwjames@ix.netcom.com 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. DC supplied thru battery compartment [V2.32] 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 hysteresis, hence the tilde. Unit transitioned smoothly between external dc and internal batteries when external power was cycled (unit did not lose sat lock). davew@cruzio.com (David Wells) You can easily calibrate your own unit by going into the test screen or diag mode as explained under the FIRMWARE section and just compare the battery voltage with the fuel gauge. -Current draw of a GPS 45 at different external supply input voltages? This is from a GPS 45 unit with V2.41 firmware and internal batteries removed: (There are manufacturing variations between units and this does NOT apply to a GPS 40) POWER POWER V in OFF ON ---- --- -- 6.25 V 1.0 mA unit turned itself off 7 V 1.1 mA 144-166 mA 8 V 1.3 mA 120-138 mA 10 V 1.8 mA 80-100 mA GPS 45 only, GPS 40 might be damaged! 12 V 2.3 mA 68-84 mA GPS 45 only, GPS 40 might be damaged! 14 V 2.8 mA 62-78 mA GPS 45 only, GPS 40 might be damaged! 16 V 3.3 mA 62-76 mA GPS 45 only, GPS 40 might be damaged! 24 V 5.2 mA 64-80 mA GPS 45 only, GPS 40 might be damaged! 32 V 7.1 mA 64-80 mA GPS 45 only, GPS 40 might be damaged! >From this data, I conclude that you do not want your GPS 45 external supply to drop down below about 7 Volts. Also, there is no advantage to a supply with more than about 14 Volts as the extra voltage will just be converted to heat. -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. If you have a strong signal, it probably does not hurt to leave it in battery saver mode. If you have a weak signal it could cause you to lose all of your satellites (I have experienced this) and will never reacquire them as indicated by the Garmin support department. If you change modes, then the unit loses all satellites and must reacquire them (although it happens quickly). There have been suggestions that the BatterySave mode works best when you are stationary or on a straight steady route. It probably does worst when carried by a hiker through the trees because of the erratic movement and the marginal signal conditions. -Battery Options? Nickel Cadmium batteries are much cheaper than alkaline batteries 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 alkaline. Also, the fuel gauge gives a less accurate state of charge for NiCd batteries because they have a more constant voltage over their discharge cycle instead of the gradually decreasing voltage of alkaline. The fuel gauge is still useful, it is just harder to predict your remaining battery life. You could also use Rayovac Renewal (tm) batteries which are rechargeable alkaline batteries. They are only rated for about 25 recharges (compared with approximately 1000 recharges for NiCd batteries) but should 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. Do not forget the 1/4 A fuse for the power in. Some people have also hooked an optional power cord to an external battery pack that could supply power for days of use. Select your battery pack voltage carefully! Usually, you do not want most batteries to be discharged below 0.9 V /cell. See a previous section for info on current consumption at different voltages (for the GPS 45 only). Again, do not forget the 1/4 A fuse for the power in. | For a GPS 40 (which has an input voltage of 5-8 V), 5 D-cell alkaline batteries would work out well (5 x 1.5V = 7.5V). For a GPS 40 with NiCd's, 5 or 6 cells should work. (6 cells would be too high a voltage with other types of batteries). | -How long is the memory conserved without batteries? Tim Hogard reported at least a week. There have not been a lot of reports of erased memory when changing batteries so it must not be too much of a problem. -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 negligible. tmiller@umabnet.ab.umd.edu (Tom Miller) I tested the GPS 40 and it too does the same. davew@cruzio.com 5.00 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). If anybody finds an alternate source for the correct connector, please let me know. 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 personally feel that building your own cable is 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 between the pin and socket size if you do not replace the sockets (been there, done that!). Some people have substituted a 5 or 8 socket DIN connector for the GPS 40 or a 4 or 7 socket DIN connector for the GPS 45. There are several socket arrangements for the DIN connectors (even with the same number of sockets!). You should plug any unused holes and if you are using the DIN sockets (not as reliable), you should bend the contacts 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/or heat shrink tubing to bring it out to the correct diameter. If you do not do a good job on this last step, you risk damaging your unit due to mis-indexing the connector. Here is a much better design (using Radio Shack parts) for a home built cable by Rane Curl: The connector for the Garmin GPS 45/40 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. They are serial 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. See the next section for the pin out. -How do I interface the GPS 45/40 to an IBM-PC compatible computer? Garmin DB-25 DE-9 Function color* socket socket -------- ------ ----- ---- 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, do not forget to add a 1/4 Amp fuse!) *Garmin 45 manual, Appendix F I strongly recommend using Garmin's wire colors as stated in the manual to minimize confusion. If you don't have your manual handy, you can use the following info. Cable view: slot clockwise power (red), data out (brown), ground (black) and data in (white). So the back of the unit is male and the opposite would be true. That is, from the slot clockwise: data in, ground, data out, and power. [original contributor unknown] 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 a 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. The NMEA 183 hardware standard is NOT RS-232 but will usually work when connected to RS-232 devices such as a serial port on a PC. Apparently the NMEA 183 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. Supposedly the (0 to 5 V) GPS 45 and 40 have protection for the IBM-PC compatible +12 and -12 V RS-232 levels. You can directly connect (using only 3 wires and no handshaking on the PC) the GPS 45/40 to a PC. It does work well for almost everybody but Garmin will not guarantee it in case there are problems in peculiar circumstances. The handshaking lines for the PC should not be required for Garmin or NMEA 183 specific software. Some terminal programs could require handshaking lines tied back on the PC side. -How do I interface the GPS 45/40 to a Macintosh? (files are available in FAQ section "GPS 45/40 ftp/www sites") 1) In the MacGPS-45 program documentation, there is a good cable design for use between the Macintosh and GPS 45/40. 2) There is a good universal NMEA/RS-232 interface design for all types of computers. You can download the following file from Peter's ftp site. 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? Tom Miller and Tim Hogard bravely took apart their GPS 45/40 and they described the circuit board. Check out Tim Hogard's home page: http://inmind.com/~thogard Here are some of the most interesting identified parts: Manuf. Part No # pins Function INTEL TS80L188EB13 80 CMOS 80188 cpu ATMEL AT27LV020 32 3.3V 256k x 8 (2Mbit) EPROM DALLAS DS1202 8 serial time IC & small NVRAM MITS M5M5256CVP 28 32K x 8 SRAM PHILIPS SA626DK 20 FM IF amp,det,limtr,mixer,osc The Intel 80188 microcontroller is a derivative of the Intel 8088 microprocessor used in the original IBM-PC. | Contrary to some initial reports, the firmware is not in flash memory. (Flash memory would be of interest because flash is re-programmable without removing the part from the board). The EPROM (which contains the firmware) is a "One Time Programmable" (really an EPROM without a window) surface mount unsocketed part. The fact that the firmware is 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. 6.00 APPLICATION SOFTWARE: --------------------- | -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 mostly 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 am not sure of the exact wiring of their cable. Is anyone willing to check it out with an ohmmeter? Fortunately several people have generously written several other much less expensive programs for our benefit: MacGPS-45 (Macintosh freeware) Originally written by John Waers and now being enhanced by Larry James. A Mac specific program for the GPS 45/40. It includes real-time display and logging of NMEA 183 data and upload/download of Garmin data. The complete Macintosh version is available from the "ftp/www sites" section. **** PC-Users: The sources for MacGPS-45 also contain the Garmin proprietary transfer format. An incomplete version for NON-Macintosh users is available on Peter's ftp/www site described later. GARDOWN by M.J. Montgomery (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 (shareware, $20): 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. 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. Do not forget you may have to set your GPS 45/40 "I/O SETUP" to "GRMN/GRMN HOST" or the above programs may not 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 (freeware): A Windows program written in Visual BASIC that talks NMEA 0183 but has some Garmin options. It works with the Garmin data files used by the utility GARMIN by Peter Aigner. JNAV82.ZIP by Joel C. Koch (shareware $50): A DOS program that displays and logs NMEA 0183 data. GPSNMEA by Dr.W.Pieper (): A DOS program that displays and logs NMEA 0183 data. GARMIN65.NMEA Prepared by Peter Bennett (bennett@triumf.ca) An annotated listing of NMEA sentences (including Garmin unique sentences) sent by a Garmin GPS 65. The GPS 45/40 is very similar. 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. [Garmin mode] "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 [NMEA 183] "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 [NMEA 183] "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 most of the freeware/shareware programs above: ftp to "sundae.triumf.ca", cd to /pub/peter or web address "ftp://sundae.triumf.ca/pub/peter" Larry James has inherited the MacGPS_45 software: ftp://ftp.hawaii.edu/mirrors/info-mac/sci/larrys-mac-gps.hqx Tim Hogard has some internal electrical hardware information on his Web site: http://inmind.com/~thogard Albert Nurick has started up a new site: http://www.tech.net/technotes/gps/ Good general GPS info: http://wwwhost.cc.utexas.edu/ftp/pub/grg/gcraft/notes/gps/gps.html | US Coast Guard: http://www.navcen.uscg.mil/ | I will continue adding to this list. 7.00 ANTENNA QUESTIONS: ------------------ -What is the GPS 40 internal antenna? It is called "patch antenna". The same antenna is also used on the optional remote antennas GA 27 (GPS 40) and GA 26 (GPS 45) except that it is amplified on the remote antennas. | -How is the GPS 45 antenna internally constructed? Thanks to a friend (Mike Petterson) whose GPS 45 antenna case split open, 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 about a 1/2 inch diameter cylinder. It has 4 spiral elements that look like the stripes on a candy cane. It is definitely a passive (non-amplified) antenna which works pretty well. Someone has X-rayed their GPS 45 antenna and scanned the image. Look at the files grm45ant.gif and grm45ant.inf on Peter's ftp/www site as listed elsewhere in the FAQ. | -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 or trees. The more the windshield is angled back, the better you will do. There are some window tintings (which could also apply to a sunroof) and some (European) electric window defoggers that use a conductive coating between the layers of glass that block the satellite signals. These are unusual but they will shield the signals from the antenna. 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) 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. 2) 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. The satellite signals are severely attenuated by coaxial cable at the GPS (civilian) frequency of about 1.5 GHz. If the original (non-amplified) antenna is used, the length should be kept less than several meters. Garmin sells a couple of external antennas that work very well. There is a wide range of mounting options including suction cups, magnetic, flange, and trunk lid mounts. See the accessories section of the FAQ for details. Many people have reported that the external antennas work better than the built in antennas even when they are walking. This could be because your body is not shielding the signal and most external antennas are amplified. You could mount the external antenna on a hat or a pipe coming out of a backpack. GPS 45: You can buy a SHORT coax extension and mount the antenna on the inside of your windshield or sunroof. Radio Shack sells two 6 foot coax RG-58/U extensions with suction cup mounts (RS 20-022) or a window edge mount (RS 20-023) for about $15. You will need a 90 degree elbow for the window mount and it is useful for the suction cup mount too. The window edge mount works great for me. You can also just buy the coax alone for less but you will need a BNC gender changer and a way to mount it. I did some tests earlier with several used short pieces of coax and did not have good results. After seeing some contrary postings, I retested with new coax and had much better results. Apparently my used coax was defective. | The 6 ft of RG-58/U (a very lossy coax at these frequencies) drops the signal strength a little on the display. I saw a lot of attenuation with old pieces of cable but I assume that it was abused because I have not seen problems with new cable. I also have not yet taken the time to calibrate the signal strength indicator in dBs. If anybody has, I would be interested in seeing the information. -Can I make my own external antenna? Yes. There have been several postings and articles that reference the articles below: In the ham radio magazine "QST" (October 1995) there is a good article on how to simply construct a "patch" style GPS antenna using easy to obtain materials. | Look at the "Satellite Experimenter's Handbook" (by Martin R. Davidoff, published by the American Radio Relay League) for their quadrifilar helix antenna. It could be tough for some people to get the very small coaxial hardline that is needed and the dimensions are critical. 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, good gain at 1.5 GHz, and its easy in matching. It also only costs about $2. I read somewhere that Ma/Com also makes a GPS preamplifier IC ($8) which is designed for this application (but much harder to obtain). I recall reading somewhere that Ma/Com sells a non-amplified remote GPS antenna for about $50. Does anyone know where that is available? | 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 at 1.5 GHz and flexibility but it is not 50 ohms. Another poster independently came to the same conclusion. This would not be much of an issue if the run was less than several meters. 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. 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 8.00 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 are very inexpensive. -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. The battery compartment is not waterproof. 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. If you don't want to take any chances, buy a marine radio waterproof plastic bag. They usually have a huge Zip-Lock (tm) seal which keeps the water out very effectively. | Someone else suggested that you should grease the GPS 45 antenna connector before exposing it to salt water to help prevent corrosion. -Cases? 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 have not 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 "West Marine" printed on it for $10. It is NOT waterproof. 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. It is a good investment in my opinion. I have heard reports that they are hard to locate but I have seen them in some stores recently. The model is "F-2Y" #253791. -Garmin 45/40 wish list? Remove the 90 knot speed limit. Add a display mode in which the velocity and heading in degrees are in HUGE numbers for easier viewing from a distance. Add distance traveled function (not straight line distance between 2 points). Perhaps select end points by waypoints or on track log. This data is already in the track log. This would be subject to SA errors of course so perhaps it could have some sort of crude averaging. Add stationary position averaging feature for more accuracy. Add selectable longer velocity averaging time? Currently about 5 seconds? It is currently of little value for velocity on sailboats. Remove the limitation of only showing the 9 closest waypoints on the track log map. This is very annoying! Adjustable proximity alarms. -Can I use my GPS unit 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). It is against most airline policies to allow use of most electronic devices during takeoff and landing (and some extend beyond that). I have not seen the specific FAA rules so am not sure if they have additional limitations. | 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 for all GPS receivers. The attenuation depends on the density of the canopy, and how much moisture is in and on the leaves. If the canopy is too dense (pretty common in the forest), you may have to find a clearing to get a fix. Several people have reported that the Garmin external antennas attached to the top of a backpack or hat work better than using the built-in antenna. 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 5-8 continuous channels like some other units. Continuous receivers are able to track more marginal signals at once. However, they cost more, are larger, and do not have the battery life of a sequencing receiver such as the GPS 45/40. Is the GPS 45/40 a 1 or 2 continuous channel, 8 sequencing channel receiver? I know it is a sequencing receiver. I do not see it documented anywhere. 9.00 GARMIN AVAILABILITY: -Other Garmin GPS models < $1000 US? Here is a quick table I created based on posts that I recall reading. It probably is not absolutely accurate! I am not sure what the true upper speed limit is either. If somebody can accurately supply the missing info, let me know. INTRO US US MODEL USE YEAR SPEED LIMIT $LIST DISC$ ----- --- ---- ----------- ----- ----- GPS 40 marine, hiking 1994 90 knots $499 $300 GPS 45 marine, hiking 1994 90 knots $499 $300 GPS 50 marine, old, replaced by GPS 75 ? 90 knots? NA NA GPS 55 aviation 1992 ~999 knots? GPS 65 marine, requires ext. power 1992 90 knots? GPS 75 marine 1992? 90 knots? GPS 90 aviation, similar to GPS 45 1995 999 knots $799 GPS 95XL aviation ? ~999 knots? $1495 Notice that all of Garmin's marine units apparently have an artificially low speed limit. This speed limit did not start with the Garmin 45/40 as some have suggested. -Garmin accessories? Here is a list of most Garmin accessories. List prices as of Feb 1995: GPS40 part number Item description list price GA27 Low Profile remote ant w/8ft [RG-174] $ 160.00 cable 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 GPS 40/45 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) -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 most 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 303-530-9014 E-mail: lwjames@ix.netcom.com (Larry is very knowledgeable about Garmin units and often answers questions in the GPS newsgroup. He also has particularly good prices on options such as antennas.) ---------------------------------------------------------------------- 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 A. Holdcroft klah@eskimo.com KE7UT