Garmin's GTM-10 Data Receiver
Review by Joe Mehaffey
Release 2, November 19, 2005
What is the GTM-10?

The GTM-10 RDS radio receiver is a new offering by Garmin for use with the NuVi 350, StreetPilot c340, StreetPilot 2720, StreetPilot 7200, and StreetPilot 7500.  This radio receiver listens on the commercial FM radio band and receives for Traffic Message Channel (TMC) data.  This data is received, converted to USB compatible data and forwarded to compatible GPS receivers.  The technology used is normally known as RDS or Radio Data Service and has been in use in Europe for many years.  I have a bit of experience in the UK with early versions of this service.   European (and especially in the UK) service has much better coverage and information available than do the three market areas I have visited with the GTM-10 in the USA.  More on this later.  Street prices for this Garmin GPS accessory are in the $200 and less range.  CLICK HERE for latest prices.

What is the system designed to accomplish?
For some years, local governments in cooperation with various FM radio stations have been putting together an automated way to get real-time traffic data into your car so you can use it to help avoid traffic.  Real time traffic information includes such news as: Congestion, construction,  traffic accident, recommended alternative routes.  As of Winter 2005, data streams were available from multiple FM stations in the following areas under the Clear Channel service name.
Atlanta, GA Austin, TX Baltimore, MD
Boston, MA Charlotte-Gastonia-Rock H,NC-SC Chicago, IL
Cincinnati, OH Cleveland, OH Columbus, OH
Dallas-Ft. Worth, TX Denver-Boulder, CO Detroit, MI
Greensboro-Winston Salem, NC Hartford-New Britain, CT Houston-Galveston, TX
Indianapolis, IN Jacksonville, FL Kansas City, KS-MO
Las Vegas, NV Los Angeles, CA Memphis, TN
Miami-Ft. Lauderdale,FL Middlesex-Somerset-Union, NJ Milwaukee-Racine, WI
Minneapolis-St. Paul,MN Nashville, TN Nassau-Suffolk, NY
New Orleans, LA New York, NY Norfolk-Virginia Beach, VA
Orlando, FL Philadelphia, PA Phoenix, AZ
Pittsburgh, PA Portland, OR Providence-Warwick-Pawtucket,RI
Raleigh-Durham, NC Riverside-San Bernardino, CA Sacramento, CA
Salt Lake City-Ogden-Provo, UT San Antonio, TX San Diego, CA
San Francisco, CA San Jose, CA Seattle-Tacoma, WA
St. Louis, MO Tampa-St. Petersburg,FL Washington, DC

The "service" is provided under the umbrella company CLEAR CHANNEL.  The GTM-10 comes with a 15 month subscription to the service and after that, a renewal will cost $60 per year in the USA.  For information about the service and costs in the UK and Europe, check the GTM-10 page on the Garmin website.

Does the system require installation?
Yes, at least some  installation.  Joe has been riding around with a magnetic mount  with a 29 inch (FM band) whip on the car and with this antenna connected to the GTM-10 and then the GTM-10 connected to the GPS.  All this works fine.  More recently,  I have installed this tiny receiver behind the radio in my car.  Installation is simple and involves: 1) slide the radio from its slot in the car so you can reach the ANTENNA cable.  2) Unplug the existing antenna.  3) Using one of the furnished adapter cables,  connect the OUTPUT of the GTM-10 to the antenna input on the radio.  4) Using another adapter cable from the kit,  connect the existing antenna cable to the GTM-10.  5) Find a route for the GTM-10 USB cable to exit the space behind the radio and  lead it to the location of your GPS by whatever route is most convenient and neat for your particular car.  6)  Plug the USB cable into your compatible GPS and the install is complete except for enabling the feature in the GPS unit's software.

Can I play the regular FM or AM radio while using the GTM-10?
Yes, the GTM-10 does not interfere with normal entertainment radio operation.  It simply shares the antenna with the entertainment radio.

Is this information more timely or more reliable than traffic information available over my car radio?
In the UK, I would say yes.. My experience in (only) three markets in the USA is less positive.  I have toured extensively around Atlanta and Memphis for days at a time during the rush hour with the GTM-10 and SP2720.  I can tell you that the EQUIPMENT performed flawlessly and as expected.  The DATA available via the service was less than stellar in quality.  In both Atlanta and Memphis I encountered accidents and traffic stoppages on freeways that did not show up on the Clear Channel service.  In Memphis, I heard a couple of advisories suggesting alternative routes to avoid traffic.  On the two occasions I took the alternative, it was worse (I think) than the primary route turned out to be.  As a result, I feel that (in Atlanta and Memphis) the DATA needs a whole lot of work before it will really be all that useful as a motorists tool.  On the other hand, the equipment appears to work fine and we have to realize that, in the USA, this service is relatively new.  Growing pains have to be expected for a few years at least. NOTE:  Please EMAIL JOE with your comments about GTM-10 operation in other cities.  I would like to report how this system works in other cities to our readers.

Does the map actually show you roads under construction, traffic tie ups and such?
Yes, it works just as advertised.  And usually when you got to where the traffic tie ups were shown, things did get a bit worse than usual as far as traffic is concerned.  So far, I have not had the system offer an alternative route in Atlanta, but in Memphis, I did see some few suggested alternative routes.  I also explored Nashville with the system, but it was not during the rush hour and not much was going on for it to report. 

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