Qstarz BT-Q818Looks good and SOUNDS good…

Our quest for ever smaller GPS receivers has taken us today to the Qstarz BT-Q920 with a really tiny footprint. However, the Qstarz BT-Q920 GPS Receiver also comes with an interesting addition which brings back its proportions to a normal size.

I’m talking about the FM transmitter which allows you to play music through your car stereo system. Is this a case of useful integration or does it fall in the category BWC — Because We Can?

Let’s take the show on the road.

And by the way, the first pictures were shown on our sister site PocketPCReviews.net, where we first announced this little gem to the world. 

Qstarz BT-Q818Those who haven’t read our previous review of the Qstarz BT-Q818 may not know that Qstarz has been bringing out some innovative GPS receivers of late, including the “Double 32”.

These are all excellent performers with high sensitivity and great endurance.  That means that our expectations for this tiny receiver, are set very high.  Perhaps unreasonably high considering its small size.

Well, as far as sensitivity is concerned the 20 channel GPS receiver is based on the renowned SIRF Star III chipset which guarantees excellent performance even in marginal conditions such as urban canyons.  In our testing the nearest high-rise cityscapes are 450 kilometres away but we did test the Qstarz BT-Q920 GPS Receiver under high tree canopies and away from windows.

The super high sensitivity of -159dBm allows you to get away from windows for several metres before the signal is lost.

What’s In The Box?
The standard package for the Qstarz BT-Q920 GPS Receiver includes a lithium ion rechargeable battery plus cigarette adaptor and travel charger (which should have the correct plug for your country).  You also get a lanyard and a Quick Installation Guide.
I quite like the silver grey casing and blue top appearance of this model which has the power button on the lower left with three LEDs of a decreasing size.
The left, and larger one, is the green Led for GPS status.  The blue middle one indicates the bluetooth status one is indicating your battery.
It seems that in all my reviews I have something to say about blinking LEDs.  In my opinion LEDs should not blink when a connection has been established.  Blinking LEDs only attract unwarranted attention to themselves which can be very annoying.
Qstarz got it half right with the green GPS LED being solid and the bluetooth LED still blinking away…
On the bottom of the unit is an anti slip strip, giving it a solid grip on the dashboard.
This unit has a red cloth tag with the bluetooth signal which doesn’t do anything to enhance the product and should be left off.  I have seen similar labels on other products and if it is a fashion statement we will soon grow out of it…

FM Transmitter
There is a mini USB Port for the optional FM transmitter which attaches here.  That makes the Qstarz BT-Q920 GPS Receiver about 60% bigger but adds an interesting functionality.
The key word here is ” interesting”…
I’ve had some bad experiences with devices like FM transmitters which are very susceptible to interference.  The idea is to select an FM frequency that works with the least amount of interference so that you can listen to music from you iPod or MP3 player through your car speakers.  I tried it first with my home stereo systems and on different frequencies.  The results were not encouraging and I could not find a frequency that would transmit without interference.
The car stereo proved a better platform and I easily found several frequencies that would work properly.  So this $15.00 option can be very handy indeed to play MP3 songs from your PDA or iPod and transform them into glorious car stereo sounds.

Qstarz BT-Q818 FM attachmentBattery Life
The power jack is a small 2.35 MM and a couple of hours on the wall charger should give you about 12 hours in return.
In my book that’s quite a decent stretch of time, considering that the first bluetooth GPS receiver we reviewed, the venerable Emtac, only managed about 4 hours.  If you’re on the road the travel charger should give you continuous power and will keep your unit topped up.
The reality check on the battery endurance showed us a decent 10 hours which is close enough.  I figure that if a device obtains at least 80 per cent of the claimed values, which are always obtained in the most ideal test situations, then we’re doing pretty good.
One of the excellent features that helps to stretch the battery life is that the unit will switch off when a bluetooth connection drops out.
The battery, by the way, is replaceable by disconnecting the battery connector.  Not quite as easy as some of the slide-in replaceable batteries but then again, I have never ever had to replace any GPS batteries.

Other Standard Testing
Our usual testing pattern includes several hours of driving and a test flight in my aircraft.  Accuracy is very good, which is not surprising considering the fact that the SIRF Star III is its heart. Quick startup and acquisition times (see Specifications) also make the BT-Q920 an ideal travelling companion.

It is inevitable that GPS receivers will get smaller and smaller.  The Qstarz BT-Q920 is certainly on the forefront of this trend.  Generally, a smaller footprint is the way to go but also makes it easier to lose the unit.  For me, I appreciate the tiny form factor because the endurance has not been sacrificed.  Auto-ShutOff when a bluetooth connection drops out is a great battery saver. Value for money at the price of Euro89 is good.  We can certainly recommend the Qstarz BT-Q920 GPS Receiver highly as there are no discernible negative points.  In fact, the optional FM transmitter just tipped it over to the point where we can award our highest accolade to this nifty little device: the DigitalReviews Editor’s Choice!


GPS Chip
L1, 1575.42MHz
C/A Code
1.023MHz chip rate
Support 20 channels
Antenna (Intemal)
Built-in low noise antenna
To -159dBm Tracking, Superior Urban Canyon Performance
Acquisition Rate
Cold Start
42 sec, average
Warm Start
38 sec, average
Hot Start
1 sec, average
up to 10 M at 2D RMS
0.1m /sec, without SA
1 m s synchronized to GPS time
Built-in rechargeable Li-ion battery and input
Operation Current
up to 75mA (Typical)
Operation Time
12hrs, fully charged, in continuous mode
Charging time
4.0hrs. (Typical)
Input Voltage
5.5 0.5 V DC
Dynamic Conditions
up to18,000m
up to 515m /sec
up to 4G
Motional Jerk
4 m /sec.
Communication Protocol
Communicate with host platform via
Bluetooth (class 2) serial port profile
Bluetooth communication distance 10 M .(Typical).
GPS Protocol
Default: NMEA-0183 – GGA, GSA, GSV, GLL, RMC,VTG Baud rate 4800~38400 bps, Data bit : 8, stop bit : 1(Default) *
Device Size
59 (W) x 44 (D) x 21 (H) ( m m)
60g (including battery)
Car charger (mini USB) AC adaptor (Optional)
Rechargeable Battery
Operating Temperature – 10°C to + 60°C
Storage Temperature
– 20°C to + 85°C