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Appeared on: Friday, February 09, 2007
F-Tech Solar MT

1. Introduction

F-Tech was first to present a solar powered GPS receiver based on the SiRF StarIII chipset. The technology has developed further and now, F-Tech has introduced a new series of solar powered GPS receivers, smaller in dimensions and using a different chipset from MediaTek. The F-Tech Solar 2.5MR promises superb technology and autonomy. We compare it with a well known SiRF Star III receiver from Globalsat, the BT-338.

- F-Tech Solar 2.5MR

Mini Solar Bluetooth GPS Receiver is a total solution for GPS receivers. High capacity rechargeable lithium-ion battery, GPS antenna, Blue tooth transmit/receive system are included. It is designed on the most advanced chipset solutions, using either the SiRF starIII or MediaTek, providing full-functionality, RoHS compliance, industry-level locating capacity and low prices.

You can use the Mini Solar Bluetooth GPS Receiver as a vehicle navigator, security system, geographic measurement tool, and for agriculture purposes. The Mini Solar Bluetooth GPS Receiver operation requirement is a proper power supply and the open sky-view. This Bluetooth GPS Receiver can communicate with other electronic devices through the Blue-tooth interface. Built-In Flash Memory can save satellite information and do almanac refresh periodically. This will shorten Time To First Fix (TTFF) effectively.

The battery life is much longer than that offered by competitor devices. The Lithium-ion battery can be re-charged under natural or artificial light, regardless of whether the BT2.5 receiver is turned on or off. Most of the time, you will not require a charger! The Mini Solar Bluetooth GPS Receiver is designed for high position accuracy. It will update the satellite position every second. The Mini Solar Bluetooth GPS Receiver auto-locating feature, is capable of automatically determining a navigation solution without intervention.

- Features and Functions

  1. Total solution in power management. Unique Solar Cell re-charging design (patent protected)
  2. Green solution in wireless GPS receiver application. Always charge your lithium-ion battery under natural or artificial light. Spare your charger, Spare your space
  3. Considerate LED/switch button design. Easy look, easy touch !one-touch button design keeps your hands free
  4. Act as WARM/HOT start with built-in battery. Effectively shortens TTFF.
  5. Automatic almanac/ephemeris update in flash memory. Programmable flash utility to do refresh on satellite orbit data information every 10 minutes
  6. Smart power management solution. GPS Device will automatically shutdown in cases where Bluetooth is not detected after a default period of time
  7. Compatible with Bluetooth Serial Port Profile (SPP)
  8. Easy application for vehicle, trip navigation, vehicle management, AVL, personal navigation, tracking system and map applications.

- Used chipset

The new solution from F-Tech uses the MediaTek MT3 GPS chipset. Below we can see a comparison between the MT3 and SiRF Star III chipsets:

Core GPS processor
MediaTek MT3
Working Frequency
L1, 1575.42MHz
C/A code
1.023 MHz chip rate
Satellite Tracking Count
32 (NEW)
Antenna Type
Acquiring Position Speed
Cold Start
<37 Sec, average
<41 Sec, average
Warm Start
<36 Sec, average
<37 Sec, average
Hot Start
<1 Sec, average
<1 Sec, average
Reacquisition Time
<1 Sec
0.1 Sec (Typical)
Refresh Rate
Up to 5 Hz
1 Hz
Acquiring Position Accuracy
3m CEP(50%),
without SA (horizontal)
10 meters, 2D RMS
7 meters, 2D RMS
0.1 m/sec
100 ns RMS
1 microsecond
synchronized to GPS time
Acquiring Position Range
GPS Protocol
Baud Rate
Input Power
Power consumption
45 mA average
75 mA average
30 mA with Solar panel
60 mA with Solar panel
Working Environment
Working Temp.
-40°C ~ +85°C
Relative Humidity
5% ~ 95% un-compressed

Looking at the specs, we can see significant differences between the chipsets in terms of sensitivity, cold start time and refresh rate. Both receivers support WAAS/EGNOS, although the MT3 promises much better "position accuracy" (2.5 vs 7.0m) compared with the SiRFStarIII. Another interesting feature is the much lower power consumption, 45mA vs 75mA, and with the Solar panel, the MT3 chipset can stay online for twice as long as the SiRFStarIII.

2. Package

For our testing purposes, F-Tech sent us the retail package which includes:

The current price for the product is around US$99.99, as found around the net.

The F-Tech Solar 2.5MR GPS receiver is slightly bigger than the BT-338, an improvement over the previous generation:.

On the top are the power on/off switch, three LEDs and the charger input. On the left side is the external cable jack (MMCX compatible).

Looking on the underside, we find information about the product, like S/N and the exact model identification.

There three LEDs have the following behaviour:

The battery is a 1000mAh 3.7V

3. Installation

Installing the device is very easy. After charging for a little over 2 hours, you can install it either on your PDA or BT enabled laptop. Remember, that the pairing key is four zeros (0000), in case the application asks for it. We recorded all data for a pre-selected route with VisualGPSX and later analyzed it with GPSLog.

Unfortunately, there is no way to measure the TTFF times ("Time to First Fix" which is the time it takes for a GPS to determine its current position), since there isn't any software that could be used to perform a "Cold Start" function. All tests ran simultaneously, under the same environmental conditions.

- Outdoor Tests

We tested the devices in daytime with a partly cloudy sky. Temperature was 15°C.

Globalsat BT-338
F-Tech Solar 2.5MR
Time to First Fix (TTFF)
39 sec
? sec


Average (in view)
Average (in use)
Average Signal Level (in dB)
Maximum per Satellite
Average per Satellite

The analysis results for both GPS receivers showed that Globalsat BT-338 still holds its own in the GPS market, since it didn't at any time lose its 3D Fix and had higher Signal levels per satellite. The F-Tech Solar 2.5MR on the other had, momentarily lost its 3D fix (99.8%) and had much higher number of satellites in view, but lower in use. Its signal levels were somewhat lower than the BT-338. Most users won't even notice the differences...

- Indoor Sensitivity

We placed both receivers inside a house close to a big window and monitored their performance. Both receivers had a 3D fix all the time and almost similar performance. We noticed that the BT-338 had better sensitivity reporting satellites with less than 20dB signal level.

4. Conclusion

- Conclusion

F-Tech's Solar 2.5MR GPS device is unique, combining the strengths of the MediaTek MT3 GPS chipset with a built-in solar charger. According to F-Tech's website, there's also a SiRF III version available (which we didn't test). The MediaTek version, powered by the solar panel, should operate for up to twice as long as the SiRF III version, since it consumes about half the power. We are not very sure how long the MediaTek version can operate for, since the solar panel offers extra operating time, and is especially effective in full sunlight.

Looking at performance and in comparison to the SiRF Star III based Globalsat BT-338, the Globalsat BT-338 was found to have higher reception signal levels but lower number of satellites. The MediaTek MT3 chipset appears to be powerful enough to compete with the SiRF Star III chipsets, but the unfortunately there's no software that could be used to further tune the GPS device's performance. The addition of an external antenna will further improve reception levels. The price for the F-Tech Solar 2.5MR is around US$80-90.00 making it a very affordable and attractive solution for end users.

The Positive

The Negative

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