After more than a year of rigorous internal testing we’re happy to announce start of public sales of UmTRX 2.3.1 – the only widely available Software Defined Radio (SDR) designed specifically for telecom applications.
Our goal from the beginning – when we made the first UmTRX design in 2011 – was to create an SDR which meets all rigid technical and legal requirements for telecommunication equipment. And make sure it has a reasonable cost, so e.g. you don’t have to spend extra $600-$900 for a GPS Disciplined Oscillator (GPSDO) after you already spend $700-$800 on an SDR – hence all UmTRX come with a built-in GPS. Our original focus was on 2G/GSM, but with up to 30.72 MSPS UmTRX 2.3.1 handles 3G/UMTS and 4G/LTE just as well.
It took us 5 hardware revisions to get to UmTRX 2.2 which was the first UmTRX we were happy with. We’ve built UmDESK desktop BTS based on UmTRX 2.2 and it found many users since it was introduced in 2013.
With the experience we obtained building the UmDESK, we set the bar higher – to create a lightweight and inexpensive outdoor base station.
This led us to start on a new UmTRX design with a goal to make it more compact and suitable for embedded environment; the UmTRX 2.3.1 was born!
It’s now used in all our outdoor UmSITE base stations which are deployed on all continents except Antarctica and are suitable for both Siberia-cold and Sahara-hot temperatures (see UmSITE temperature tests).
Why UmTRX 2.3.1?
UmTRX 2.3.1 is a compact dual-channel SDR built for embedded systems suitable for industrial, outdoor, harsh and remote environments. It is designed as a base station transceiver and thus has specific features required for this like power amplifier and external RF front-end control ports.
If you’re looking for a cheap high-bandwidth SDR, LimeSDR is probably the best choice right now, if you’re looking for a high tuning range, USRP B2x0 is what you need, but if you’re building a telecom grade or embedded or outdoor system, UmTRX 2.3.1 is the only option right now.
We’ve put together a comparison table of the most popular SDR boards capable of full duplex operation, required to run a base station. Receive only or half-duplex SDRs like HackRF or rtl-sdr are not included into this table for this reason.
|Tuning range||70 MHz - 6 GHz||300 MHz - 3.8 GHz||30 MHz - 3.8 GHz||300 MHz - 3.8 GHz||300 MHz - 3.8 GHz|
|Sampling rate||12-bit 61.44 MSPS||12-bit 40 MSPS||12-bit 61.44 MSPS||12-bit up to 40 MSPS (13 MSPS default)||12-bit up to 40 MSPS (13 MSPS default)|
|RF bandwidth||up to 56 MHz||up to 28 MHz||up to 61.44 MHz||up to 28 MHz||up to 28 MHz|
|Industrial temperature range||no||no||no||yes||yes|
|Channels||1 (2 on the same frequency for B210)||1||2 (same frequency only)||2 (independent frequency)||2 (independent frequency)|
|Power amplifier control and monitoring||no||no||no||no||yes|
|Price||$686 - $1,119 + $636 (for GPSDO)||$415||$299||$950||$1300|
|Price per channel||$560 - $715 + $636 (for GPSDO)||$415||$150||$475||$650|
|Frequency stability||2 ppm||1 ppm||2.5 ppm||0.1 ppm  without GPS lock, <0.01 ppm with GPS lock||0.1 ppm  without GPS lock, <0.01 ppm with GPS lock|
|GPS synchronization||Addon (+$636)||no||no||on board||on board|
|Interface||USB3||USB3||USB3||Gigabit Ethernet||Gigabit Ethernet|
|Max output power||10 dBm||6 dBm||10 dBm||20 dBm @ 900 MHz, 17 dBm @ 1800 MHz||20dBm|
|Osmocom and OpenBTS support||yes||yes||no||yes||yes|
UmTRX 2.3.1 vs UmTRX 2.2
UmTRX 2.3.1 use the same key technologies and thus should be very familiar for existing UmTRX users. It is also dual-channel SDR transceiver based on two LMS6002D chips, equipped with an onboard GPS and using Gigabit Ethernet as a communication interface. The same UHD host driver and even the same FPGA firmware is used for both boards. At the same time UmTRX 2.3.1 features a number of improvements and new features important for embedded environments and for building complete base stations.
Main differences between UmTRX 2.3.1 and UmTRX 2.2 include:
Flat 100mW output power up to 4GHz.
Only pinhead connectors for optimal space usage.
Durable yet compact MCX connectors instead of U.FL in UmTRX 2.2.
Smaller size: 128x95mm vs 159.5×99.5mm for UmTRX 2.2.
- Connectors for power amplifiers with software regulated power supply voltage and output power and VSWR monitoring.
Better power efficiency thanks to updated DC/DC converter circuitry.
Most tantalum capacitors replaced with MLCC for higher MTBF.
Improved heat dissipation thanks to 90% copper filled bottom side and better mounting holes placement (pictured above with a mounting aluminium plate).
Better RF performance thanks to RF channels shielding, dedicated ultra-low noise LDO for LMS6002 chips and clocking circuits, DC/DC converter synchronization to RF sampling clock.
Input and DC/DC output voltage monitoring ADCs.
True remote board control through the Ext Panel connector, including full board power down.
RS232 debug port instead of USB in UmTRX 2.2 for higher reliability.
Up to 40 MSPS RF sampling rate with an external clock (limited to 30.72 MSPS over the wire aggregate sampling rate due to 1GbE bandwidth) compared to up to 20 MSPS in UmTRX 2.2.
- Few other minor changes to improve robustness.
You can find more information about UmTRX 2.3.1 in its datasheet.