After years of research and dozens of experiments we would like to present you our version of SDR. This compact, light, sophisticated piece of hardware turns your computer into a modern, State-of-The-Art all mode Transceiver, giving you features that go far beyond the possibilities of any stand-alone mobile radio.
• One board 15 Watt SDR transceiver
• Optimized low noise DDS module
• Internal TCXO
• New Tx mixer
• Standalone one chip Pre-amplifier
• Embedded antenna switch + two Tx/Rx antenna connectors
• USB interface and FPGA control circuits
• 100W PA (two RD100HHF)
• Internal ATU
• VHF/UHF converter
Single board 15Watt SDR transceiver
The SDR-2000.ua is outfitted with individually optimized BPF to cover both the ham bands and for general coverage reception. These individually tuned filters minimize potential interference from strong out-of-band signals. Basic PA based on RD06HHF and RD16HHF transistors has ALC circuits. LP filter and 100 Watt optional power amplifier placed on the second board, under “main” board (not shown here). The real power of the SDR-2000.ua is unleashed when it is combined with FlexRadio's PowerSDR software. www.flex-radio.com
Optimized DDS module
First of all, all power and ground circuits of PA, DDS and mixer were re-routed. DDS output filter was completely changed. New filters for I and Q channels gave better phase characteristic, which improve IQ balance in modulator/demodulator while tuning. Usage of transformers present perfect galvanic separation between DDS and Tx/Rx ground circuits.
Here is some result of modifications, done in DDS module. For comparison, we prepared measurement data from other TRCVR also.
SDR LO output, DS90LV028 pin #7 (Span 2kHz)
SDR LO output, DS90LV028 pin #7 (Span 40kHz)
Elecraft K3 output LO1 (Span 2kHz)
FT1000MarkV field output LO1
As you can see, phase noise DDS in near zone is better than 20dBc/Hz.
Internal TCXO for Stable Frequency Operation
Equipped with a temperature compensated crystal oscillator (TCXO) to provide the frequency stability needed for digital and CW mode operation, the TCXO has low level of phase noise and achieves frequency stability better than ± 0.1 ppm over the operating
temperature of the transceiver once calibrated to a known frequency source, like WWV.
Signal spectrum on the TXCO output
Standalone one chip Pre-amplifier
Build on SGA6289 chip. Pre-amplifier might be programmed by using “External control” settings in PowerSDR software. Use “pin #5 for pre-amp.
On 40-30-20-17-15-12-10 bands pre-amp will be always switched on.
Embedded antenna switch + two Tx/Rx antenna connectors
SDR-2000.ua has internal antenna switch for two antennas. User can easily choose and
program antenna for Tx and Rx modes separately, by using “External control” settings in
PowerSDR software. Use “pin #6 for ANT switch.
-160 meters – ANT1 used for Tx and Rx
- 80 meters – ANT2 used for Tx and Rx
- 40 meters – ANT2 for Rx, ANT1 for Tx
USB interface and FPGA control circuits
One of the technological innovations SDR-2000.ua was USB interface and internal
peripheral bus, controlled by FPGA. Both this features introduced decrease of noise
level, spurious pulse and save onboard space.
The ATU will tune a variety of unbalanced antenna systems (coax) that facilitates its use
with multi-band antennas where the SWR is less than or equal to 3.0:1 (dependent on
the complex impedance of the antenna). When used with an appropriate balun,
balanced antenna systems can be utilized also. The ATU, when tuned and enabled, is
also in the RX signal path further enhancing reception. An ATU bypass function will
completely remove the ATU from both the TX and RX signal paths. All ATU functions
are automatically controlled using FlexRadio PowerSDR as well as having manual
control of the ATU.
Network Type: Switched "L"
Impedance Range: 17 to 150 ohms
Power Rating: 100 watts 160-6m
A compact footprint makes it perfect for fixed and portable operating positions
One of the first things you will immediately notice about the SDR-2000.ua is its compact
(300 x 200 x 35mm) dimensions. One of the advantages of the compact footprint is that
it allows for multiple installation configuration options. It can sit underneath a laptop, it
can be installed oriented vertically on its side to save desk space and can even sit
underneath a desktop monitor.
All measurement made on one RF test board:
Mixer - FST3253MTC
LF driver - DRV135UA
HF trans - Т4-1 Mini-Circuits
Balance mod - AD5263
Equipment used for measurements: Spectrum analyzers Tektronix RSA3308A, Service
monitor Agilent HP8935 and other.