1. 0. The µWave SDR
By Jonathan Naylor, ON/G4KLX

2. 1. What Is The µWave SDR? Cheap access to microwaves
Use the best of modern technology
DSP to give great performance
Small form factor for remote mounting
Keep it simple - most microwave ops aren’t computer specialists

3. 2. The Team Neil Whiting, G4BRK Chris Bartram, GW4DGU
Jonathan Naylor, ON/G4KLX
Grant Hodgson, G8UBN
Tobias Weber, DG3YEV

4. 3. The Concept TX
µWSDR 1 RX
Switch PC TX
µWSDR 2 RX

5. 4. Unified Hardware Use the latest commercial IC’s/module’s
Same devices across bands
Two part hardware, a common back-end and a band specific front-end
Together Eurocard sized to fit into standard extrusions/cases

6. 5. Front-Ends Basic specifications:
mW RF output
2 - 3dB Noise figure
Simplifies design, reduces cost and engineering complexity
Fits in well with modular designs
Can be used barefoot and still be effective

7. 6. Front-End Block Diagram
RF In
I/Q Out
BPF
LPF
10 MHz
Osc. Control
RF Out
I/Q In
BPF
Control Out
Control In

8. 7. Front-End Specifics 1/2
Single Fraction-N synthesizer chip chosen, the LMX 2486
Divided for lower bands, thereby reducing phase noise
External high quality 10 MHz source is possible
Commercial of home made VCOs

9. 8. Front-End Specifics 2/2 Highly integrated RX and TX mixers:
RX – LT 5575, LT 5517
TX – ADL 5372, ADL 5385
Three layer PCB, oscillator on one side, RX and TX chains on the other
Commercial or home made bandpass filters

10. 9. Design Challenges
Microwave band activity areas are narrow, but they may not be the same worldwide
23cms – 1269/1296 MHz
13cms – 2304/2308/2320/2400/2424 MHz
9cms – 3400/3456 MHz
This complicates the design of VCOs and bandpass filters

11. 10. Back-End Interface between the PC and the Front-End
One per front-end, tightly integrated
Converts base band to ethernet packets and vice versa
Takes commands to control the oscillator and external devices
General purpose CPU for flexibility

12. 11. Back-End Block Diagram
I/Q In
ADC AKM5394a
DAC/ Clock PCM1740E
I/Q Out
CPU
AT91SAM7X256
Ethernet
Osc. Control
Control Out

13. 12. Back-End Hardware
CPU is a 60 MHz ARM7 core with integrated Ethernet, programmed in C
ADC is AKM5394a operating at either 48 or 96 Ksps
DAC + Clock is PCM1740E, feeds clock to the ADC, speed under software control

14. 13. Back-End Software Implements a complete UDP/IP stack
Simple command interpreter
Possibility of hardware AGC

15. 14. The Ethernet Protocol All messages use UDP/IP
All messages have a two character identifier
Data messages have a sequence number to discard out-of-order packets, no retries
Command messages have explicit ACK/NAK
Command messages are transported with a simple stop-and-wait protocol

16. 15. Why Ethernet?
Longer distances than USB, important for /P and remote mounting of hardware
Less HF interference than USB
Simple to extend with fibre optic
A more portable API on computers

17. 16. µWave SDR Software A suite of four programs:
The GUI
SDRSetup
GUISetup
SDRHelp
Very simple to install and use
Completely cross platform, Windows, Linux and Mac OS X

18. 17. SDRSetup
Sets up the UWSDR hardware

19. 18. GUISetup Creates or changes an instance of the GUI
Sets up external connection information, dependent on the type of SDR chosen

20. 19. SDRHelp Help available for the other programs
Available from within the GUI

21. 20. The GUI

22. 21. GUI Features Uncluttered design and easy to use
Looks similar to existing radios
Runs on small-ish computers
Supports multiple hardware types:
UWSDR
SoftRock (RX and RXTX)
Demo mode

23. 22. GUI Internals DSP core based on DttSP but converted to C++
Removed esoteric features
Added Weaver method
I/O via interfaces making the addition of new hardware simple
More tightly integrated than DttSP, more like PowerSDR

24. 23. GUI Usage
Less used features are hidden away, similar to the IC-706
Spectrum display is adjustable
S/Power Meter is adjustable
CW/Voice keyer
Has the concept of default bandwidth, AGC speed and tuning speed per mode
Target audience are not computer geeks

25. 24. 3cms SoftRock RXTX?
Fixed LO based on WiMAX VCO and fractional-N synthesizer
Passive bi-directional mixer
Integrated patch antenna for dish mounting
-6 dBm RF output (250 µW)
10 dB noise figure
Great for /P use on hills/mountains

26. 25. µWave SDR Progress
Software is mature and in use on-air with SoftRocks
Back-end is progressing well, currently evaluating new Ethernet hardware
Front-Ends are not so advanced

27. 26. Contact Software is under the GPL
Hardware will probably use the TAPR OHL
If you would like to help the µWave SDR project, either hardware or software
Web page: