0. The

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0. The µWave SDR
By Jonathan Naylor, ON/G4KLX
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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 arent
  computer specialists

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2. The Team

• Neil Whiting, G4BRK
• Chris Bartram, GW4DGU
• Jonathan Naylor, ON/G4KLX
• Grant Hodgson, G8UBN
• Tobias Weber, DG3YEV

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3. The Concept
TX
µWSDR 1
RX
TX
µWSDR 2
RX
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4. Unified Hardware

• Use the latest commercial ICs/modules
• 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

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5. Front-Ends

• Basic specifications
• 100 - 200mW 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

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

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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

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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

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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

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

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13. Back-End Software

• Implements a complete UDP/IP stack
• Simple command interpreter
• Possibility of hardware AGC

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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

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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

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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

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17. SDRSetup

• Sets up the UWSDR hardware

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18. GUISetup

• Creates or changes an instance of the GUI
• Sets up external connection information,
  dependent on the type of SDR chosen

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19. SDRHelp

• Help available for the other programs
• Available from within the GUI

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20. The GUI
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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

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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

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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

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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

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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

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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 http//www.uwsdr.net
• E-mail naylorjs_at_yahoo.com