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Amateur Beacons for the 21 st Century

Amateur Beacons for the 21 st Century. Andy Talbot G4JNT / G8IMR September 2010. What is a Beacon ?. A Transmitter at a Known Location That transmits a prestored message, With Limited Information Content, Continuously, or Periodically, On a Known Frequency, For reception by anyone.

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Amateur Beacons for the 21 st Century

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  1. Amateur Beacons for the 21st Century Andy Talbot G4JNT / G8IMR September 2010

  2. What is a Beacon ? • A Transmitter at a Known Location • That transmits a prestored message, • With Limited Information Content, • Continuously, or Periodically, • On a Known Frequency, • For reception by anyone

  3. What do we want beacons for ? • Band openings, but there’s nobody on! • Is there anybody out there, is the band dead? • I can’t hear anyone, is it working? • Frequency Calibration • Antenna and Bearing setup

  4. What do we have now • HF Beacons • IARU Beacon chain • 14 - 28MHz, • Five Frequencies • CW and Power Stepped Carrier • – 10 seconds • Time Sequenced • Poor frequency stability / accuracy

  5. IBP Chain • Call Location 14.100 18.110 21.150 24.930 28.200 Operator • 4U1UN U- Nations 00:00 00:10 00:20 00:30 00:40 UNRC • VE8AT Canada 00:10 00:20 00:30 00:40 00:50 RAC/NARC • W6WX United States 00:20 00:30 00:40 00:50 01:00 NCDXF • KH6WO Hawaii 00:30 OFF 00:50 OFF 01:10 NOARG, HARC • ZL6B New Zealand 00:40 00:50 01:00 01:10 01:20 NZART • VK6RBPAustralia 00:50 01:00 01:10 01:20 01:30 WIA • JA2IGY Japan 01:00 01:10 01:20 01:30 01:40 JARL • RR9O Russia 01:10 01:20 01:30 01:40 01:50 SRR • VR2B Hong Kong 01:20 01:30 01:40 01:50 02:00 CRSA, HARTS • 4S7B Sri Lanka 01:30 01:40 01:50 02:00 02:10 RSSL • ZS6DN South Africa 01:40 01:50 02:00 02:10 02:20 ZS6DN • 5Z4B Kenya 01:50 02:00 02:10 02:20 02:30 ARSK • 4X6TU Israel 02:00 02:10 02:20 02:30 02:40 IARC • OH2B Finland 02:10 02:20 02:30 02:40 02:50 SRAL • CS3B Madeira 02:20 02:30 02:40 02:50 00:00 ARRM • LU4AA Argentina 02:30 02:40 02:50 00:00 00:10 RCA • OA4B Peru 02:40 02:50 00:00 00:10 00:20 RCP • YV5B Venezuela 02:50 00:00 00:10 00:20 00:30 RCV

  6. What do we have now • Other HF Beacons • Majority on 28MHz for Propagation alerts • 5.29MHz for propagation tests • Generally banned below 7MHz • Apart from occasional specials • VHF • Hundreds around the world • Simple crystal control, freq +/- tens of ppm. • Carrier and CW – callsign and locator

  7. Improvements • Design for Automatic Monitoing using PC / Soundcards • Narrow band • Want good frequency stability • Frequency Reuse • Time sequenced – helps QRM and regulatory issues • Simplifies auto-monitoring of multiple beacons • No Retuning

  8. Next Generation HF • Frequency Stability • Aim for better than 10-7 at HF (+/-1 Hz) • TCXO or Ovened oscillator • Minimise frequency clutter • Time sequence - like the IARU chain • Change the rules to allow beacons below 7MHz • Let technolgy reduce the QRM by • Precisely timed transmissions • Single frequency on each band, worldwide ?

  9. WSPR ?? • Already Well Established • Reporting Website in place • Automated reports • How About a Network of WSPR Beacons ?

  10. Data Modes • PSK31 or RTTY could carry information • Propagation state, band openings • Site telemetry • Unique time signature confirms reception • Time / Temperature / Pressure / ??? • Status of other beacons • QSL / Report Checking

  11. Next Generation VHF • Decent Frequency accuracy • Ovened crystal or GPS locked • Look for 10-9 accuracy (sub Hz) for auto search • Add weak signal data modes • JT65 • Extended period of coherent carrier for very narrow band integration • PSK reversals for time-of-flight mewasurement

  12. Microwave Beacons • Often Used when / Portable for : • Frequency calibration • Dish and Bearing setup • Propagation Monitoring

  13. Microwave Beacons • Frequency accuracy even more important as • They are often used for calibration • We need a lot more μWave beacons to ensure everyone can hear at least one on each band • Personal beacons • Attended or unattended • Licensing easier at microwaves

  14. What is needed – where shall we go? • Some Examples of next-generation beacons are already out there….

  15. The 5MHz beacon chain • GB3RAL GB3WES GB3ORK transmit in sequence. • 1 minute every 15 GPS timed • Power steps over 54dB for audible S/N estimation • TCXO frequency control (few Hz) • The system was designed for automatic logging (G3PLX software) • Cover a complete sunspot cycle

  16. 5MHz Automatic Propagation Monitor

  17. GB3SSS 1.96MHz / 3.6MHz • Temporary beacon for winter transatlantic propagation tests from Poldhu • 1 Nov to end Jan 2007 • Year later on 3.6MHz • Sequence similar to the 5MHz beacons • 1 / 15 minutes, power steps, carrier • PSK31 message – decoded in Canada • All waveforms generated in DDS chip

  18. GB3VHF 144.43MHz Wrotham, Kent • GPS Controlled frequency and time • JT65, CW, 1pps PSK • Two minute repeat cycle • Generic beacon driver concept • Up to 16 thirty second time slots can each be allocated to different modes

  19. GB3VHF GPS Disciplined Reference (12.8MHz) GPS Module DDS Source PIC Controller

  20. GB3RAL VHF Chain • 40.05 50.05 60.05, 70.05MHz • Phase coherent from GPS Locked master reference • JT65, CW, 1pps PSK • Two minute repeat cycle

  21. Bell Hill Microwave Beacons • Single site cluster of seven beacons for 2.3 to 47GHz and telemetry Tx on 70MHz • Evolutionary upgrades in capability • GB3SCS 2320.90503MHz JT4g GPS Locked • GB3SCF 3400.905000 MHz RTTY GPS Locked • GB3SCF 5760.905006MHz QRSS GPS Locked • GB3SCX 10368.9050068 MHz JT4g GPS Locked • GB3SCK 24048.905 MHz (CW only) OCXO • G8BKE/P 47.088905 GHz (CW only) OCXO • G4JNT/P 70.031MHz PSK31 Telemetry TCXO

  22. Bell Hill Microwave Beacons

  23. Beacon Hardware

  24. Several parts already exist in current designs • Driver / oscillator (but freq may need stabilising) • Power Amplifier (+ filters) • Antenna • But several new modules will be needed • Agile Frequency Source • Controller / keyer • Timing – eg GPS

  25. Power Amplifier • Power Steps, PSK31 etc need a linear PA • For low duty cycle time sequenced, simple class A or A/B MOSFET design is ideal • Broadband – so useable over multiple bands (beware filtering needs) • High duty cycle with no linear modes • Class C design is better suited. • Particularly at VHF / UHF • Frequency Multiplication

  26. Frequency Source • Crystal oscillator • Single frequency, no data modes • Poor Frequency Stability • Use oven or clip-on heater • DDS Directly useable at HF and low VHF • Spurii need cleaning up for higher frequencies • GB3VHF - additional crystal filter • μWave beacons, lock crystal oscillator to DDS O/P • Direct generation of most data modes • Clock from standard frequency reference (10MHz)

  27. DDS Sources • Older AD9850 / 9851 • Up to 30MHz directly. • FM / Phase modulation, • But no AM capability • Small and simple to use • 32 bit frequency register • ~ 10-9 freq setting • Internal x6 PLL for clock • AD9852 / 9854 • Up to 90MHz directly • Amplitude / phase / frequency changed in μs • 48 Bit - 10-14 Frequency setting • X4 – X20 Internal clock PLL • Even Faster devices eg. AD9950

  28. Controller • Simple CW Keyer • Tiny PIC

  29. More Advanced Controller • Microcontroller eg. PIC • ‘Workhorse’ 16F628 has enough power for most controller tasks • Reprogramme a Direct Digital Synthesizer in real time to generate data modes • AD9852 100μs to reprogramme (serial) • PSK31, JT65, FSK441 and RTTY demonstrated already. • Accept external data / telemetry inputs

  30. Timestamp the transmission with a unique code • Verifies correct reception at any given date / time. • Only the keeper knows the hashing key. • Simple to do in a PIC from the GPS data stream • Verifiable QSL – could this count as a one-way QSO !!!! • Alphanumeric code with pronounceable triads :- • 1800 JYC 1801 PUF 1802 KIC 1803 FOF 1804 WAC • 1805 PEF 1806 HAR 1807 CEG 1808 LUD 1809 RYG • 1810 MEB 1811 TAD 1812 CAB 1813 HED 1814 MIB • 1815 TOD 1816 ZUC 1817 FYF 1818 NAC 1819 WEF • May also have to send the minutes digit for correct time logging.

  31. Repeater Beacons • Add a receiver and data decoding • Decode your callsign sent to it • Reply with acknowledgement and report • Who will be the first ?

  32. Reverse Beacon • Instead of a Transmitter • Just a receiver with Internet Connection • You transmit to it • It reports to the web site, shows spectrum • There are a number of these at LF, • Ideal for antenna / transmitter tests • OR, phone up, transmit and listen • (Modest) premium rate phone number could finance it

  33. And talking of Finance..... • Beacons Cost Money • Site Rental (Bell Hill £500 per year) • Electricity (Bell Hill 200 Watts 24/7) • Operators travelling Costs for maintenance • And, of course, the hardware itself • http://www.scrbg.org/donate/ • Hamfest Stand

  34. Questions ?

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