LIFE ABOVE 70CM?

Dale Hughes VK1DSH Canberra Region Amateur Radio Club 26 September 2012

Tonight's ‘random walk’ will cover:

• What bands do we have from 70 cm up?

• What type of modes and activities are there?

• What type of equipment is used?

• Field day activities.

• Suppliers & resources.

Amateur Bands:

P = primary, S = secondary • • • • • • • • • • • 430 – 450 MHz (S) 1240 – 1300 MHz (S) 2300 – 2302 & 2400 – 2450 MHz (S) 3300 – 3600 MHz (S) 5650 – 5850 MHz (S) 10.0 – 10.5 GHz (S) 24.0 – 24.05 GHz (P) & 24.05 – 24.25 GHz (S) 47.0 – 47.2 GHz (P) 76.0 – 77.5 & 78.0 – 81 GHz (S), 77.5 – 78 GHz (P) Several bands up from 122 GHz both P & S Optical communications

Most commonly used bands

• 70 cm (432 MHz) • 23 cm (1296 MHz) • 13 cm (2.4 GHz) • 3 cm (10 GHz) • Some activity on all bands at various times.

• In general things get more difficult as you go higher in frequency…

Modes

• The microwave bands allow the use of very wide band modes as well as the traditional narrow band modes.

• Analogue & digital TV transmission.

• Data modes, ‘JT’ and other weak signal modes.

• FM & SSB commonly used for voice.

• Satellite & EME.

Activity

• The higher bands (above 23 cm) are used more frequently during field days from high locations – ‘mountain topping’ • Some home stations on 3 cm and possibly the other lower microwave bands, but uncommon. • Although there are a few well equipped 3 cm home stations in VK3 who use rain scatter etc.

• Use can be made of suitable reflectors e.g. Black Mountain tower. (More to follow…)

Using ‘mirrors…’

• Successful 3 cm QSO between VK1BL & VK1DSH via non-line of-sight path across Canberra.

• Direct path not usable due to hills between ends.

• The Black Mountain tower is an excellent mirror!

• A 3 cm net would appear to be possible.

Records: not just short distances!

• • • • • • • • • • • • • • National 432 MHz Digital Modes: VK4EME to EA3XU, 16855.4 km, 3/7/2010 National 1296 MHz Digital EME VK7MO to G4CCH, 17383.3 km, 29/4/2006 National 1296 MHz mobile: VK3PF to VK5BC, 933.7 km, 15/1/2011 VK1 2.4 GHz: VK1BL/1 to VK3ES, 424.9 km, 9/4/2012 National 5.7 GHz Digital Modes: VK9NA to ZL1TPH, 747.5 km, 16/1/2011 World 10 GHz EME: VK2ALU to G3WDG, 17000.4 km, 18/08/96 10 GHz Digital EME VK3XPD to VK7MO, 592.2 km, 9/5/2012 24 GHz Digital Modes: VK3HZ to VK7MO/2, 461.7 km, 19/06/12 National 47 GHz: VK3NX to VK3QM/3, 91.6 km, 03/06/12 National 76 GHz: VK3KH and VK3XPD, 11.9 km, 22/8/2011 National 122 GHz: VK3KH and VK3XPD, 1.5 km, 21/8/2011 National 134 GHz: VK3XPD and VK3ZQB, 50 metres, 23/10/2011 National 241 GHz: VK3XPD and VK3ZQB, 50 metres, 23/10/2011 National 324 GHz: VK3KH and VK3XPD, 25 metres, 23/10/2011 http://www.wia.org.au/members/records/data/documents/VHF%20Records%20History%20120816.pdf

Equipment

• Home brew: mostly transverters, some kits available. From simple to complex.

• Commercial: Lots available!

IC910 Pictures from www.rigpix.com

Advanced Receiver Research TR10GA – 10 GHz

Most common method: Transverters

• 144 MHz IF using IC202, FT817 etc. sometimes 28 MHz or 432 MHz is used.

• Issues… stability, frequency calibration.

• Relatively simple & inexpensive to construct.

• Examples 70, 23, 13 & 3 cm.

• GPS locking etc.

Typical transverter: Block diagram

3 cm with Gunn diodes

• The old way; using gun diodes or even Klystrons for wideband FM working.

• Simple to build with 30 MHz IF.

• Generally low power.

• Probably not common, but commercial equipment e.g. Polarplexers are sometimes available – even ‘door openers’ can be used.

• Simple but fun!

Gunn diode transceiver block diagram

• The transmitter also provide the receiver L.O

• Low power, but good range depending an antenna.

• AFC locks both ends to the same frequency.

• Full duplex mode.

Field day activity

• Three VHF/UHF field days each year: spring, summer & mid-winter.

• Many stations active on these days.

• Great fun!

• Many good high sites in area, ideal for microwave contacts.

Spring

2007 near Gunning 2011 near Gundaroo

Summer

2011 near Gundaroo 2005 near Gundaroo 2009 Mt Ginnini 2012 near Gundaroo

Winter

2008 Mt Ainslie 2009 near Gundaroo 2010 near Gundaroo

Resources/Suppliers

• Gatherings… Gippstech • Books: RSGB & ARRL handbooks.

• Suppliers: • http://www.minikits.com.au/ • http://www.downeastmicrowave.com/ • The web.

• Local contacts.

Conclusion

• Lots of interesting bands for UHF & microwave activities.

• Technically challenging, but not beyond amateur capabilities. • Field days are excellent opportunity to use such equipment – great fun too!

• So

there is life above 70 cm

, for the adventurous at least!

Thanks to…

• Andy VK3ES ex VK2AES • Ted VK1BL • Russell VK1JRM • Andrew VK1DA/VK2UH • Dimitris VK1SV • Peter VK2EMR • John VK1BEK • Lyle Patison VK6ALU ex VK2ALU • Plus all the other active stations during field days.

The end

• Questions?

• Thank you!