On the weekend of 11/12 July 2015 I made the annual pilgrimage to Gippstech 2015. Held at the Churchill Campus of the Federation (formerly Monash) University.
The conference focuses on Microwave and Weak Signals but has a broad range of topics that would appeal to many amateurs. About 130 people attended with about 90 attending the Saturday night dinner at the Morwell Workers Club.
Full marks to the Eastern Zone Amateur Radio Club and Convener Peter Freeman VK3PF for another inspirational GippsTech.
Thanks also to Rex VK7MO who I hitched a ride with – yet again!
SATURDAY 11 July 2015:
We started with David Rowe VK5DGR the creator or FreeDV giving a presentation on Advanced VHF Digital Voice using Codec2 (FreeDV) and the new developments which has seen a bit rate down to 700bps or roughly 700/800hz bandwidth for acceptable SSB quality voice.
David took us through the applications with the SDRs on the market and how he is working to optimise the FreeDV to radio interface to take advantage of the mode. Flex have already compiled in the FreeDV mode and it is just another mode available via the radio.
David also showed his SM1000 digital microphone that is a microphone that used the Codec2 software to digitise the voice and provide a digital stream out the other side.
This presentation was video recorded and will be shown at the REAST presentation night on August 5, 2015 along with a demo.
Next was our very own Rex VK7MO who took us through his recent world record distance setting record on 10GHz over 2700km. This presentation was videoed for playing at a Microwave conference in the US later in the year.
Some earlier Youtubes of his exploits:
Then Lou Blasco VK3ALB and David Learmonth VK3QM gave a presentation on converting surplus 3.4GHz link gear to a 3.4GHz (9cm) transverter down to a 70cm IF.
Alan Devlin VK3XPD gave an update on the GPS Locked Beacon project that has seen between the WIA and VK3XPD giving $200 per beacon from 144 and upward and a total of 23 beacons were upgraded or put in with a total of $3000 paid. Alan is looking for feedback from beacon owners Another proposal from Alan – award for enthusiastic microwave amateur – newbies – “Alan Devlin microwave enthusiast award” – Nominated by peers and includes a cash prize.
Alan then gave an impromptu presentation on his recent trip to Freidrichshafen hamfest and the microwave DX opportunities they exploited. They operated on 10, 22, 47, 76, 122ghz as well as DC at 144 & 432MHz hihi in the 24 hours field day with Wolfgang DL amateur
Damien Ayres VK3KQ and Ralph Pankhurst VK3LL did a very humorous presentation on the LL/KQ electronic compass rotator controller. They ran through their investigations using the Tvtator and adding a compass into some rotator software PCTrotator.
Richard Gipps VK3ZCL took us through Band Stop Filters, designing using his P-Syn software that he has made freely available. He took us through the theory and the design.
Roger Harrison VK2ZRH – WIA Director took the audience through the latest challenges and changes for the Australian Radio Amateur 2015.
The following includes:
- Remake of LCD – including 3.4 ghz some going for NBN – WIA Wishlist is still on table
- WRC 15 2-17 November 2015 – possibly 5mhz access to channels?
- Possibly 77ghz with vehicle collision detection
- ACMA and radcom act convergence by the end of 2015
- Radical licence reforms including parameters based licencing – apparatus/class/spectrum going
- Spectrum access is an enabler of new technology
- Expectation of sharing – AR has decades of sharing with defence, ISM, land mobile
- Decades of exclusive use – new partners of sharing
- Spectrum three pillars economic, defence, societal
- Economic – infrastructure for commerce. Internet
- Defence – Comms and surveillance
- Societal – not for profit, community, personal value, education, science emergency, innovation and AR – wide industry support – how do you value?
- Improve links with defence and education
- Reform of the ACMA – core and Non-core functions. – spectrum user functions being assumed by the users
- Still need an umpire and outsource operations
- Band manager concept. – uncharted territory
- Brave new world
- Who writes the parameters – statutory role who ?
- WIA peak body with the ACMA – 32% higher than ARRL
Julie Gonzales VK3FOWL and Joe Gonzales VK3YSP gave a great talk on their Melbourne Amateur Radio and Technology Group (MARTG) entry into the 2015 Global Space Balloon Challenge (GSBC) and went through the hardware and software required. They setup the electronics and balloons in the show and tell area.
Russell Lemke VK3ZQB took us through his build of a CNC Milling machine and the components and way he put it together. Russell is milling PCBs, panels, signs and wood work. It demonstrated that you don’t need lots of programming or special interfaces as these are all readily available from you guessed it China!
- Mach3 software
- Lazycam conversion software
- Flatcam pub conversion
- Designspark RS components cad software
Dinner at the Morwell Workers Club.
SUNDAY 12 July 2015:
On the Sunday Glenn English VK1XX gave a great presentation on SDR and the weak signal user. Glenn presented all the different types of SDRs that are currently available and their strengths and weaknesses. He highlighted that it’s all about how the engineer has implemented the SDR circuit and it is possible to get a dynamic range approaching 120-150dB and many implementations blocking dynamic range
- Direct rf sampling– HPSDR – 30-35dB noise figure. – adc is much more expensive – Needs fpga to deal with the data
- If sampling – Superhet then if filter then into adc – adc at IF freqs can be less cost and performance eg. ICOM, elecraft, etc
- Complex base band sampling – eg. softrock
LPF determines the bandwidth of the system eg. 48khz – I & Q into L and R channels of the sound card – Simplifies the hardware to high performance set of mixers – minimum analog circuitry.
Other important SDR issues to consider:
- Adc overload is catastrophic
- Intermods behaviour is wildly different
- ADC quantisation noise – intermods are the same
- Audio convert range – 120-140dB
- Aliasing is evil in sampling and therefore we need antialiasing filter
- Try to operate down the nyquist spectrum
Best performance is the soft rocks type of SDR with a minimum of analog circuitry but protected adcs and the audio ADCs in sound cards can be VERY high performance.
- Separate radios with same clock on separate antennas and in software you can change phase and amplitude and therefore software steer the antennas plus and minus 30 degrees. If SDR devotee claims greater than 100 dB – be suspicious – you cannot measure that! Latency to several 100ms is a real problem with qsk performance on the radio.
Rex VK7MO then took us through his extreme Grid squares activity on 10 & 24GHz and I have videoed this presentation for the DATV library.
Doug McArthur VK3UM took the audience through the improvements to his software EMECalc and EMEPlanner.
Rex VK7MO gave a presentation on the developments with WSJT-X and I also videoed this presentation for the DATV library.
Roger Harrison VK2ZRH gave a very funny presentation on becoming a VK Classies-aholic – buying things from magazines and then online and becoming hooked. Roger finished with the affliction that many hams have – Obsessive Compulsive VK Classifieds Disorder with a warning “There’s no known cure!”
Justin VK7TW then gave a humourous presentation on his Novel Az-El mount for his 10GHz portable setup with apologies to W.Health Robinson and this was videoed for the DATV Library.
Chris Steers VK5MC finished up with a quick update on his SDR adventures and his EME experiments and his disappointment with using DVB-T USB RTL Dongles.
We wrapped up another great weekend and finished with Pizza and back on the road for the 150km trip back to Melbourne.
Thanks to Rex who was again my driver for the weekend in what turned out to be some very trying weather.
(73, Justin, VK7TW)