Amateur Radio November 2013
Delivery expected from October 24
 WIA Member Digital Edition Download
Editorial
Publicity for our hobby
A few days ago I received a copy of the front page of a local government publication. Much of the page was taken up with a story of a group of local amateurs who activated a nearby lighthouse as part of the International Lighthouse & Lightship Weekend in August. It gave some details of those involved and their activities, including two good photographs.
It is terrific to be made aware of such instances of positive stories about our hobby. However, those that send in such stories must recognise that we are unlikely to be able to use the material within these pages. The most important point is that the material has already been published and is protected by copyright. Any republication would require written permission from the owner/s of the copyright.
The material was supplied as a hard copy. Even if we had permission to use the material in AR, we would not be able to use the images – even if we scanned the images, the quality would be insufficient for our needs. We would also need to completely retype the text in this case, as the text ran across part of one of the images.
How to contribute to AR
Whilst the notes have not been updated for some time, we have had details of how to contribute to AR available on the WIA website for several years. Simply find your way to the AR magazine pages in the “For Members” drop-down menu. Near the top of the left hand menu is a link “Contributing material”.
That link will take you to an overview of how to contribute. At the bottom of the page are two documents available to download: “How to write for AR magazine” and “A word about photographs”. Please read the page and these documents, preferably before you start writing. Please note we much prefer to receive material in electronic format, with documents preferably as Word files and images as JPEG files, preferably at least 1 MB per image. Technical drawings have their own separate requirements and the web page provides guidance as to how they might best be prepared.
Think about what you might contribute well before you commence your project or before the event you plan to describe. If you plan ahead, you can consider how you can ensure that you have good quality, high resolution images available to illustrate the story. Always set your camera to take and then store the image at the highest possible resolution, preferable in a RAW format if that option is available.
What to contribute?
We prefer to have a mix of news, general stories related to amateur radio and technical articles. For many readers, preparing a technical article might seem daunting. However, feel free to write up your latest project – our team can offer you guidance and/or polish your writing. Take some good high resolution photographs. Most people can send jpg images of at least 1 MB size via email. If you are unsure, simply contact us for guidance or copy all your files to a CD and post the CD in to the WIA office. If using the postal method, always include your highest resolution images on the CD.
Remember that we are always looking for stories and good images. It may be several months before your contribution appears in print, but it may appear in the next issue to be produced, depending upon content at hand here and the timeliness of your story.
Remember that all material needs to be in our hands by the first of the month of the month prior to the cover month on the magazine.
Until next month,
Cheers,
Peter VK3PF
This month’s cover
This month our cover shows Keith VK5OQ/3 operating at Mount McKay near Falls Creek in Victoria. Mount McKay is SOTA summit VK3/VE-007. Keith gives us an account of his ski trip to Mount McKay in the story on page 6. Photo by Ian Ritchie.
WIA President's Comment
Radcomms 2013
Phil Wait VK2ASD
Every year the ACMA hosts a two-day Radio Communications Conference featuring a series of speakers from various industry sectors, and the ACMA, covering a broad range of topics. Several “panel sessions” provide an opportunity for audience interaction. It is a valuable opportunity for the WIA to interface with industry and gain insights into the future directions of radio communications. WIA Director Roger Harrison VK2ZRH attended day one, and I attended the second day. These are our combined observations and comments.
Although the event was subtitled “4G and Beyond”, to emphasise the role of mobile broadband technologies, the subject matter covered quite a lot more than that, including: competing demands for access to spectrum; the value of spectrum to the government, the economy and society; the rapidly changing uses of spectrum; the role of broadcasting; innovation in spectrum use; and the future role and work of the ACMA.
In opening Radcomms 2013, the Chair of the ACMA, Chris Chapman, highlighted the issue that “. . . regulation must be responsive to innovation” and the fact of tension between interests in spectrum access where divergent views collided. To stay abreast of developments and the requirement of the ACMA “. . . being an evidence-informed regulator”, he outlined two studies commissioned to contribute to the agency’s future work: one being on forecasting likely future demand for spectrum, the other on the impacts of mobile broadband technologies on the Australian economy and society. Two speakers provided insights into preliminary results of these studies, which highlighted the rapidly changing impact that wireless devices have in everybody’s work, living and leisure activities.
Panel members were quizzed about attitudes to the licensing system and the concept of “parameter-based” licensing was raised, creating some lively debate. This idea does away with the current system of apparatus, class and spectrum licensing, and regulates access to and use of spectrum by specifying a list of parameters (in much the same way that LCDs do, for example).
Rob Fitzpatrick from NICTA, Australia’s Information Communications Technology (ICT) Research Centre of Excellence, gave a presentation on aspects of NICTA’s current R&D work, in which he pleaded the case for having “sandpits” of unlicensed spectrum for researchers to “play with” as needed from time to time.
The Secretary of the Department of Communications, Drew Clarke, gave a talk in which he canvassed the idea of “unchaining spectrum” to engender innovation; “what more can it do?”, he asked, raising the spectre of spectrum demand for uses as yet unimagined. Tellingly, he advocated the case for providing “adequate (spectrum) for public interest uses”.
Apart from anything else, the Radcomms conferences provide a valuable opportunity to network with ACMA staff and key people from industry and academia, and the WIA’s participation is always very well received.
Second day speakers discussed the future of traditional broadcasting, innovation in spectrum use, and where to from here. Speakers included representatives from Commercial Radio Australia who argued a case for more Digital Audio Broadcasting (DAB), especially in non-urban areas, and from Free-TV canvassing ultra-high definition free-to-air television broadcasting using high-definition and content-rich formats like MP-4, and linking the provision of free-to-air broadcasting (as opposed to paid subscription services) to healthy democracy.
Speaker Anthony Gherghetta, from the App Studio, cited the “internet-connected car”, a world of on-line motoring where you choose the streaming content prior to your commute to work, maybe starting with the local traffic report, BBC news world headlines, the latest country music hits and a bit of talk-back. Not to mention everyone will know where you are, and your credit card will automatically get debited if your right foot gets a bit heavy. Hopefully we will be able to remove that module!
All these applications are driven by strong public demand, and they have one very critical feature in common - they are all spectrum hungry. Conventional spectrum usage is inherently inefficient, with most frequencies being vastly underutilised. Just tune across any of the non-broadcasting bands and note how most frequencies are vacant most of the time. If any of the conference predictions come true, new ways must be found to increase spectrum efficiency and usage. New radio technologies and vastly different ways of thinking about spectrum will be required.
Cognitive radio is a technology where a transmitter and receiver negotiate with each other to find a clear frequency. Unlike the rigid fixed-frequency operation that we are all familiar with, cognitive radios continually negotiate with each other or as part of a network, seamlessly jumping around within defined frequency limits and communicating with each other, totally invisible to either primary users or to other spectrum users.
In the cognitive radio model, spectrum usage and spectrum efficiency is dramatically increased. Spectrum Brokers may purchase chunks of spectrum and re-sell it to cognitive users on a dynamic basis, but no user ‘owns’ any particular frequency.
So, in this brave new world of frequency sharing and dynamic spectrum allocation, where does all this leave amateur radio?
Several speakers explored the issue of the “value” of spectrum – the economic or monetary value, the political value and the social value. The concept of spectrum having an “imputed value” was raised in one panel session, along with the concept of certain spectrum bands and uses having an intrinsic or “intangible” value as a social good – not everything could be reduced to monetary value.
Amateur radio has a rich history of public benefit. Albeit through a fairly rigorous set of entry criteria, amateur radio already provides spectrum for public interest users and, since the very early years, amateur radio has exploited spectrum for experimentation, research and development. There are many examples from over the decades, where amateurs have explored radio communications concepts that have been subsequently developed into successful commercial technologies – cellular telephony being one telling example.
As Maureen Cahill from ACMA noted, “spectrum is the great enabler of the 21st century, ….with a projected 30 billion wireless connected devices by 2020, up from 10 billion today”. It may be in this ‘brave new world’ there is a renewed place for amateur radio as a protected public space, available through our system of individual amateur licensing, for public usage, education, research and other non-commercial purposes.
Radio Communications Conference attendance currently costs the WIA about $720 per year, not including any travel or accommodation expenses. WIA members fund this activity in the interests of all Australian radio amateurs.
Table Of Contents
GENERAL
A winter activation of Mount McKay for Summits on the Air (SOTA) Keith Gooley VK5OQ
Citadel Island Lighthouse ILLW 2013 Tim Buckley VK3MTB
Cape Willoughby Lighthouse, 2013 Paul Simmonds VK5PAS
Getting wire antennas into the air Graeme Dowse VK4CAG
More major developments in the WIA Award system Marc Hillman VK3OHM
TECHNICAL
Antenna coupler dummy load Warren Stirling VK3XSW
Using cheap CATV 75 ohm cable to feed amateur antenna systems Gary Gibson VK8BN
A light on your LDG AT-7000 auto ATU Steve Mahony VK5AIM
‘Ramsey QRP20’ with HRD and AM John Sutcliffe VK3TCT
Calibrated shorts Warren Stirling VK3XSW
Plus all the usual Club news and columns
A winter activation of Mount McKay for Summits on the Air (SOTA)
Keith Gooley VK5OQ
Another SOTA adventure, this time an activation of Mount McKay in wintertime – rather more than your average activation challenge given Mount McKay is more than 1,800 metres high, there is usually lots of snow at this time of the year, and temperatures regularly dip well below zero.
A good read for all, and surely one that will provide even more impetus for other amateurs to get ‘SOTA involved’.
Getting wire antennas into the air
Graeme Dowse VK4CAG
Getting a wire antenna (notably a dipole) into the air is not a terribly difficult chore most times – but if you want it high, and perhaps placed precisely, in an area not described as the norm, sometimes it is a dreadfully difficult task.
This short article introduces little that hasn’t been seen before, but is an interesting read on how one amateur attained a degree of self-satisfaction with his idea on how to simplify the task, and implementation thereof.
Using cheap CATV 75 ohm cable to feed amateur antenna systems
Gary Gibson VK8BN
This article questions whether it is absolutely necessary to use 50 ohm cable for feeding amateur antenna systems, given its relative expense versus similar performing 75 ohm cable that was, in fact, significantly cheaper.
The argument put by the author, whilst quite straight forward, does make a reasonable case for using the cheaper cable.
Antenna coupler dummy load & Calibrated shorts
Warren Stirling VK3XSW
This month we have two articles by this author.
The first explains how to build a multi-purpose dummy load, one that would allow testing of most practical HF antennas and therefore overcoming the risk of inconveniencing others by having to actually test whilst on-air.
Whilst a seemingly simple wish for the project, the requirement of needing all components to be capable of handling whatever load was applied to them meant that a good deal of thought had to be undertaken to ensure that parameter was achieved.
In the second article, the words of the author probably speak best – ‘I recently added a return loss bridge to my collection of test equipment and was discussing its use and application on the morning drive time net on VK3RCC when it was suggested to me that shorting the common port during the calibration procedure would be better than leaving it open (my test equipment requires the bridge common port to be either shorted or open during the calibration phase)…’.
The article explains how he home brewed these calibrated shorts, and the results obtained.
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