Portable Operations of
VK3BJM.
Q: What
makes a pleasant change to sitting in the shack waiting for rare DX?
A: Going out
to become rare DX!
Few things can beat sitting atop a faraway hill,
working DX via AEP, MS, or “Tropo”. And
it is easy to do – going portable can be as simple as taking away a 2.5w 2m
multi-mode rig and a 5 element Yagi.
Using such a set-up, and during very ordinary “Tropo” conditions, I have
worked stations nearly 300km away.
Using larger antennas, more transmitter power, and enhanced propagation
conditions will mean your signal will go much further – much, much, much, much
further!
There are plenty of good reasons to go out and try
portable operations. Here are a few:
[1] You can get to operate away from sources of RF
interference and noise;
[2] It’s one way of reducing the chances of causing
TVI;
[3] The opportunity to operate from picturesque
locations;
[4] Activation of inactive Maidenhead Grid Locators
(Grid “Squares”);
[5] Maximise the opportunities
presented by the various propagations modes available;
[6] Stir up activity in general – what I refer to as
the “Moving Target Syndrome”.
Three propagation modes dominate VHF and UHF
activity in Australia: AEP, Tropo “Ducting” and Tropo Scatter. Most contacts between Melbourne and the
Canberra/Sydney area are achieved by AEP.
“Ducting” provides the mechanism for most contacts between Tasmania and
the mainland, and for those between the Eastern and Western states. The majority of short to medium distance contacts
occur via Tropo Scatter. And all in
all, most of these contacts occur following the concentration of population
around the coastal strips of Australia.
Meteor Scatter comes in next in the popularity
stakes. Recently computer programs such
as Joe Taylor’s WSJT has made MS much easier to take advantage of, but a couple
of years prior to its arrival I became interested in trying to take advantage
of it to enable voice contacts from areas that had no active VHF or UHF
amateurs. I’d already had experience
taking equipment out to participate in “Field Day Contests”. I wanted to try operating from unusual and
remote locations. At first it was
simply the challenge, but this soon shifted to proving that signals were not
heard from those locations because there were no stations operational there,
not because propagation did not exist.
The first trips to activate rare Grid “Squares” did coincide with contests: Wilson’s Promontory in January 1998 (Grid “Square” QF30); and Gwynne Hill (also known as Mt Boomanoomana) near Mulwala, NSW in March 1998 (Grid “Square” QF24).
Next was the activation of QF16, which I did from near Lake Mungo, NSW, in May 1998. This trip only involved 144MHz but I had upgraded to a 60-watt power amplifier in lieu of the 25-watt amplifier I had previously used. This was just as well as propagation back to Melbourne was difficult and I needed all the power I could muster to complete the contacts that were made. At that stage I operated in the late evening, and hadn’t thought outside using tropo “ducting”. It wasn’t until 2001 that my eyes were truly opened to the other possibilities…
In October 1999 I bought a 160-watt power amplifier, and not long afterwards I upgraded my transceiver from an old Yaesu FT-290r MkI to a new Icom IC-706 MkIIg. This was a significant improvement: not only was it a major increase in transmitter power, but the IC-706 had a more sensitive receiver, and the power amplifier also contained a 21dB receive pre-amplifier. I could hear better, and call better. The IC-706 also had the 432MHz band included, and I added a separate 100-watt power amplifier for that band.
Most of 2000 was spent working in Sydney, and while there I thought I’d have a go at working back to Victoria from near Bathurst – activating QF46 in the process. I set up in the afternoon, and had a couple of attempts to contact Chas Gnaccarini VK3BRZ at Lara (near Geelong, VIC). We had no luck via AEP or tropo, but during the evening (between 8 and 10pm) I listened on the Mt Anakie 144MHz propagation beacon frequency. During the period I counted about 20 “pings” – brief bursts of enhancement, from meteors burning up in the atmosphere, allowing the beacon signal to be heard. When Chas returned after 10pm, we discussed this and agreed to attempt a contact using MS early the next morning. The plan was for me to listen for the beacon and, when a burn commenced, (quickly) switch to our calling frequency and call him. Luck was on our side, and we had a burn within the first 15 minutes that allowed a successful contact.
Once back in Victoria at the end of 2000, I thought about timing a trip to coincide with one of the handful of annual meteor showers that are visible in the Southern Hemisphere (we get far less showers than the Northern Hemisphere). This would give me one more propagation mode to utilise. I chose an area 60km northwest of the western NSW town of Ivanhoe, in the Manara Range. This was a small range of hills that had an average height about 85m above the surrounding plain. It was about 700km drive from Melbourne and there was no chance to reconnoitre – I hoped I’d find an easily accessible high spot. There were none on public land, but again I was lucky. I found the nearest station homestead, and fortunately the owner agreed to let me have access to the highest point in the range (which was on his station). I set up on Mt Manara (Grid “Square” QF17) in the mild autumn sun and marvelled at the view. At 175m above sea level, the view was unobstructed to the horizon – simply fantastic!
Not so fantastic was the propagation. That evening I managed one contact with Charlie Kahwagi VK3FMD in Melbourne – and only succeeded by resorting to using Morse code rather than voice. No meteor pings, and almost no assistance from tropo. The next morning I was contacted on a HF liaison channel and asked to point my antenna towards Sydney. No expecting much, I did as requested. Almost immediately I was told my CW beacon signal was audible, and quite loudly! I went to voice and completed a contact with Gordon MacDonald VK2ZAB in Berowra Heights, north of Sydney. The signal faded down, so I switched my CW beacon back on. Before too long the signal reappeared, and we completed a contact at 432MHz. When the enhancement was present, the signals were very strong – but nothing was heard between times. With the aid of Alan VK2DXE, who was my Sydney liaison contact and fortuitously lived within sight of Sydney Airport, we established that we were benefiting from AEP courtesy of Boeing 747 aircraft heading west from Sydney. Before the morning was out, I completed a 144MHz contact with Alan, too.
The result of this was 3 years of research and trips, plotting the aircraft tracks on maps and using them to help predict where contacts would be likely from. This research also identified aircrafts tracks that would provide propagation back to Victoria. Many contacts took place in this period, which culminated in a successful trip to a spot 100km north of Broken Hill called Fowlers Gap (Grid Square QF08). Contacts on 144MHz to Sydney (at a distance of 923km), Melbourne (882km) and Canberra (860km) were made. A two-part article detailing this research and the resultant trips appeared in the October 2005 & March 2006 editions of the WIA magazine, “AR”. With thanks to the editor at AR, Part 1 and Part 2 are viewable in PDF.
A couple of trips have also been made into the Flinders Ranges area in South Australia; these are now documented on the “Portable Operations II” page.
Updated 25/5/2011
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