The John Moyle Field Day is a Amateur Radio contest conducted once a year. It, along with the VHF/UHF field days represent the four major line of sight frequencies based contests in Australia. The John Moyle field days (JMFD) also have a substantial HF component that is not present at all on the VHF/UHF field days, and while it also allows activity right into the mm bands, typically operators are exiting stage left at 23cm or 13cm.
It’s a good contest for backpack portable because of the 6 hour section. It also rewards repeat contacts on CW and Digital modes, unlike the VHF/UHF field days. I am finding that I am able to operate chasing contacts nearly the whole 6 hours rather than lots of CQ’ing.
Mt Torbreck VK3/VN-001
Last year I participated in the JMFD from here, and I decided to do the same again this year. Mt Torbreck is the closest 10 point SOTA summit to Melbourne. It has no commercial radio equipment on the summit and is not accessible by road. There is only slight obstruction into Melbourne, so with a reasonable antenna, one can work HT stations on 2 and 70cm. The JMFD has a distance component, and Mt Torbreck is a good distance away to get many Melbourne contacts into the higher point distance bands. A number of JMFD stations also head southwest and west from Melbourne for the field day and this means that those contacts are high value. The EMDRC normally activate Mt Cowley as VK3ER for this contest and Mt Torbreck has LOS to Mt Cowley, about 222km away. Incidentially Mt Cowley is VK3/VC-022, but VK3ER drive to the top and use generators for their high powered station, so they are not a SOTA contact.
Mt Torbreck is accessible by a 2km walking track which climbs about 300m from the car park to the west of the summit. The walking track is steep and good shoes or boots are a plus. It takes about 50 minutes to climb up and 40 back + extra if carrying a lot of weight. I was carrying a lot of weight on this trip.
I normally plan to make two trips up because I have too much stuff for one trip. The stuff to be carried up includes:
- Yeasu FT-897 all mode rig
- Yeasu FT-817 all mode QRP rig
- 2 squid poles for a 2m and 70cm colinear antennas
- 6 1.5m al segments to make 3 times 3 metre poles for various antennas
- A turnstile antenna for 6m. This uses four 72cm M10 al segments with M8 taps to screw in 4 more 75cm segments to form two dipoles that are perpendicular horizontal polorization. There is an effective ugly balun for 6m near the feedpoint with a female UHF connector
- A quadruple quad antenna for 2m, which comprises of 10 al segments. There are two fiberglass poles about 50cm long to mount at the bottom and the top. This goes through a 2 PVC pipes that join together so that they are just over 2m long. This is mounted on the pole by a small al segment to offset it, and a bit of sticky tape to provide a shunt to ensure that the PVC remains vertical
- A similar setup on 70cm but here I have two quadruple quads
- 12 Turngy 3S 5000mAh LiPos. I put 3 in parallel x 2 in series when using them, so I effectively have two rounds of this
- A 12V down DC-DC converter sitting on the output of the LiPo array
- 3 Turngy 3S 2.2mAh LiPo packs to power the computer for a while
- A laptop with a supply that takes a 12V input
- 12 18650 lithum ion cells in 4 lots of 3 in series. Each one can be used to power the FT-817 for a while – my typical SOTA power setup
- A pile of Anderson Pole terminated power cables, including four 1 to 3 Y cables
- A collection of LMR195 and LMR400 cables. The 195 cables have either BNC or UHF connectors. The LMR400 are all N connectors. I also brought up a pile of converters. I typically use UHF on 6m and BNC/N on 2 and 70. The FT-897 has a UHF connector for HF/6 and an N connector for 2/70. The FT-817 has a UHF and a BNC connector which can be configured through the menus
- A one man tent to keep me out of the sun and the forecast showers
- A MiniVNAPRO and the extender to do some tests on the antennas to ensure all is ok
- Some plyers, shifters and other misc equipment to do any small repairs to equipment if that proves necessary
- A collection of HT radios for 2 and 70. The idea being to use these for FM on 2 and 70 for at least some of the contacts to save power
- Some headphones
- A CW touchkeyer
- A Signalink USB for digital modes, plus my Phone/Digital interface for a backup if required
For those who follow my SOTA activations, you would realise that this is far more than I normally take. You may realise why two trips are needed. Practically this means walking UP then DOWN then UP the mountain before the start of the contest, then DOWN then UP then DOWN at the end.
Upon arrival after the first accent, I put up the tent and piled the stuff in. Carrying all that LMR400 cable, the FT-897 and the 12 LiPOs certainly was a lot of weight and it took 1:10 to get up. I headed back down and got the remainder of the stuff, and it took 40 min down and 50 min up. First was getting the squid poles up. My 2m colinear has seen a lot of SOTA action, and a little stub I made up for 144.1 works well. Very low SWR – nice one. I use it without the stub on 146.5, with SWR around 2. With the stub for 144.1, 146.5 has a SWR around 3.
The 70cm colinear is short, with the good oil around 455MHz. I planned a stub for this to get 439 at least in the game, but I was not successful. There will be more about this in another blog post in the future, but for now I could not effectively use this colinear – what a shame because this was going to be the main game on 70cm vertical. I put up one of my whip antennas on the squid pole about half way up and fed it LMR400 cable back to the radio.
Next up was the 6m turnstile. This is pretty quick to put up. This is not a gain antenna, but it is enough to put me in the game on 6m and it can break up quickly to go in a pack. It gives an SWR below 1.5 at both 50.15 and 52.15
Here’s a pic of the 6m antenna in the foreground with the two squidpoles in the background, plus the operating tent. You can see the trig point to the right in the trees:
6m turnstile, plus 2 & 70cm colinears
The 2m quadruple quad was next. Last year I had two of these in an array, but they were too phyisically heavy to put up, so I jury-rigged up one. This year I did not bother with an array, just going for one with some work to mount it more effectively. There’s a pic below. It was well below 1.5 SWR at 144.1 and around 1.7 at 146.5.
2m quadruple quad at Mt Torbreck
I had thought of trying a longer pole but I would need to use stronger materials. Another idea is to mount it on a squid pole. I’ll think about this for next year, but this will be asking a lot more of the squid pole than a wire inverted V, end fed or a vertical on HF. Why a quadruple quad? Because it is roughly equivalent to a 15 element yagi, especially if I can get it off the ground a bit more.
Finally it was the 70cm quad-quad array. Here’s the pic:
Array of 70cm quadruple quads
One of the quads didn’t work so well, and time was running short, so I simply used the other one. Their feedpoint impedance is reported low at about 25 ohms. I’ll need to look into this some more, but I wanted to get operating at around 1:30 to 1:45pm so off I went.
It started lightly raining about 12pm, so I was a little reluctant to keep the MiniVNAPRO out in the elements. A few mad dashes and doing some analysis on the computer. My plan with the computer was to run it on the three 2.2Ah LiPOs directly until they were flat and then run it on the main supply for an hour. I could then run the computer on its own batteries for the rest of the time without them running out by the end. This worked well, but the 2.2Ah LiPOs gave me more time than expected. Nice to get more than you expect! When the LiPO monitors were reporting individual cells on the 2.2Ah batteries down to 3.55V, I pulled the computer out.
The whole 6 hours of operating was quite fast and furious. Most of the action was on phone, but VK3ER had a digital setup, at least on 6 and 2. They also had CW on 6/20/70 so there was some good triple dipping. I used Fldigi for PSK, and was more comfortable using it in the end in my one man tent lying on my side trying to type on a computer with the pouring rain outside than what I was in the middle.
I was also glad I brought the headphones, because the rain was very loud in that small tent. During the worst periods, I would mainly use the vertical antennas, which the main gun was the 2m colinear. The little whip at the end of the LMR400 cable on 70 was just no match for the 2m colinear. I need to get that 70cm colinear going for next year, these babies are just too good to ignore. The colinear being omnidirectional on the horizontal plane was good during the pouring rain because I did not need to get out of the tent to adjust anything. Same goes for the 6m turnstile (although it’s not a gain antenna). Gain on 6m might be a little hard to do given it needs to fit in a backpack along with everything else.
There was a 2 hour sunny period during the middle of the contest. This allowed me to get a bit more relaxed and I made more use of the quadruple quads. Towards the end it was raining again, but I really wanted some nice juicy contacts north into VK2, and my 2m q-quad was able to get them.
As for power, I already mentioned that the 2.2Ah LiPOs powered the computer well. I ended up not even using half of the 5Ah LiPOs, the first set of 6 were only 80% used at the end, with cell voltages around 3.75V. The “knee” on these is at 3.65V where the voltages start to fall away more quickly. I was hammering away with FM at 50 watts on 2m, but the LiPOs and the 12V regulator powering everything were stone cold. Not even lukewarm. This was a contrast to last year because my old 100 array of 18650 cells could not handle it. The LiPOs are just so much better for this usage.
Come 7:30pm it was finish time. I ended up not even turning on the HT’s. I barely used the FT-817, which is a major change from last year, where because of power constraints, I made most FM contacts on the HTs, and used the FT-817 for a fair amount of the rest. This year, the FT-897 was used for every scoring QSO. Did I mention that half of my big LiPO’s were not even touched? 🙂 I just had to make sure that at least 4 QSOs were at 5 watts so I could keep my QRP SOTA activator’s endorsement intact.
So contest finished, and it was time to go home. Too much stuff there to just leave it – although the thought did cross my mind as to what would happen if I just walked down the mountain with all that stuff still up there! It was raining again and it took about an hour to pull down all the antennas. With all the wet conditions, I needed to be careful getting the fragile computer back down the mountain, so I thought I’ll go easy on the weight on the first trip, but still enough to hopefully not have a tonne of weight on the second. One thing I’ll need to make sure of next time is to split up some of the LMR400 cable on the trips because this stuff is heavy.
I left on the first trip down at 8:30, left the car to go back up at 9:20, packed up the tent and did my final checks to make sure nothing was being left and departed Mt Torbreck at 10:20pm for the last time. I arrived at the car at 11:15. It was slow the last time with the heavy pack and the slippy wet conditions on the way down. At least it had stopped raining. I was very tired for the drive home and needed a 15 min powernap in Healesville to keep things safe. My wife thinks arriving home at 2:30am is crazy but it was a very good day with 92 contacts and over 1440 JMFD points.
Regards, 73, Wayne VK3WAM