VK5RWN D-Star repeater site antenna tower replacement.

Back in mid August 2017, the tower supporting the antennas for the VK5RWN D-Star repeater system was damaged during the big blow that accompanied the storms. The tower, which was a section of a Hills Telemast bolted at the roof line of the communications hut, has been in service for about 27 years and was in good order. It appears that the wind loading had been exceeded during the August storms and the tower was bent just above the roof line of the building and the top section with the antennas was approximately 30 degrees off the vertical.

Well, no option, it had to be replaced!

The working bee at the VK5RWN site was scheduled for Tuesday 19 December 2017.

Ben VK5BB was at the site around 0845 hrs local time and the other members of the work crew arrived shortly afterwards.

Apart from initial preparations, and the OH&S site survey, the first job of the day was to erect the scaffolding, on the roof of the building! Gave us very easy access to all antennas for disassembly. The scaffolding was also used for the reassembly, thereby minimising the need to actually climb the tower, though Colin VK5ACE later did, to re-mount the 2m antenna at the top.

From there the antenna equipment was easily removed and the bent tower was cut off just above the bend in the tower (just above the roof line) and the tower easily removed. The coaxes were laid out to one side so as not to be damaged and ready for re-installation.

Whilst the old tower was being removed, other members bolted the new tower sections together ready for erecting. The new tower is two sections of Hills 330mm Butt Section mast, with additional plates fitted at the join of the two sections to provide some additional strength at the join.

The top end of the new tower was lifted (man-handled with ropes) above the adjacent hut and then the base lifted into position near where it was to be mounted. Using the ropes, the tower was then pulled upright, across the gap between the two buildings to its mounting position, loosely bolted in place whilst we marked out where the base bolts were to go, drilled and fitted the Dyna bolts and the tower was firmly bolted in place. Actually went in place quite well with a minimum of jiggling etc!

Lunch time! (about 1300 hrs local)

After lunch, the antenna cross arm and antennas were refitted, thanks to Colin VK5ACE, the main climber/rigger for the day. As the Wi-Fi dishes were refitted, the day started to get a bit blowy but the dishes were pointed approximately in the right directions. The 2m 7 element Yagi for the Broadcast Source transmitter was re-installed as a 3 element Yagi and pointed at Crafers. All coaxes were resealed, dressed and cable tied to the tower.

All antennas are back in their old positions, determined by the lengths of the various coax feeds. The tower, now 9m high, carries a 2m, a 70cm and a 23cm vertical “white stick” collinears, two 200mm Wi-Fi dishes and a 3 element 2m vertical Yagi.

Job done!

All equipment was turned on again and the various systems tested, we even had the Internet back on at the site, so we did get the dish right, either that or it has strong side lobes. (The Internet connection was previously still working even though the dish was pointed at the sky? A relay from the ISS??)

Clean up, and we were gone by 1700 hrs local.

The D-Star operations were checked at the site and later again from Ben’s QTH and all was good, including remote access to both the D-Star and the Broadcast computers.

Crew on site;

  • Trevor, VK5ATQ, roustabout and also supplied the scaffolding, (NERC member)
  • Rod, VK5ZRK, roustabout, (NERC member)
  • David, VK5MDF, roustabout, (NERC member)
  • Colin, VK5ACE, rigger, (AREG member)
  • Jeff, VK5IU, “supervisor” and roustabout, (AREG member)
  • Ben, VK5BB, project manager, 2nd climber/rigger, (AREG member)

Many thanks to the crew who helped during the day and especially Olga VK5FOLG, as she supplied a fresh cut lunch for all and delivered on site about 10 minutes before the lunch break.

Reports from the D-STAR users have reported a significant improvement of signal strengths at Balaclava and Mt Barker on 2m and from Hallet Cove on 70cm, so all appears to be good again.

Next task for the VK5RWN D-STAR system is the upgrade of the computer to a new 64bit system running CentOS 7 64 bit and the new G3 gateway software. This is scheduled for early in 2018.

Willunga High School Launch – Success!

This slideshow requires JavaScript.

On the 7th of December 2017, members of Project Horus participated in the successful launch of the Willunga High School’s 2017 balloon launch. This year Willunga High School was participating in a ‘Balloons Without Borders’ exchange program with the United States ‘Near Space Systems’ – Near-Space Systems would launch Willunga High School’s payload, and the US payload would be launched here in Australia. The US payload contained cameras and various atmospheric sensors.

NearSys BalloonSat Payload

The chase team consisted of Mark Jessop VK5QI, and Matthew Scutter, the developer of SkySight.io, a weather prediction service that Project Horus has made use of many times for launch-day weather predictions. This was Matthew’s first balloon chase, and as is custom, he got thrown straight into the deep end acting as navigator and operator of the chase car software.
Mark describes the launch day as follows:
We launched right ahead of a cold front that was moving in, which threatened to make the flight challenging. During my drive to the launch site I encountered large areas of showers, however the Willunga area stayed clear for quite a while. 
The winds did start to pick up during launch preparations, but were not strong enough to make the launch difficult. We ended up with a total payload mass (combined across the 2x telemetry payloads, 1x Wenet imagery payload, and the BalloonSat) of approximately 1300g.
The flight proceeded pretty much as planned, with an average ascent rate of 5.2m/s. The payload’s ground speed was observed to reach 200kph at some points during the flight. The balloon was cut away at just under the predicted burst altitude of 30km, in an attempt to bring the landing site closer towards the Dukes Highway, a major highway running through the region. The maximum altitude was 29949m. 
The descent rate was faster than expected, around 10m/s on landing. This turned out to be due to one of the payloads tangling with the parachute, causing it to not open completely. This brought the landing location a bit further away from the highway, and made the descent portion of the flight too fast for the our lonesome chase team to get to the landing site in time to watch the landing. 
We arrived about 20 minutes after landing to find the payload in a large, recently cropped field, about 200m from a road. Shortly after we departed, the cold front arrived and the rain started – we had recovered just in time!
All the payloads were recovered in good condition, in spite of the faster-than-expected landing. Constructing the payloads from lightweight expanded polystyrene does have its advantages!
The live Wenet imagery didn’t perform too well, mainly due to lack of receivers. I had a receiver running in my chase car, and Graham VK5EU did a great job of receiving from home.
Thanks also go to VK5HS, VK5APR, and VK5NEX for decoding the RTTY telemetry throughout the flight!
 The flight profile and chase vehicle tracks can be seen here.
The flight statistics are:
MetricResult
Flight Designation:WHS-December 17
Launch Date:07/12/2017 00:11:45 UTC
Landing Date:07/12/2017 02:08:09 UTC (Approx)
Flight Duration:1 Hour 57 Minutes
Launch Site:-35.262946 138.555586
Landing Site:-35.755356 139.736493
Distance Traveled:124.8 km
Maximum Altitude:29,904 m
Thanks to everyone involved in yet another high altitude balloon flight!

Adelaide Rally using VK5RSA / VK5RSB Repeaters

WICEN has approached AREG to help with their communications nets during the Adelaide Rally this year on the 7th,8th and 9th of December. For the most part, WICEN will use the VK5RHO Ansteys 2-meter repeater (146.850) but for 2 other stages they are requesting to use the VK5RSA 70cm repeater (438.025). AREG is very supportive of this type of use of the club repeater assets and so naturally has agreed.

The times and stages are:

  • Thursday – Old Norton Summit (approx 2:30pm till 5:30pm)
  • Saturday – Norton Summit (approx 12:30am till 5:00pm)

WICEN may also require access to Summertown VK5RSB (439.900) as a possible backup for a Saturday afternoon stage.

WICEN’s role is backup communications and radio traffic should be minimal.

Amateurs who hear the rally traffic on these repeaters are asked to give WICEN priority access during the event. Your cooperation is greatly appreciated!

High Altitude Ballooning: Willunga HS Supported by Project Horus

The Willunga High School is planning to launch a high altitude balloon, planned for this Thursday, the 7th of December. Launch time will be around 10:30 AM ACST. This flight is being carried out by the teachers at Willunga High School.

While not a direct Project Horus Flight, it is being supported by the Project Horus team with tracking payloads, recovery services and telemetry feeds. Amateur Radio operators from across the state are invited to contribute to the telemetry collection activities which will use the same Internet resources as Project Horus does.

Flight Predictions

The predictions are a bit variable – there is a weather change coming through Thursday & Friday which are throwing things out. As of Sunday 3rd December’s model the balloon is landing somewhere near Ki-Ki, but this is expected to change. If the predictions change markedly, the launch may be rescheduled to Friday.

Target burst altitude is 30km, but depending on predictions the flight may be cut-down early to ensure a safe recovery.

The radio payloads on this launch are currently planned to be:

  • RTTY Telemetry – 434.650 MHz
  • Cutdown / Mission Control payload – 431.650 MHz
  • Wenet Imagery on 441.200 MHz

As usual, assistance with tracking is greatly appreciated.
Information on tracking the RTTY payload is available here: https://ukhas.org.uk/guides:tracking_guide

Live tracking of the flight will be available on the HabHub Tracker: https://tracker.habhub.org/#!mc=-34.8,139.0&mz=9

Finally, if we can get enough packets down from the Wenet payload, live imagery will appear here: http://ssdv.habhub.org/VK5ARG

More news as we get closer to the day!