Project Horus: D-ATV Receiving – Test Transmissions this weekend – HOWTO Get Involved!

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The D-ATV test flight of Project Horus is getting closer. This weekend Mark VK5QI will be up on the hills face overlooking Adelaide and will run the balloon transmitter from the ground to give stations a chance to configure their receiving equipment before the main event on Sunday March 7th.

UPDATE: This event has now concluded. Eight stations were able to get setup to receive the DVB-S signals. We are still on track to launch this coming weekend, with the planned launch date still being Sunday the 7th of March at 10AM. If weather conditions do not permit a launch on this date, Monday the 8th of March (a public holiday in VK5) is the first backup date, with a launch the following weekend being the second backup. The launch site is still TBD (either Auburn, Two Wells, or Mt Barker).

Mark will be available live on the air for people to test their receiving systems at the following times and places this coming weekend:

– SATURDAY 27th Feb

  •    – ~11AM Start. ~1 hr duration.
  •    – TX Location: VK5SFA QTH (Woodforde, SA)
  •    – Coordination: VK5RSA 70cm

– SUNDAY 28th Feb

  •   – ~11AM start. ~1 hr duration.
  •   – TX Location: Para Power Station (Blacktop Hill Road)
  •   – Coordination: VK5RSA 70cm.

The setup guide is available here: docs.google.com/D-ATV_Setup_Guide

NOTE: There may be an update to SDRangel before the launch. The new version will display signal MER (Modulation Error Rate) information, but has not been released yet.

If you missed the AREG presentation on what was required to to receive the balloon, the video is available via the HamRadio DX Youtube channel (Thanks Hayden!)

Project Horus Balloon Project: Digital ATV DVB-T Terrestrial Testing – Success!

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Today Mark VK5QI took the Balloon ATV transmitter out for a terrestrial test. He carried out line-of-sight testing of the DVB-S payload from BlackTop Hill to the AREG remote site near Tarlee – a distance of 54km!

First test – could he see the signal on the SDR up at the site (RTLSDR, Diamond X-50, no preamp)… yes!

Next, Mark dumped some samples with rtl_sdr, then transferred them back to his laptop. He processed them through leandvb – and got video!!! A bit of fading, but for an omni receiver with no preamp, this is a pretty damn good result!

… and here’s some of the raw video

The MER as reported by leandvb was around 8-11 dB, right on the edge of what is decodable. Still, with such a basic system, a good result!

Based on the path, it is estimated to give us a working range of about 150km from the balloon given a receiving station with 15dBi gain and a good low noise preamplifier.

Stay tuned for more information on how to receive and decode the Digital ATV signal and save the date – we hope to launch the transmitter into the stratosphere on Sunday March 7th. (We also plan on streaming the event on Youtube).

For those who missed it late last year here is a bit more information about the Balloon ATV payload and some minimum signal testing that was carried out.

Australian Facebook News Blackout: Subscribe to our Announce Mailing List instead!

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The ongoing dispute in the national media landscape between Facebook and the Federal Government has resulted in AREG no longer being able to directly re-post our own information, news and events from our Website.

So you dont miss out, why not consider joining our “AREG News Mailing List”?

Simply send an email to:
announce-subscribe@areg.org.au

 

AREG Fox Hunt Fridays – February Hunt Report

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The second of our monthly fox hunts for 2021 was held last Friday the 12th of February.

Four AREG members set out to hunt the foxes down and we were also joined by guest Brian, VK5TBC.

The usual two 144MHz foxes were deployed by Grant VK5GR as well as a bonus ultra low powered 25mW 433 MHz fox, made from a repurposed ex Bureau of Meteorology Radiosonde.

The first fox was hidden by the banks of the River Torrens in Lockleys. The second was hidden in a tree on the golfing greens just behind North Adelaide Railway Station.

The third 70cm fox was hidden roughly 400 meters from from where the first 144MHz fox was deployed.

Sigtrax is a great mobile app for plotting bearings/beam headings when when out hunting the fox.

The 144MHz fox hidden in a tree on the North Adelaide gold course

 

The next fox hunt is scheduled for the evening of Friday the 12th of March. This hunt may see us start from a new location of stay tuned for more info!

 

Reminder: AREG Meeting this Friday – D-ATV from a Balloon 30km up!

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This is a reminder that this Friday’s AREG meeting will be held at the Fulham Community Centre, Phelps Court, Fulham. Doors open at 7.15pm Central summer time with the presentation planned to start at 7.45pm.

Our guest speaker will be Mark VK5QI. He will introduce you to the new Digital ATV payload and what you need to be able to receive and decode it. More information on the presentation is available (here).

Members who can’t attend in person will be able to access the meeting via Zoom (a link will be sent on the members mailing list on Thursday). Non members will be able to watch the Youtube Livestream thanks to Hayden VK7HH and his HamRadio DX channel.

The times are:

  • 7.45pm ACDT (SA)
  • 8.15pm AEDT (NSW, ACT, VIC, TAS)
  • 7.15pm AEST (Queensland)
  • 6.45pm ACST (NT)
  • 6.15pm AWST (WA)
  • 0915Hrs UTC

We hope to see you there!

Adelaide CBD 70cm Repeater returns to service! (UPDATE)

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After several years off air and/or operating from a temporary site in the western suburbs, the Amateur Radio Experimenter’s Group is please to announce that we have been able to negotiate a new home for the club’s VK5RSA Adelaide CBD 70cm repeater!

AREG has entered into a sponsorship agreement with KernWi-Fi, who are supporting the club by facilitating access to one of the premier communications sites in the Adelaide CBD atop Westpac House. At 134m high, this site is on one of the highest buildings in the city! AREG wishes to express it’s sincere thanks to Phil Kern (VK5ZEY) for his support of the VK5RSA repeater. It has been a dream of the club to gain access to the site for nearly 20 years and it is great to see it finally come to fruition.

The repeater itself has been rebuilt by Paul VK5BX & Dean VK5HMV, and was installed by Dean VK5HMV and Shane VK5NRV over this past weekend. This was the culmination of 9 months of discussions and planning by the AREG Committee, members on the repeater sub-group and the KernWi-Fi team.

 

VK5RSA operates on

438.025MHz (-7MHz input)

with 91.5Hz  CTCSS

 

NOTE: The repeater input frequency was changed Monday night due to un-resolvable interference from the co-sited commercial operators. VK5RSA is now operating according to the new 70cm band plan, with a repeater receive frequency of 431.025MHz. This is a -7MHz offset instead of the old -5MHz offset that was in use previously.

But Wait – there’s more!

In addition to being installed atop one of the highest buildings in Adelaide, VK5RSA is now part of something much bigger. It has now joined the growing Central South Australian repeater network, which provides coverage over most of central SA.

The repeaters in the network are:

Location / AreaCallsignOutputInputCTCSS
Adelaide CBDVK5RSA438.025MHz-7MHz91.5Hz
Adelaide RegionVK5RAD439.925MHz-5MHz
Adelaide NEVK5RKW438.050MHz-7MHz
Lobethal / Adelaide HillsVK5RAH146.775MHz-600kHz
Mt Bevor / Murray BridgeVK5RMB146.875MHz-600kHz
Victor HarborVK5RVH147.100MHz-1.6MHz
WaikerieVK5RWR146.750MHz-600kHz91.5Hz

NOTE: With the network access comes a change in mind set for operators too. For all 6 repeaters to operate together, it is important for users to leave at least a 1 second gap after the repeater tails before transmitting. This will give sufficient time so that all of the transmitters and receivers can sequence correctly thus preventing one or more repeaters from being locked out.

The nominal best areas to access each repeater are shown here:

Strongest Serving Repeater Map (Note Victor Harbor not shown)

The coverage of the system is expected to be second to none in this part of the state. AREG hopes by making VK5RSA part of this network that it will help bring amateurs together on VHF/UHF and will drive new activity on these bands!

We look forward to hearing you on VK5RSA and the link network! Come and give it a go….

Next Meeting: 19th February: Live ATV from 30km+ altitude! How to get involved?

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Project Horus began in 2010 as the brain child of a group of radio Amateurs here in Adelaide. Now, 11 years later, one of the ideas that has been discussed many times within the group is finally going to be attempted. A flight is tentatively planned for Sunday March 7th that will carry aloft our first ever digital ATV transmitter.

Live ATV from 30km+ altitude!

Adelaide from 100,000ft – Horus 12

How can you get involved?

So that as many people as possible can participate or at least attempt to receive the ATV pictures, the next meeting of AREG on Friday February 19th will feature a presentation and Q&A session with Mark VK5QI. He will take you though everything you need to know about how to receive and decode the ATV signal.

What system are we using?

For the first launch, we are going to use the following transmitter settings:

  • Transmit Frequency: 445 MHz
  • Modulation: DVB-S, QPSK, r=½ FEC
  • Symbol Rate: 1Msps
  • Video Resolution: 704×400

This will produce fairly low quality video, but will give the best chance for the payload to be received. Once we understand what the achievable signal-to-noise ratio (SNR) is for a typical flight, the symbol rate (and image quality) can be increased on future launches.

Receiving DVB-S Signals – Hardware

The most ideal way to receive signals from this payload is with a dedicated DVB-S receiver like the Minitiouner Express ( https://www.datv-express.com/ ), however it’s also very possible to receive it with Software Defined Radio receiver setups, such as the ubiquitous RTLSDR devices. You will also need a 70cm antenna with some gain, and a low-noise pre-amplifier.

While some DVB-S set-top boxes may tune down to 445 MHz, the very low bit-rates that we will be transmitting from the payload will likely be incompatible with them.

Suggested Software-Defined Radio Receivers

There’s a huge range of SDRs available which are fit-for-purpose in this application, provided you put a low-noise-figure preamp in front of them – ideally one with band-pass filtering. Examples include:

Mark testing the ATV receive across the bench

More detailed instructions and information will be posted to our website in coming days. Stay tuned!

Meeting Details

The main meeting will be held at the clubrooms, 1 Phelps Court, Fulham at the Fulham Community Centre. Doors will open from 7.15pm (ACDT) with proceedings starting at 7.45pm (ACDT) (0915z). For those unable to attend in person, we will have online options available too!

vk7hh-hrdx
YouTube_(2015-2017)

The meeting on February 19th will also be live streamed on YouTube thanks again to Hayden VK7HH and his HamRadioDX Channel.

For members unable to attend in meeting hall in person, there will be a members only Zoom channel available as well.

Links to these will be posted closer to the date!

AREG Foxhunts: Reminder Next Adelaide hunt TOMORROW (Friday) 6.30pm

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The next of our monthly fox hunts is scheduled for Friday the 12th of February. Hunters are to meet from 6:15pm in the car park at Lockleys Oval – Rutland Ave, Lockleys. As usual, this event is open to all interested parties, be it members and non-members.

This hunt will again see us hunting at least one and possibly two 144 MHz hidden transmitters throughout the Adelaide metropolitan area. The frequency of the fox(es) will be broadcast on AREG’s VK5RSB Summertown 70cm repeater on 439.900 MHz a few minutes before 6:30pm with all invited to liaise and discuss their progress on the repeater throughout the night (91.5 MHz CTSS tone required on input).

We look forward to seeing you there.