Next AREG Meeting: Club Remote SDR Project – HOWTO Night

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AREG has long been seeking a location to establish a remote SDR receive site as a way of allowing members to escape the ever increasing levels of RF interference one sees in suburbia. Finally, the beginnings of this project are taking shape, with a trial system now in place at a location ~100km north of Adelaide.

This meeting will introduce the KiwiSDR system, and show people what was installed , as well as how to use it. We will also show the next steps with the antenna system and talk about ways of using the SDR system in your every day activities. We will also talk about the wider worldwide SDR network and how you can find your way around it.

(It should be noted that the system itself is being restricted to members only at this time due to the temporary nature of the trial site and internet feed).

The meeting will be held on Friday June 21st at the Fulham Community Centre, 1 Phelps Court, Fulham. The doors will open at 7.15pm with the meeting to start promptly at 7.45pm The presentation will commence immediately after a short business meeting.

Members and non members alike are both welcome at club meetings. If you would like to know more, why not come along and introduce yourself!

Automatic Radiosonde Reception – AREG Style!

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Thanks to Mark VK5QI, AREG is pleased to announce a new service has been added to the VK5RWN Repeater site. Mark has been developing a RadioSonde automated receive system which allows all of the Bureau of Meteorology weather balloon data to be collected and be made available on the internet. The data is available via the SondeHub instance of the HabHub High Altitude Balloon Habitat platform. You can access it here:

What can you see? Where all the active weather balloons are right now!

If you’re located in South Australia and are considering going out to recover a sonde, or have recovered one, please use the Facebook Group or the mailing list to announce your intentions! This helps avoid disappointment if others are intending to recover the same sonde.

Want to learn more? Read on…..

For quite a while now I’ve been interested in tracking and recovering radiosondes. These are meteorological instruments regularly launched by weather balloon from many locations around the world. Here in South Australia the Bureau of Meteorology launches them from Adelaide Airport twice daily (2315 and 1115Z), along with a few other locations around the state.

A Vaisala RS41 radiosonde found with the help of the radiosonde_auto_rx tracking network!

Radiosondes transmit in the 400-403 MHz band (usually on either 400.5/401.5/402.5 MHz), and there is a range of software, both closed and open source available to decode their telemetry. Not being entirely happy with the existing offerings, I started work on my own software, which became radiosonde_auto_rx (or ‘auto_rx’ for short).

auto_rx runs on a Raspberry Pi (or any other Linux machine) and automatically scans for and decodes radiosonde signals. Telemetry is uploaded to APRS-IS and the Habhub tracker for mapping purposes, and can also be viewed locally via a web interface. Most of the common radiosonde models are supported, including the Vaisala RS41 which is launched here in Adelaide. There are currently 147 auto_rx stations in operation worldwide (16 here in VK5), and so far (as of 2019-05-25 10Z) 19415 individual radiosondes have been logged.

So why do I bother doing this? Many radiosondes are (in part..) highly recyclable! The Vaisala RS41 contains a good quality GPS receiver, a micro-controller, and a radio transmitter – perfect for re-programming for use as a high-altitude balloon payload, as we have been doing on many recent Project Horus flights. In fact, the RS41 is the ‘reference platform’ for the new high-performance balloon telemetry system developed by David Rowe and I.

Chasing and recovering radiosondes is also great practice for Project Horus launches, with a few of the new Horus regulars starting out tracking radiosondes, and many others around VK5 regularly out chasing the BOM’s radiosonde launches. We use the same mapping software for both radiosonde and Horus chases.

To help improve tracking coverage, I proposed to install an auto_rx receiver station at one of AREG’s premier repeater sites, overlooking the Adelaide plains. Thanks to the generosity of AREG members in approving this proposal, the receiver was installed over the easter break. A big thanks to Ben VK5BB for assistance in fabricating an antenna bracket, and helping with the installation!

Hardware Details

The auto_rx receiver station installed in a rack at the site.

The auto_rx receiver hardware consists of a Raspberry Pi 3, with two RTLSDR v3 dongles attached, allowing simultaneous reception of 2 sondes. The incoming RF from the antenna is filtered through an interdigital filter (passband 400-403 MHz, stop-band attenuation > 90 dB) before being going through a preamplifier and splitter to the two dongles. The estimated system noise figure is about 5dB, mostly from the insertion loss of the filter. Given this is a very RF-noisy site (co-located DSTAR repeaters, and many commercial services on a tower a few hundred metres away), the higher noise figure is an acceptable tradeoff – without the filter the receivers would immediately overload!

All the equipment is mounted within a 2RU rack-mount chassis, with all power and network inputs heavily filtered to avoid coupling in unwanted RF. The total power draw of the unit is ~10W.

View from the antenna!

The antenna is an AEA co-linear (kindly donated to the project by Ivan VK5HS) mounted to the side of the repeater hut. Being ~450m above sea level, the antenna has direct line-of-sight to the Adelaide airport, and essentially anywhere to the west of Adelaide.

Receiver Performance

Receiving a radiosonde on the ground at Adelaide Airport

With such excellent line-of-sight, the station regularly receives signals from the Adelaide Airport radiosondes before they launch, and often even during the ground-test and calibration activities performed on the radiosonde within the Bureau of Meteorology building at the airport.

Also often visible are radiosonde launches from the Ceduna and Woomera receiving stations, which typically rise above the horizon when they reach ~10km altitude. Coverage to the east is not quite as good, being blocked by the Adelaide Hills, however radiosondes are regularly tracked down to ~1 degree elevation.

Would you like to know more?

  • More information on the radiosonde reception software is available on github at https://github.com/projecthorus/radiosonde_auto_rx .
  • A conference presentation delivered by myself and Michael Wheeler (VK3FUR) where we discuss the re-use of the Vaisala RS41 radiosondes is also available (see below)
  • You can track radiosondes launched from Adelaide Airport (and many other launch sites around the globe!) by visiting the Habitat Tracker at this link.

Thanks again to all those who helped make this possible!

73 Mark VK5QI

 

Next Meeting: Friday 10th May – Member Lightning Talks

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The next meeting of the Amateur Radio Experimenter’s Group will be held (yet again) one week early on Friday May 10th. This time it is a result of the Federal Election which has cancelled our hall booking for our normal night of May 17th. The doors will open at 7.15pm with the business meeting commencing at 7.45pm. The presentations for the evening will begin by 8.00pm. The event will be followed by coffee and cake!

AREG Lightning Talks

Photo by Mark VK5QI of Lightning over Adelaide 24th October 2014

This months meeting is a return to one of our favourite formats, the member lightning talk. While the talks are not about “lightning”, members are invited to give a lightning fast 5 minute introductory presentation on their latest experiment or project. Our time keeper Mark will keep things moving ensuring a lively and diverse range of topics can be covered over the 30-40 minutes of the presentations.

Members who would like to make a presentation should announce it on the club mailing list beforehand so we can plan the program order accordingly, although “drop ins” on the night will also be welcome. Projector slides if you want to show something should be sent to Grant, VK5GR on email prior to the event.

Afterwards, members of the audience will have the opportunity to get up close and personal with the presenters and talk to them in more detail about their projects and experiments. In this way we hope to promote sharing of what experiments the members are undertaking at this very moment.

Visitors are always welcome!

AREG is very happy to welcome visitors to our club meetings, so come along and find out what the membership of AREG is experimenting with!

The club meets at the Fulham Community Centre, Phelps Court, Fulham.

We hope to see you there!

FreeDV QSO Party a success despite trying conditions

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This weekend just gone marked the second FreeDV QSO party (the first was 3 years ago). The aim of the event was to encourage people to come and take a look at FreeDV, load up the software and give it a try. It had the added benefit of stimulating a lot of FreeDV activity on the bands as well which was great to see.

Reports have come in from 4 continents of local activity in those regions. So far, however,  there havent been any reports of any inter-continental contacts with VK5ARG or other VK stations. Conditions were certainly difficult but at least regional activty was spawned across the globe! The key thing is that there are now more stations active and capable of FreeDV. It will only be a matter of time before we start seeing regular inter-continental FreeDV QSOs taking place!

Activity Around Australia

Australian activity was predominantly on the 40m band centered around 7177-7185kHz. At times on Saturday afternoon there were 5-6 stations on air simultaneously with lots of calls being swapped back and forth around the continent. Much of the activity used the FreeDV700D mode although at times FreeDV appeared more reliable. Selective fading was identified as a particular challenge during some of these QSOs (see above) even within 1kHz of bandwidth.

Stations were logged between VK1/2/3/4/5/6 either on 40m or 20m, VK FreeDV 20m activity was predominantly on 14130-14135kHz. More on this later.

From the VK5ARG logs it was noted that probably 1 in 2 stations contact was made with were trying FreeDV for the very first time. That alone made the event a roaring success in our eyes.

QSO Party report from the UK/Europe.

Mike G4ABP reported that European propagation has been poor in recent days, as was the case on the day of the QSO party. Consequently, he was not expecting to hear anyone from outside Europe.

Participation from Europe was not great, with about 10 European stations appearing on FreeDV QSO Finder, only one of which I knew previously. Mike monitored QSO Finder for about 16 hours, and had never seen it so busy, (particularly with US stations). Attempts were made via QSO finder to set up European QSO’s, but stations were out of range due to poor propagation. 

Activity around North America

Walter K5WH reports that with all the publicity of the event coming up there has been a great explosion of stations giving it a try, and we have worked with several dozens of stations helping them configure and test out their stations prior to the event.

“The FreeDV QSO finder has been really active with a great deal of interest in trying out the mode. There were a great deal of stations that were busy on the normal US frequency of 14.236 making contacts all day, even if they were not in the contest itself. So from my prospective, even though we did not have much success in the US with the contest, all of the enhanced activity on FreeDV leading up to the contest has really created some great attention and hopefully a lot of new stations to help us keep this mode very active. For that reason alone I would have to say this was an outstanding success for its 1st event.”

Mel K0PFX reported “Yes, the FreeDV QSO party created a lot of interest here in the US as reflected in the number of stations found on the QSO Finder throughout the time period.  I did work a few stations who were not on the Finder indicating there were more around and I am sure, many were just “listening” to see what they could decode.  W4BCX,

Ray in Florida I heard working a number of stations attributing to his great location and excellent signal.  From the NE US, WF1C was worked and heard calling other stations.   And, of course Gerry, N4DigitaVoice was in there working them on his Flex 5k which is an excellent radio for this mode.

From Mexico, XE2JC was there and I was able to decode him but never worked him.  However, I believe Ray worked him. 

Despite the low sun spot activity and the Florida QSO SSB party QRM, we all had fun in the party and good to see all the activity it stirred up.  Thanks to Grant, VK5GR and others for the organizing the event.  I look forward to the next one.”

Activity in South America

Not to be out done, we also had a lot of interest from South America with activity by a number of Argentinian stations. Logs have been received from Alex LW4DFA who worked a number of stations on 20 and 40m as well as Jose LU5DKI who worked ~8 stations again across 20 and 40m as well as several on 80m!

Thanks guys for your interest before and during the event. Please encourage those you worked to also submit logs!

Its not too late!

Now is the time, if you haven’t already done so already, to submit your FreeDV QSO party logs! We would love to see who was active and how they got on! You can send your logs to:

Log Submission:

You MUST submit your ADIF formatted log via email within 7 days after the event to:

FreeDV.QSOParty (at) areg.org.au

Finally, a huge thanks to David VK5DGR for creating this fascinating mode and to all of the operators that decided to give it a go this year during the FreeDV QSO party.

David VK5DGR – Creator of FreeDV

AREG April Meeting THIS FRIDAY – Introducing FreeDV!

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Thanks to Easter this year, the AREG meeting is being held 1 week early on Friday April 12th, starting at 7.45pm. Doors open at 7.15pm.

This months presentation is by David VK5DGR, who will introduce FreeDV, talking about it’s capabilities and development as well as how you can try it yourself.

David will also discuss the latest developments in FreeDV and will hopefully give us a sneak peak of what is coming just around the corner.

We will also discuss the up-coming FreeDV QSO Party, the rules and what you need to do to be able to take part! The FreeDV QSO party is being held over the weekend of April 27th and 28th.

At the club business meeting we will also be discussing a working bee to recover the original attempted remote SDR site over the Easter/Anzac day break as well as the pending River Paddling Marathon 200 community event which is supported by AREG each year over the June long weekend.

So why dont you come along and find out what we are up to today in the Amateur Radio Experimenters Group Inc. The clubrooms are located at the Fulham Community Centre, Phelps Court, Fulham.

We hope to see you there!

VK5RWN D-Star system upgraded to allow linking to XRF & DCS reflectors

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For those who came in late………….

The VK5RWN D-Star gateway and repeater system was upgraded in May June 2018 with a new computer running 64 bit CentOS 7 and the new Icom G3 gateway software.

Between then and March 2019, the system has proven to be relatively stable with only a couple of minor hiccups where the computer has shut itself down? We believe this may have been due to the CPU over heating or something similar? This is still being addressed.

VK5RWN is a D-Star gateway system, registered on the US Root Trust database and primarily runs an application called Dplus which manages the linking and routing functions on the D-Star Internet network between other D-Star gateways/repeaters/reflectors.

As such, users are able to connect to other repeater/gateways and Dplus based Reflectors anywhere around the World, or even to other registered D-Star users via Call Sign Routing, a bit like a “private” call in the commercial PMR world.

In principle, within the D-Star world, there are two D-Star Internet networks, the Dplus/US Root Trust network and the ircDDB D-Star open network. Again in principle, the two are mutually exclusive networks and are not interconnected.

This creates an issue where D-Star users accessing the “D-Star World” via a Dplus connection cannot connect to other gateways and reflectors that are using the ircDDB network and vice versa and are therefore limited to accessing the Dplus REFxxxX reflectors. (eg REF023C)

Hams being hams, they just cannot help themselves, the challenge was there and so software was developed that when installed on the Dplus Icom based gateways, allowed interconnectivity into the ircDDB networks and allow access to the XRFxxxX and DCSxxxX based reflectors. One version of this software is called “g2_link” and is designed to be added to existing Icom based D-Star gateway systems on the US Root Trust network.

Early March 2019, Michael VK5ZEA, who is custodian of the VK5REX D-Star system on lower Eyre Peninsular, advised me that he has rebuilt the VK5REX system and had successfully installed the “g2_link” software with the help of Terry, KA8SCP. Michael also passed on Terry’s contact details, whereupon I made contact and asked Terry if he would mind assisting with installing the “g2_link” software on VK5RWN.

Terry most kindly agreed to assist and arrangements were made that allowed Terry to install the software and set up the necessary configuration and interlocks so that both the Dplus and the ‘g2_link’ accessed networks could be worked via VK5RWN.

This now allows for D-Star users to access VK5RWN via a RF input from their D-Star radios and they may now access both the REFxxxX, XRFxxxX and DCSxxxX reflectors and gateways.

A bonus as part of this new configuration, new Dashboards were part of the set-up and now show the connection status and ‘Last Heard’ lists of the VK5RWN system.

Have a look at

For D-star users, please read the instructions at the bottom of the XRF/DCS Dashboard. This is important as there are two distinctly different “linking” or “unlinking” commands to connect or disconnect to and from REF reflectors and the XRF/DCS reflectors. This is so that the system can differentiate between a request via Dplus or the ‘g2_link’ and allow the respective link request to be actioned or disconnected.

It is recommended for D-Star users to use VK5RWN Port C, the two metre port, for connecting to any of the reflectors as VK5RWN Port B, the 70cm port, is normally permanently connected to the REF023C Australasian/Oceania reflector. Before connecting to a reflector, please ensure that the Port is not currently connected to anywhere else. The VK5RWN B 70cm port may be used, but it must be disconnected from REF023C first.

I wish to thank Michael VK5ZEA for his support and advice and especially Terry, KA8SCP, for his help, patience and advice where I needed to do some house keeping that allows VK5RWN to function as a flexible D-Star gateway, allowing D-Star users access to the big wide world via both the Dplus and ircDDB D-Star networks.

73 Ben VK5BB

FreeDV HF Digital Voice Mode: Global QSO Party April 27/28th

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The Amateur Radio Experimenters Group is proud to announce a new event on the Amateur Radio Calendar. The FreeDV HF Digital Voice QSO Party!

The aim is to encourage as many Radio Amateurs as possible to learn about FreeDV and encourage as many FreeDV signals to be on the air as possible to help spread the word about this new mode.

If you can use WSJT-X for FT8 or any other digital modes software then, with the addition of Headphones and a microphone on your PC, you can switch to digital voice transmission in an instant! Its that easy! So why not give it a try? This is a great way to experiment with something new from the comfort of your own armchair. All it takes is a little bit of time to download, install and setup the software – nothing more!

What to know more? The QSO party rules are below, plus details of where to get FreeDV are included later in this bulletin. Read on!

The Rules

When: April 27th 0300z to April 28th 0300z 2019

Where: All HF Bands from 160m – 10m (excluding the WARC bands)

How: Work as many stations as possible using the FreeDV 700D or FreeDV 1600 modes in 24 hours. You can rework the same station once every 3 hours per band.

Centre Frequencies: 1870kHz, 3630kHz, 7180kHz, 14130kHz, 21180kHz, 28330kHz (chosen in accordance with IARU Bandplans)

Exchange: Signal Strength + Serial Number starting at 001

Points: Stations participating can earn points per QSO

  • 1 point per contact within a continent
  • 5 points per contact between continents
  • 50 points per contact with VK5ARG

(AREG’s club station is planned to be manned for the 24hrs looking particularly for inter-continental DX on 40/20 and 15m)

Multipliers:

  • 1 per call area in VK/VE/JA/ZL per band +
  • 1 per DXCC entity per band +
  • 1 per inter-continental contact

Final Score:

  • Sum all points x sum all multipliers

You can work a station once per band.

Stations earning 50 points or more will be entitled to an emailed PDF certificate indicating their successful participation in this inaugural event!

Categories:

There is one entry per station callsign only.

Log Submission:

You MUST submit your ADIF formatted log via email within 7 days after the event to:

FreeDV.QSOParty (at) areg.org.au

What is FreeDV?

FreeDV is an open source digital voice transmission mode developed for HF Amateur Radio by David VK5DGR. It is founded on open source principles with the Codec2 specification and code fully available to the Amateur Radio community at no charge.

The latest development, FreeDV 700D mode has performance equivalent or better than SSB on HF – a remarkable achievement in only 700 bps!

Why FreeDV?

FreeDV 700D outperforms SSB at low SNRs – you can get an easy copy of 700D when SSB is unusable.

Amateur Radio is transitioning from analog to digital, much as it transitioned from AM to SSB in the 1950’s and 1960’s. How would you feel if one or two companies owned the patents for SSB, then forced you to use their technology, made it illegal to experiment with or even understand the technology, and insisted you stay locked to it for the next 100 years? That’s exactly what washappening with digital voice. But now, hams are in control of their technology again!

FreeDV is unique as it uses 100% Open Source Software, including the speech codec. No secrets, nothing proprietary! FreeDV represents a path for 21st century Amateur Radio where Hams are free to experiment and innovate, rather than a future locked into a single manufacturers closed technology.

FreeDV can be used on multiple platforms including Windows, Mac and Linux systems.

Where can I get FreeDV?

FreeDV software and more information is available from the FreeDV Website!

FreeDV.org

Supporting Events?

If you live in Adelaide, South Australia, there are two events planned prior to the QSO party to help you get FreeDV operational. AREG will be holding a “Tech Night” on April 5th at the clubrooms in the Fulham Community Centre starting 7.00pm. In addition, David VK5DGR (FreeDV’s creator) will be our guest presenter at the April AREG meeting on Friday the 12th. Doors open at 7.15pm for that event.

AREG is also looking to re-launch the FreeDV WIA News Broadcast. New times and frequencies will be announced soon! This provides a perfect opportunity to experiment with FreeDV reception while the broadcast is running for 30 minutes, plus you can participate in the callbacks afterwards.

At the April meeting a new version of FreeDV is also going to be released that promises significantly improved audio fidelity over the communications grade 700D and 1600 modes. Why not put it in your diary and come along – visitors are most welcome!

Want to know more?

Who can I Talk To?

Login to the K7VE FreeDV QSO Finder to find other Hams using FreeDV.

Support

Please post your questions to the Digital Voice Google group

Developers please subscribe to the Codec 2 Mailing List.

IRC Chat

For casual chat there is a #freedv IRC channel on freenode.net

We hope to see you on FreeDV!

Next AREG Meeting March 8th (early) – 6m Moonbounce

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The moon at moon set (4am) with our 6m EME antenna – Photo by Scott VK5TST

Several weeks ago, members of AREG headed out into the country side to try an experiment that many had wanted to do for many years – bounce a signal off the moon. With the help of Peter VK5PJ who has the necessary high power permits, we were able to achieve just that!

The team involved will take people through the events of that weekend and share what we learned about EME procedures, RadHaz management, JT65A and what it takes to send a radio signal over a half a million km journey to the moon and back.

Meeting Date and Time

NOTE This month’s AREG meeting is occurring one week early on the 2nd Friday of the month, so as to avoid clashing with the John Moyle Memorial Field Day Contest the following weekend. The hall will open at 7.15pm and the meeting will commence at 7.45pm sharp with a short AREG business meeting. The guest presenters will start by ~8pm. The presentation will be followed by coffee and cake and an opportunity to discuss EME with those who were there.

AREG meets at the Fulham Community Centre, Phelps Court, Fulham (formerly known as the Reedbeds Community Centre).

Visitors are most welcome!