Automatic Radiosonde Reception – AREG Style!

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

 

AREG IRLP & DSTAR Gateways Back in time for JOTA

 

After several months of disruptions due to lightning and HDD failures at both the VK5RSB IRLP node and the VK5RWN DSTAR Gateway AREG is pleased to announce that we have been able to restore both services in time for this weekend’s Jamboree on the Air for the Scouting and Guiding communities.


VK5RSB Internet Relay Linking Project Node #6214

The IRLP Node 6214 will be available for use by users supporting JOTA this weekend, 20, 21 October. The node can be accessed via the VK5RSB 70cm repeater on 439.900 (-5MHz) using a 91.5Hz CTCSS access tone.

In the support for JOTA, the prefix access code has been removed for this weekend, thus allowing free access to the node.

Therefore to access remote IRLP nodes,

  • dial in the 4 digit DTMF node address of the remote node.
  • to disconnect the IRLP connection, just dial “73” a the end of the QSO.

AREG wishes the JOTA teams and other users, to have fun with contacts via the IRLP Node 6214.


VK5RWN DSTAR Gateway Restored for the 2m/70cm repeaters

The VK5RWN D-Star repeater and gateway is also now fully functional after its computer rebuild. It’s new computer has been installed and the gateway configuration is now complete using the new ICOM G3 software.

Currently the configuration is;

  • Port C, the 2m port, is unlinked and available for general use or user linking to reflectors and gateways etc (147.0375 +600kHz)
  • Port B, the 70cm port, is permanently linked to Reflector REF023C and will output any activity on this reflector and will repeat local RF activity on the 70cm channel into the reflector network. (438.400 -5.4MHz)

NOTE: Port B may be disconnected from the link to REF023C with the unlink command, “^^^^^^^U” , (the ^ represents spaces)  then it may be connected by the user to another address.

VK5RWN activity is now being reported to various Dashboards,

D-Star network access seems to fully functional. Ben VK5BB reports that he has tested linking to several reflectors through the local gateway as well as connecting directly to VK5RWN via his JumboSpot hot spot successfully.

So, any members or DSTAR users in Adelaide who have an interest in D-Star, have D-star capable radios and are registered on the D-Star system, please give VK5RWN a try out and feedback will be appreciated please?

73 from Ben VK5BB

VK5RWN Internet Gateway Failure – Local Mode Only

Dateline: August 18th 2018 – The VK5RWN D-STAR gateway computer and therefore the D-STAR repeater networking is off line due to a failure of the current computer’s SSHD storage.

Both the 2m and 70cm D-STAR DV repeaters are still on and available for use providing local coverage as D-STAR DV repeaters, however there will not be any access via the VK5RWN gateway to the D-STAR global network until further notice. It will only support local operation for the next few weeks.

The current gateway was very shortly due for an upgrade anyway, so the existing failed unit will not be repaired. The new VK5RWN D-STAR gateway computer will be installed on site, pending some minor works, ie, a new shelf, and the final installation and configuration of the new G3 gateway software. This software has to be installed and configured on site as it needs to see both the D-STAR repeater controller and the respective Ethernet ports during the final configuration.

So sorry folks, the D-STAR gateway system will be down until the new computer has been installed, over the next couple of weeks, pending time available.

If you wish to work outside of the Adelaide area on D-STAR, you will need access to a DV Hot Spot, a SharkRF OpenSpot or JumboSpot, DVAP, Dongle etc.

Please pass this information on to any others who you may hear trying to use the VK5RWN D-STAR system

AREG News: September Meeting – Power Supplies

AREG’s next meeting is this coming Friday the 15th September at the Reedbeds Community Hall, Phelps Court Fulham, doors opening at 7:45 pm.

This coming meeting will be another in AREG’s Amateur Radio Beginners Series and the topic for this evening will be, Power Supplies.

Matthew, VK5ZM, will take people through the basics of power supplies, what their characteristics are and what do people need to look out for when selecting a power supply for Amateur Radio use. He will also discuss the pros and cons of Linear vs Switchmode and what makes a good or bad power supply.

AREG Repeater News:

We have noticed that VK5RSB 70cm appears to be dropping coverage. Our fault investigation team will take a look at our earliest opportunity but we suspect a problem with the antenna feeder or connectors. Also the VK5RWN D-STAR repeater is suffering from reduced performance due to mechanical issues with the antenna mounts. Plans are well underway to make repairs at both sites, which we hope will be completed in October.

Contesting news:

AREG is again making plans to mount a portable DX Contest Station for the Oceania DX Contest in October. This will be a QRO Multi-Multi station this year operating from a new site north of Adelaide. We hope to see other VK5’s get involved in this contest this year too, as it is your one opportunity to have the DX stations around the world pointing their antennas our way looking for us! The OCDX SSB contest is being held on the weekend of October 7th and 8th.

In DX News:

AREG wishes Grant VK5GR good luck in his activation of Niue starting next week. Grant should be heard across VK signing as E6AG, Echo 6 Alpha Golf, from September 14th through until September 25th on most HF bands. So keep a lookout for Grant and Grant, goodluck with your operations.

2017/18 Subscriptions now Due

Finally, all AREG members should note that their subscriptions are due for 2017/18. It is a great time to be a member of AREG and this year will be big, with the club turning 20 years old next July – who would have thought! Look out for some special activities throughout 2018 marking the occasion.

So remember folks, come along to AREG’s next meeting, it is this coming Friday evening, everyone is most welcome.

After the formal events, a light supper of tea, coffee and cake will be available whilst you can mingle, review and discuss the topics of the day.

 

VK5RSB Maintenance Day – Battery Backup & 6m Antenna

Since the statewide power blackout last year, AREG has been assembling replacement parts for the battery backup system on our VK5RSB repeater system. Now that this last weekends excitement is over, I am now able to compile and present a detailed report on the working bee at the VK5RSB repeater site at Summertown.

Working bee members,

  • Ben VK5BB
  • Colin VK5ACE
  • Paul VK5BX
  • Adrian VK5ZBR
  • Rod VK5UDX (both Rod and Adrian were on an official task at the site in their employment but were able to spend time assisting at the site)
  • David VK5MDF (invited visitor from NERC)

The aim of the working bee was to replace the cavities on the 23cm repeater, reinstate the battery backup system for the 70cm repeater (disconnected several years ago when the repeater was replaced with one requiring 24v input) and install (finally) the permanent replacement 6m repeater antenna (delayed multiple times in the past due to weather).

Work completed successfully included

23cm Repeater:

  • 23cm duplexer fine tuned (thanks to Paul VK5BX and his Specan/tracking generator)
  • the old 23cm removed and the new one fitted, tested into the antenna and live on air, all good

70cm Repeater

  • the 12 volt to 28 volt inverter installed into rack and wired in,
  • RF power out of 70cm when on battery backup has been set to 30 watts (normally 75 watts whilst mains power is active)
  • repeater tested on battery backup, draws just on 8 amps and puts a “beep” every 60 seconds to identify unit running on battery backup.
  • whilst on site, Paul took the opportunity to “Sweep” the VK5RSB 70cm antenna, return loss was good BUT it was identified that there IS a problem, a ringing or ripple on the return loss sweep, possibly due to a faulty connection in the line. We believe that the problem is most likely the coax connector on the top end of the LDF 450 coax, as this was not serviced or replaced when we changed and fitted the new antenna a couple of years back.This means another working bee, when the weather for working at the top of the tower is conducive.

6m Repeater

  • during the above work activities, Adrian and Rod were able to swap out the old 6m repeater antenna and install the new antenna. Once the new antenna was connected, a return loss sweep was done and all looked very good.
  • with the the 6m repeater reconnected to the antenna, it was still “going nuts” keying up very regularly on “spurious” Checks of the spectrum could not identify any specific signals the could be causing this other than the high noise floor. So Adrian wound the mute setting a bit higher and this fixed the regular intermittent keying of the repeater. (subsequent observations and reports are that the 6m repeater seems to be working very well and is generally quite when not being worked)

A big thank you to everyone who contributed to the work at VK5RSB. I am sure it will improve service for all amateurs in the greater Adelaide Metropolitan area.

VK5RSB Repeater Extended Outages

Photo of downed powerlines courtesy ABC News

AREG’s VK5RSB Summertown repeaters  have been off air since Tuesday evening’s violent storm which has taken out power lines that feed the site. The restoration work according to SAPN is still progressing. The latest estimate for restoration is now 1.00pm today (31st December)..

We apologies for the outage on these major Adelaide repeater services, and are looking to see what can be done to reinstate the battery backup at the site which has failed.

VK5RSB 23cm is back !

repeater tower clipartThe VK5RSB 23cm repeater is now back online.

After a couple of hectic weeks Colin VK5ACE has made the necessary repairs to the 23cm repeater and put it back on the hill.

If any users observe the repeater doing something odd please contact us on the email addresses (here).

Many thanks to Colin for all the hard work getting this service back on the air again.

73, Matthew VK5ZM