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.
Firstly, Happy New Year 2019 to everyone. This year promises to be yet another action packed fun filled series of events brought to you by the members of the Amateur Radio Experimenters Group.
Next Meeting – Friday January 18th – 7.45pm
The next meeting of the Amateur Radio Experimenters Group Inc will be held on Friday the 18th of this month. The topic of the evening will start with a short introduction to the world of remote HF SDR receivers and how to access them.
It will then be followed by a workshop event looking at the original AREG project intended to setup and host one of these systems here in Adelaide. The original project was plagued with problems, most notably getting an internet link out to the site some 40km away from VK5RWN. In the end we weren’t successful in getting the microwave link to be stable. The secondary issue of local site noise at the receive site was never even addressed because the internet feed couldn’t be resolved.
Now that 2019 is here, and the opportunity of a new site has presented itself (that solves the internet access issue), the club is looking for members to form a new team to try and complete the project. The second half of the meeting this month will explore what tasks need to be done to make this a reality and we will be looking for volunteers to put their hands up to help
Visitors are always welcome! The club meets at the Fulham Community Centre, Phelps Crt, Fulham from 7.45pm. The presentation starts at 8.00pm and will be followed by coffee and cake before a formal business meeting.
AREG will again have a stand at the Adelaide Maker Faire on this weekend. The faire runs from 10am to 4pm this Sunday, at the Tonsley Innovation hub in Adelaide’s SE suburbs. The AREG team are planning on showcasing a raft of things that link making and building with Amateur Radio.
AREG is stand number 76!
What will AREG be doing?
If you have ever wanted to find out more about our Project Horus high altitude balloon program, or radio direction finding, satellite tracking, home built magnetic loop antenna construction and much more then this is an ideal opportunity to come and talk to the club members about some of their regular activities and how they are always “Making Things” within the hobby of Amateur Radio.
One of the new projects on display will be the satellite tracker based on an earlier project by Joe VK3YSP and Julie VK3FOWL from SARCnet in Victoria. As an open source project, AREG members have been adapting it to track balloons based on the received GPS telemetry from our payloads.
So why not come on down! We would love to see you there. On site we hope to have a handheld listening on 439.025. We would also love to make QSOs with people on the VK5RSB 6m repeater (53.75MHz / 52.75MHz) which we will be accessing using a magnetic loop antenna from the site.
Update – July 12th: Mounting of the tuning capacitor and motor drive is complete. Just a few more things and we will be ready for final assembly and tune up!
A group of members inside AREG, inspired by Steve VK5SFA’s success with his transmitting magnetic loop antennas have banded together to construct for the club it’s own 160/80m TMLA, specifically designed to be portable. It is able to be knocked down into components that can be packed into the back of a station wagon.
Significant progress was made today in assembling the antenna as we had hoped to have it ready to try at the IARU HF contest next weekend. We didn’t quite make it unfortunately, running out of daylight before we completed construction. However, we are now planning another session next weekend with the goal being to have the antenna finished and ready to run for the Trans Tasman Low Band Challenge contest the following weekend.
The club’s version of Steve’s antenna is using LCF78 coax instead of the wave-guide, with the vacuum capacitor mounted inside a water proof ex-camera case (great for transport and moisture proofing). The frame is made out of laminated bamboo broomsticks and a timber hub arrangement with the frame held together through compression provided by 8 ratchet straps. The aim is for the antenna to be suspended from a tree (or trees) at least 1 loop diameter above the ground (to increase it’s efficiency). It has been designed to accept 400W input power as well to overcome the efficiency issues these antennas can have.
Today’s construction efforts were led by Steve VK5SFA, Grant VK5GR and Scott VK5TST. The project wouldnt have been possible without generous donations from Steve VK5SFA, Peter VK5KX and Trevor VK5YFR.
The next steps are to complete mounting the motor tuning drive, do some structural adjustments to the frame, assemble the coupling loop and then test the antenna. This work will be completed next weekend, so keep an ear out for us during the TTLBC Contest on July 15th on 160 and 80m using our Transmitting Magnetic Loop Antennas!
SORRY! ALL SOLD OUT on APRIL 1st 2017– Stay tuned next year for more Amateur Radio products from the mad scientists division of the Amateur Radio Experimenters Group!
After months of rigorous testing, the Amateur Radio Experimenters Group Inc is pleased to announce the beta version of our new DX Buster(tm)! is nearly ready for initial release. What is it you might ask? Well, it is designed to help you to break through pile ups during DX Contests and DXPeditions, ensuring your signal is the one heard clear and true, first time, every-time!
There will be no more disappointment that the DX got away when you are using a DXBuster!(tm), even if you are only a small 100W pistol or 400W VK “high power” station located more than double the distance from that rare DX station compared to the majority (as is often the case when comparing VK to Europe, North America and Japan where they run 1kW or more). Now, with DX Buster!(tm) on your team, you can rest assured your signal will always be clearly heard among the pileups at the DX stations end, guaranteeing you will get that rare one in your log, even with modest power.
How does it work?
DX Buster!(tm) is a DSP device you insert into your microphone audio stream, and then also connect to the Internet. It works by mixing your transmitted audio with an anti-phase, time correlated / corrected version of the signals that the DX station is listening to, based on what is being received via any WebSDR located close to the major source of the DX calling pile-up stations.
Using patented Flux capacitor technology, and augmented by feeds from the Reverse Beacon and PSK Reporter systems tuned to the WSJT JT65 networks as well as space weather predictions from the NOAA and Australian Bureau of Meteorology, the propagation channel between your station and the rare DX is computed. Then, the anti-phase signals matching the majority of the pile up stations within 4kHz of your signal are delay matched to your station and then injected into your audio. The rest follows the laws of physics! When the out of phase signals are combined at the DX stations receiver with the other pile up traffic, that traffic is attenuated, while your own audio laid over the top passes through unaffected. The end result is a minimum 10-30dB improvement in your apparent signal to noise ratio as measured at the DX station.
Don’t quite believe it? Take a look at the following waterfall charts and sample audio streams to be convinced!
How can I get one?
Currently only a prototype of the unit is available, as a number of technical details are still being refined to make it adaptable to as many transceivers as possible. As soon as these are resolved, we will open our books for orders!
On October 18th the AREG installed a new 5.8GHz wireless link into the VK5RWN repeater system.
The system is on test for the next couple of weeks, the results have been very promising with the link providing in excess of 30Mbit throughput (full duplex). Certainly many times faster than the current 512kbit symmetrical ADSL connection.
Once the wireless link has been finally commissioned and cut over the AREG will be able to close the current ADSL and Telephone internet connection which will significantly reduce the on-going running costs of this site.
I’d like to thank Bob VK5FO, Ray VK5RR, Andy VK5AKH and Mark VK5QI for assisting me with the installation and setup of both ends of the link.
Thanks to the hard work of Ben, VK5BB, our IRLP node is back up and running on VK5RSB 70cm. The usual access conventions apply, and currently no access code is required (though this will change shortly).
To accommodate the (often quite busy!) drive-time nets, the IRLP node is automatically disabled between 7AM to 9AM, and 4PM to 6PM. Enjoy the node, and please make sure you identify before using it, even if just checking the node status!
therefore you need to change your portable and mobiles to reflect,
Mbl/Port Tx 147.6375 MHz
Mbl/Port Rx 147.0375 MHz
Set Rptr1 VK5RWN C
Set Rptr2 VK5RWN G
The frequency change has been brought about due to adjacent channel interference from the VK5RLH 2m repeater at Lochiel causing problems for some users mobiles and portables. These frequency changes are temporary whilst we evaluate the impact of the changes. If it works out OK, then AREG will apply for permanent changes and fix the frequencies.
Please let any other users know of the changes.
Advice will be promulgated via the National and Local Broadcast News and Notes, the AREG Web pages, www.areg.org.au, the D-STAR VK5 web pages.