Tracking Equipment and Mobile Technology
One of our big issues when working with balloons and supersonic gliders is that they never stay still. Even our balloon flights have reached an astonishing 230kph over land by simply climbing through the jet stream. Basically, the car can’t keep up. Even if we could travel at such mind-blowing speeds, we could never follow the same path and have to stick to roads that crisscross the landscape and never in an easy route across country. Mind you a recent flight did travel straight along the Mid Western Highway and have the courtesy to land within a few hundred metres of the main road in sheep grazing paddock. – no crops and no trees.
Simply we need to have not just good tracking, but great tracking. That is where the car needs to be able to cater for several technologies and that means radio and wireless data connections. Our car has just this capability and we need more. We have chosen a Pajero 4WD as we will need some rugged ability for off road work. In the past we have had to drive right through a 200m bit of forest without any road or fields that may have had animal burrows. over logs, through streams and much, much more. The Mitsubishi Pajero Escape is an older model, but still good and we have used it for balloon flight tracking in the past.
In Australia, the most common tracking for High Altitude Balloons (HAB) is via either HAM radio APRS for non commercial activities and RTTY on UHF for commercial activities.
Ham Radio APRS
APRS stands for Automatic Packet Reporting System and is a digital communications information channel that is capable of handling information such as GPS (Global Positioning System) data. This is ideal for tracking balloons. Ham radio hobbyists simply build receivers and port the data to a central server. Several receivers may pick up the signal and port the data which i recorded in the database. In our case every 20 seconds. The frequency of the reporting interval is important as the payload gets near the ground so that the radio can easily be located. In some areas there are no receivers and internet connections – known as iGates. Care needs to be taken, but the solution is to have a mobile iGate in the car if there is good mobile wireless coverage in the area. We are preparing to have a mobile iGate in the tracking vehicle. Until then we have a high power APRS repeater. It receives the data and resends it to an iGate that is in range. Occasionally this is in another of our tracking vehicles and the ability to relay is important. If you want the full details, you need Internet connectivity in your vehicle, either through a tablet or PC.
In Australia, it is illegal to use APRS to track commercial flights. We have to use something like the globally accepted UHF RTTY system. RTTY in Australia can be on multiple channels on 434MHz. and can only be 10mW of power. This is fine if you have height and can track to the ground. As with APRS, you need to be nearby when the unit is near the ground or the curve of the earth will cause the signal to be lost possibly 1Km above the ground. on a windy day this can lead to a big search area. Similar to APRS, there are many people that place a UHF RTTY gateway in their vehicle and gate the data to an internet server. If you want the full details from the server, you need Internet connectivity in your vehicle, either through a tablet or PC.
What is Installed in the Vehicle So Far?
Let’s do a list of the basics:
- A Kenwood D710 APRS capable transceiver (VHF/UHF) with tracking display and GPS integration
- An Icom IC-7000 all band HF/VHF/UHF transceiver that is RTTY capable (but does not display tracking)
- An 80 channel CB radio on UHF (in case we have a non ham radio car in the group
- A Byonics MT-400 10W APRS Beacon
- A wireless mobile modem with a wired and WiFi router (so to have an external antenna) runs of 12 volts
- A motorised antenna raiser – the big antenna hides in front of the roof rack and is near invisible.
- A multi-socket cigarette lighter system for power for many items
What we need to be installed
Let’s do a list of the basics:
- HF radio antenna (we have the Icom -700 HF radio side hooked into a 100w termination for safety)
- An auto-tune system for the HF radio
- Another big VHF/UHF antenna with a motorised lifter.
- 2 x 900MHz antennas
- A 900Mhz antenna for 56Kb modem access to the balloon and ThunderStruck systems
- Radio Controller as used for flying model aircraft
- A video downlink on a band to be decided.
- A visor and screen display for the video from the balloon payload and ThunderStruck aircraft.
So we are already halfway there, but still have a long way to go and need your help with funding. More on that soon. It is clear that we have a lot of this gear tested and bedded down and that is a good thing. Part of my requirements with this vehicle is to make it inconspicuous. Being old is a start. Hiding all the antennas is another. One antenna is super thin and near invisible, another is very short and the last folds down in line with the roof rack. The photos below show the antenna folded down and raised.
The antenna can be raised when driving and it lets us enter car parks without a second thought. We have a switch on the centre console, but i am thinking of adding a proximity alarm in case we forget that it is up. That is the switch to the right of the cigarette lighter. Sorry for the debris under the switch. We had just finished installing the Icom IC-7000 above it.
In the picture above, we could have mounted the unit under the dashboard, but it is a little more versatile being accessible. I also took the opportunity to hard wire the GPS Navigation unit directly to the car wiring. Since the 12 volt plug has the 5V system, we ensured that the charge unit from the plug was in circuit.
Note that I did not change the frequency to 434.650MHz or similar frequency where RTTY resides. I just wanted to show the fact that it does RTTY. The output at the back of the radio connects to an interface box and can then connect to your PC.
Note that the IC-7000 display is only a front screen. There is a cable to the base unit under the driver’s seat. it is wired so that the microphone and front screen can be moved to the rear seat so that an operator in the rear of the car can operate the unit. Similarly the base unit for the Kenwood is also under the drivers seat.
Note that the unit above has its GPS hard wired. Like the IC-7000, it is a dual VFO. Only the B VFO is displayed above, but you can operate the VFOs on different bands or channels. It is very versatile.
The image above is displaying the rough compass direction to the station displayed. It shows an actual bearing (325 degrees) to the target and there is also a distance in 100m increments. Since the beacon was very close, it shows 0.0Km. A second display shows position altitude and speed.
Finally the above shows our mobile hotspot unit. It still needs its external antenna for really good mobile coverage, so it is temporary. It uses the rear 12 volt outlet next to the torch (bottom left) for power and once the antenna is installed, the modem will not be on the cable, but plugged directly into the TP-Link unit. We also have 4 hard wired network connections for future units such as the mobile iGate.
Also note that there are two other trackers on board that I will not disclose. It has significant anti-theft devices and tracking, so don’t come after this car. it might just get you caught.
Anyway, we are halfway there for Project ThunderStruck. We are extremely ready for any High Altitude Balloon flight.