HAM APRS Tracker – Byonics to the Rescue – sort of.

APRS Tracker Issues – an Amusing Response.

In Australia to use an APRS tracker you will need a “full call sign” for an amateur radio operator. A foundation or other license is not good enough. We use these trackers by always ensuring that we are not putting it on to a commercial payload, or that the commercial payload agrees to space in their payload for community experiments. We always use 2 trackers and they simply may be a pair of SpOT trackers or a spot tracker and APRS. At times we have even used 2 APRS trackers with different SSIDs (identifying codes)

My High Altitude Balloon (HAB) work just got made a little easier. My old trackers were all starting to fail. I just took delivery from Byonics of one of their MT2000 HAM radio APRS trackers. This is only for licensed Ham Radio operators and it is a sweet device for its size. It can output over 2W of power and has a full transceiver on board. It is easily configurable and runs off 5v to 12v. I think power output is a bit less than 500mw at 5V. It is as light at anything and easily programmable as I also bought the USB cable – a 9 pin D connector for RS232 slips over the end and I will solder it in place. I usually slip a VHF antenna right on the end (red cover cap) and I will solder the special GPS receiver in place on the board. There is still a connector on the GPS unit. It should be noted that these GPS units are configured to work above 60,000 ft as most GPS stop there. Don’t try using the GPS in your phone for tracking on a balloon!

Hey, before I go too far with the Tracker, here is a video from one of our flights. Made for MYOB, it shows the quality of our work. This payload was extreme and we built it on the spot from a wooden frame prepared the night before:

I suggest that you click full screen to get the real impact of this video! In fact go to YouTube and it is really HD

https://www.youtube.com/watch?v=tvWjNYja8xA

The payload had 8 cameras 3 power banks, 6 voltage regulators, 1 actuator and 2 trackers. One camera was a Fly360 x 240 camera.

Back to the tracker:

https://www.byonics.com/mt-2000

Here is what they say:

The Micro­Trak 2000 (MT2K) is a frequency agile, 2 Watt, programmable miniature APRS (Automatic Position Reporting System) transmitter utilizing a TinyTrak3 controller chip and is capable of operating from 144 to 148 MHz.

Just plug in a GPS receiver, such as the Byonics GPS5, add a SMA antenna, and start tracking!

  • No need to tie up an expensive radio for APRS tracking
  • Simple 2 wire GPS connection
  • Supports all the latest Byonics TinyTrak3 features.

Note the special GPS block in the picture below. That is what to look for:

Byonics MT2000 APRS Tracker

APRS Tracker Failures – Why?

We could not get an answer to this question because we are simply too good at recovering the units.

We insulate them with bubble wrap, but the super low temperatures in the jet stream (-50ish C) seem to affect the devices over time. Several have died. When I asked Byonics the question as to why, it appears no one can answer me. It seems customers always loses their trackers and we seem to only notice this problem because we have never lost a payload and keep using them. It looks like they only last about 10 flights with super low temperatures and super low pressure. If this works as expected, then I will have to order more. Everyone else loses them by this time. I expect it is a temperature issue and we will try and compensate of update our units after about 7 flights.

Configuring your APRS Tracker

The important parameters to specify for preconfiguration when ordering from Australia for a MT2000 balloon tracker are:

Your HAM radio Call Sign with the appropriate SSID. Mine is VK2URB-11

The Digi Repeater parameters:  WIDE 1-1

The Australian APRS frequency:  145.175MHz

Transmit interval:  every 20 seconds – no receiver check

Symbol:  /o balloon

Any appropriate text:  mine is “UpLift Balloon”. Keep it short as it makes the transmit packet bigger.

Watch out – other countries use different frequencies

Space Tools – Reaction Wheel Fun

Reaction Wheels are Great Fun

How do you keep a spacecraft large or small stable in space? Reaction Wheels are one way. Writing software to control one reaction wheel of four is tough, but this toy/tool lets you test them. at least if they are small.

A reaction wheel Test platform

I love playing with this beast. it is to simulate the operation of reaction wheels that are used to stabilise small spacecraft. I was at Sydney Uni discussing our StratoDrone and how to build a test flight involving a zero pressure balloon. More on that later, but we now have a plan. This reaction wheel test jig is hugely expensive and it sits on a partial ball that then sits on a vertical stand in a half hemispherical hollow fed by air. Basically it floats on air and the reaction wheel results are clearly seen. You can test your electronics and your programming. Although these are bigger than those used for a cubesat, they still work the same and produce this visual action. It of course does not go around fully as in space. It hits limits in the ability to roll and pitch, but the actions can be seen clearly. I love this tool so much.

You can also see that the various axis are written on the perspex above the reaction wheels. There are only three needed in a basic unit, but 4 are often provided in case one fails. It is placed at such and angle that it influences all three axis. If one fails, then the 4th replaces it and the working two have to counteract the influence it has on them. It means it also has to spin 3 times more to achieve the same result in replacing the faulty unit.

There are other platforms and ways to test reaction wheels. even hanging a test object on a long cord from the ceiling will give a good indication of what is happening at almost zero cost, but this tool is way more elegant and will give a more accurate result.

I love space toys! – erh – I mean space tools.

When to use a Reaction Wheel

The ISS uses Gyros and not reaction wheels. They are not the same, but I will not go into that in detail here, but I will say that Gyros don’t always work. They reach a stage where they get saturated and require a sort of reset and thrusters are needed to get things stable again.

A control moment gyroscope (CMG) is an attitude control device generally used in spacecraft attitude control systems. A CMG consists of a spinning rotor and one or more motorized gimbals that tilt the rotor’s angular momentum. They are big and heavy. They are used on board the ISS and spin constantly. No manned craft or craft visiting the ISS has ever used gyros. A gyro can exert torque along any axis by turning the gimbals. It is also very big and heavy. The whole assembly is roughly spherical in shape.

As for reaction wheels, once the reaction wheel reaches its maximum angular velocity, it must be slowed down and the resulting torque must be counteracted with thrusters. Usually there always are some reaction control thrusters and if precise attitude control is needed, there are reaction wheels in addition to thrusters. The reaction wheels maintain precise stability until they reach their limits. They are however very useful for cubesats. Cubesats may also be further stabilised along the earth’s magnetic field by the use of a powerful magnet on board the spacecraft. care must be taken in the design for the reaction wheels not to fight the magnetic orientation.

Stratosphere Flier Takes Shape

Stratosphere Drone

First, an apology. We have been too busy to post too much. Life gets busy. This update may surprise a few of you as it is a massive project and it will take millions of dollars to complete, but tests have begun and a Joint Venture with a Sydney University is in the wind. I was there 2 days ago working on our first dedicated test flight using a super pressure balloon and flying the unit to the stratosphere. hovering for a while and then descending back to earth. It all costs money and we are looking for a sponsor of course. The concept and initial designs are also in front of the Australian Air Force as this will be an obvious watch dog for anything from battle fields to border protection. Drones with wings are used at the moment and they are hugely expensive. This will be a fraction of the price of operation and initial cost.

We have nicknamed it a StratoDrone for obvious reasons – it lives in or just below the Stratosphere. We need to finalise the image before we get ahead of the objectives, but it will look something like the image here. This is drone is not space, but the opportunities for space research are enormous. As we at ThunderStruck Aerospace (our commercial business)  begin the long task of produce our own our StratoDrone, we start with a shape and test it on the PC and in any wind tunnels that we can use., it takes shape, morphing slightly as we test the drag and flight parameters. This image is the first pass. It is way to big in the tail and there needs to be a better tapper along its length. The tail fins need to be about 1/4 the size. There is no steering on the fins although I am considering a gimballed set of rotors on the very rear. This would have to be a sunset image with the light so low. The StratoDrone will sit on station at 20Km or higher or lower depending on winds.. The instrument Nacelle will be slung under the forward ring and is not shown at this angle. The StratoDrone is expected to revolutionise communications / radar and observation, bush fire fighting and almost anything. A stunning video of its operations and capability will be available soon. This is a sample photo only and not the final product.

StratoDrone in flight headed to the Stratosphere

The Stratosphere or Bust:

This was posted on Facebook and the comments were:

Comments were:

Robert Brand: Hey, John, we are starting on our StratoDrone. it is not for people, but equipment that can stay stationary in the sky – “on station” for months at a time, or cruise the coast for erosion, illegal fishing or whatever. The cost curve to operate is way under commercial drones and the ability to stay in one place a real opportunity for telecommunications. It is not space, but the future is one step closer. By the way, the gap between the troposphere and the Stratosphere is called the Tropopause. We live in the troposphere and so do the jet streams. The Stratosphere starts at about 16Km to 20Km (10 miles to 12.5 miles) altitude depending on your location, season and more.

Victor: Wow !!! I have been looking for a static drone for 30 years ! My dreams come true ! ya I know a blimp is great! Any Facebook page for it ?

Robert Brand: In case anyone thinks that this platform is not a massive benefit to space, let me suggest 2 uses to start the ball rolling.

1/. Stable telescope platforms
2/. Comms downlinks with massive coverage

Telescopes – Imagine being able to launch a 100Kg telescope to close to 30Km altitude and only have 1% of the atmosphere above you. Without the earth’s atmosphere to interfere with observations,you might as well have a telescope in orbit only this one you can bring back down and swap out the payload the next day and relaunch. The opportunity for space research will take on a whole new meaning with short low cost refits and redeploys within a day. Somewhat a cross between NASA’s Sofia aircraft and a low orbiting spacecraft. Other sensors can be fitted without having to wait for a launch of a spacecraft.

Communications – Unlike ground based radios, that can only see a spacecraft from horizon to horizon with all sorts of caveats such as mountains that may block the signal, thick atmospheric issues that will attenuate the signal, being 20Km to 30Km up, a passing spacecraft will have a good and clear signal available for a much longer time in a pass. The footprint to communicate with passing craft and the signal strength necessary will improve greatly. In other words, it will have acquisition for much longer and accept much lower power levels. This makes it an ideal platform for a whole range of things, but especially as a downlink for small spacecraft such as cubesats. Uplinks are usually not an issue as the ground can increase its power levels to make comms easy. The StratoDrone however will be able to see further than ground based systems, thus increase the number of viable passes possible.

These machines may replace many spacecraft functions, but mainly to free them up for other projects. The most congested radio frequencies are for geostationary spacecraft at 36,000Km altitude. With this technology, we are effectively a geostationary object at 20Km altitude. The possibilities are endless and the emergency facilities is can provide when ground based infrastructure has been destroyed is phenomenal. Once these machines are fully operational, they will be here to stay..

There is no page yet, but I will be posting an update here soon.

http://thunderstruck.space/

Steven: Very interesting Robert. What is the payload mass for your balloon? How do you deal with the problem of high altitude wind?

Robert Brand: We sit at the transition between the stratosphere and troposphere. The winds are minimal in the tropopause. The occasional reversal of winds creates an issue. This does not happen between the tropics so it is best use is southern parts of the US and northern parts of Australia or in most of the worlds trouble zones. Payload mass maybe 100 to 200 kg. Maybe much more depending on the final size of the machine and the maximum altitude.