Surpise, surprise, it works!

 Flarm, Tracker  Comments Off on Surpise, surprise, it works!
Dec 182020

After building a nicer box for the electronics, I used my Acrowot as the test-bed of choice, the motor mount is loose, the battery is 7 years old, but hey, just enough oomph for a test. Anyways, looking at the data, I am very happy. My receiver on the shed even picks up the signal when I am in the pits, I had not expected that. Higher up is no surprise of course. The signal is much stronger than what I usually get from Real Planes. (Our field is only 1.3 km from my receiver. I do catch full size planes as far as 30 km away, when I have a clear line of sight.)

There’s more info about the story here.

Ye ol’ acrowot, forever going strong!

So, now it’s a matter of putting this contraption in the bigger planes, and get some more data. Don’t forget this is built for full-size aircraft, to allow them to spot nearby traffic. When you see 1900 foot/minute ascends of this tracker, you know it’s either a UFO or a model-airplane! The number of data points is relatively low, but enough to make them big ones know I am there! I took this image while in the pits, plane on the picknick table: still 4.5 dB signal, even though there are buildings and trees in the way. Speed is of course determined by GPS readings. Even when stationary, it will show movement. (All GPS-es do this, usually it’s the software that filters this away, but we likes the real stuff, not all smoothed)

Lots of wigglies, after 3 flights, my battery was empty.
These are all data points from all aircraft since beginning sept 2020

As you can see on the heatmap above, lots of data when I was in the pits, sorting out my ailerons (reversed) motor (reversed). I also noticed that the fixed motor mount is more of a flexi-mount at the moment. It explains the funny behavior of the plane at full power. Anyway, not worried about that, that was not part of the exercise. Below is some raw data: (first number is time in GMT, then coordinates, altitude, rate of change, acend/decend, heading, and some more stuff relating to reception of the signal.)

122704: [ +51.86655,  +6.15268]deg     3m  +5.3m/s   3.2m/s 341.7deg  +0.0deg/s Dm4 03x05m Fn:00_o_ -0.86kHz  4.5/20.5dB/2  1e     1.3km 185.1deg  -0.8deg    !   * 

3 meter altitude, 20.5 dB signal!

122207: [ +51.86728,  +6.15048]deg   103m  -3.9m/s  20.0m/s 059.7deg  +0.0deg/s Dm4 03x05m Fn:00_o_ -0.76kHz 13.5/27.0dB/0  0e     1.3km 192.3deg  +3.5deg  

and 100 meter, 27 dB. I honestly had not expected those numbers.

And from GliderRadar more raw data: even going down in a hurry (2000 ft/min) it tracks nicely. The highest altitude recorded was 784 ft, (239 meter) which of course is also nicely shown on glidertracker.

12/18/2020 1:27:37 PM+01:00: FLR66052A>OGFLR,qAS,Elten:/122736h5152.08N/00609.05E'071/037/A=000285 !W53! id3666052A -1979fpm +0.0rot 11.2dB -0.9kHz gps3x5

After seeing this, there is no need to try to build a better antenna, these stubs do rightly!

And just to explain why I did all this: The picture below tells the story, a full size heli, flying at 93 meters, at well over 100 km/hr, where I was a few minutes earlier. Next time he does that, he will get lots of alarm bells in his ears!

With this subject out of the way, I can start making snow for Xmas again! (More sanding wings…)

I hear someone thinking: If I wanted to use something like this, but I am not near a groundstation, would that work?

I am sure I could use a mobile receiver setup, and link to ye interwebs through a GSM phone. The amount of data is not high, only what the receiver sees from passing full size traffic and whatever you fly yourself. Sounds like a project, most of the stuff is looking at me.

  • Raspberrypi, connected to GSM as hotspot: easy
  • RTL-SDR dongle: got it
  • Antenna : done, it does not have to be high, since you only want local traffic.
  • Some Battery for power: take your pick
  • But if I don’t have a GSM/Signal? You never worried before, just keep on flying!

Sounds like a fun project, lets do it!

Could not let it go..

 Flarm, Tracker  Comments Off on Could not let it go..
Dec 152020

It’s one of these things I knew I could fix, if only I would just concentrate. I’m talking about my almost nose to nose encounter with that heli-boy a while back. It sure did scare me, tell you that! Anyway, we now have the Technology, so next time, he will see me/us.

The Technology is a so called tracker-device that is used in more and more full size air-planes. It’s an open source project, so the costs are peanuts compared to the existing equipment. Within the protocol there is a type of plane ‘Drone/UAV’. For my purpose that’s close enough to the truth.

It’s basically a transmitter that sends it’s location to the nearby receiver on top of my garage. The location is then shared over the Interweb, and all planes that have FLARM receivers, will see the position and hopefully take action. (very short, very much simplified version) (See OGN for an introduction)

Since the receiver is only 1300 meters from our flying site, I hope to be able to pick up the signals from the transmitters. If not, we’ll sort it!

So with some luck and dry weather, I hope to try this for real in the next few days/week/whenever.

Flarm tracker

 Flarm, RapsberryPi, Tracker  Comments Off on Flarm tracker
Jul 312020

In the summer of 2020 I had the idea that I wanted to let full size pilots know where we are flying. There is no easy way to do that. But then I found the Open glider Network. What started out as a ‘just for fun’ project, turned into something that I don’t want to fly without anymore.

In Dec 2020, I encountered a heli-driver, going full speed straight across our field at less than 300 ft, where I was a few minutes earlier.

Some references:

First I build a OGN-Groundstation, and was lucky enough for someone to keep flying nearby.

Thank you D-IAPD
and then he went home ..

In short, the photo-plane had connections to the Gorinchem node. (The fellow has a good 9 dBi antenna mounted above rooftop.) and to other stations more then 100 km away. Since the signals really depend on line of sight, you can bet they are higher up then I am! I already noticed that the Eltenberg is in my way 😉

Long story short, if you want to play you need a 9 dBi antenna. Yikes.. Hard to beat, but there’s no fun without a challenge!

First impressions (antenna way too low!) this plane was tracked to 12 km, when I had a good 10 dB signal. You can have good data to as low as 0.8 dB, if you can see the plane! so hopefully that part will be rectified RealSoon.

When I am higher, I can start playing with the antenna design. (FYI, all this 868 Mhz stuff is also applicable to 2.4 GHz systems. See where I am going?) No better way to learn then try to create and solve your own problems!

Let’s also say that apart from several air-plane types that are tracked, there are: Obstacle and UFO. I’ll forget the UFO for the time being, but Obstacle could be interesting. Park an obstacle at our field and the big boys should take notice!

Of course this is not something you do, just for fun, much discussion will have to follow. But imagine the future, when the whole world has their pizza delivered by drone, you can put an obstacle in your backyard and say: not in my backyard!

Yes, this all has to do with the regulations being forced upon us. Better to know and understand then to wake up one morning and find out we’ve been administratively cleansed!

So no cutting of metals this week? Yes/no/working on it. I never quite got the ancient software to play nice when cutting layers. In wood that don’t matter too much, in metal, things start to smoke or bend. working on it!

Anyways, it’s hot outside, still 30+C at 20:00. I’m calling it a day!