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Airplane Tracker

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petehowell

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I have always wanted a gizmo that would allow people to track me realtime while flying. The Spot gizmo that dr has is really cool, but those of you who know me, know that I am homebrew kinda guy. That, and I hate subscription fees. (I am a wee bit on the frugal side - Thanks Mom!)

So I looked into something called APRS Automatic Position(or Packet) Reporting System. In its basic form, it uses a small transmitter to send your location (from GPS) to the internet using radio repeaters and eventually an internet connection. The information shows up on a Google maps interface on the web in near real time. And the best part - it is free! Using this system requires a Ham radio license, but I found that easy to obtain by passing a 35 question multiple guess test and paying $14.

Here is how I equipped N789PH for APRS.

1) I ordered an APRS Gizmo as a kit and built it. You can buy them assembled as well. It was fun and easy to build. I added a puck GPS and antenna. Total cost. ~$185 delivered

Here is the gizmo - it is a tiny transmitter and the device that encodes the GPS info into packets.
2003338780126364737_rs.jpg


Here it is after I packaged it:
2003325422402343563_rs.jpg


One more as I was programming it:
2003394530496790147_rs.jpg


Here is my install. The thing weighs about 6 oz and is darn close to the CG. All it needs it a few milliamps of 14V when transmitting. I pirated power from the LED Nav lights.
2003343198288029526_rs.jpg


2003312768918054734_rs.jpg


2003347471714018365_rs.jpg


The antenna is a homebrew design I found on the web made out of old twinlead 300ohm TV antenna wire.

http://www.scribd.com/doc/267393/An-Easy-DualBand-VHFUHF-Antenna

If you don't want to build an antenna - help a kid get to Alaska http://www.vansairforce.com/community/showthread.php?p=199582#post199582

The install with Gorilla tape is temporary. I will glass it in now that I know it works. I was able to send signal to stations over 100 miles away with the tiny transmitter!!

Here is what shows up in realtime on the web:

http://aprs.fi/?call=kd0cvn&mt=m&z=11&timerange=3600

here it is in a pic:

2005444355428275454_rs.jpg


So there it is. If you like to tinker and want to save few bucks, give this a try. If you just want tracking for safety and want a turnkey and more robust solution - buy the Spot. It is good to have people know where you are.

I had fun making and tweaking this thing. I also learned about Ham radio and met some guys in the local amateur radio club. They are a lot like exp airplane guys, friendly, and looking for a better, cheaper way to do things.
 
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Good stuff, Pete. I'm an old school extra class (N5QCN).

I'll have to order one of those and give it a shot. I really like the idea.

73,
Phil
 
Altitude

Neat...
Does it report X-Y-Z location, or just X-Y?

gil A

I guess my KE6HAP license would cover it....
 
It reports altitude as well. I've got the 8Watt version installed because the repeaters are a little sparse in my neck of the woods. The low power version "works well on 9-15 volts DC" whereas the 8 Watt version "runs well on 12-13.6 volts DC" and runs at reduced power below 12Volts. I installed a regulator ( http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2494 ) that works very well. Anything over 12V get regulated down and anything under passes through. I also bought a "stealth Antenna" ( http://cgi.ebay.com/Phantom-Antenna...210679586QQihZ017QQcategoryZ296QQcmdZViewItem ) and mounted it on the bottom of the airplane. The designer of the MicroTrak is very active Yahoo!Groups and is constantly expanding his products. I've been happy.

--
Michael Crowder
 
Range and coverage will vary

Hi Larry,

In the flat hinterlands, coverage should be pretty good, especially if you are flying high. As you get into the mountains, it will be less. As Michael indicated, they make a hi-power version that should be better in the big rocks area.

It looks like repeater coverage in the western Dakotas and Eastern Montana is a bit sparse. I'll find out this summer when I fly to Big Sky. There is an add on RF amp for $50 if I find I need more power.
 
Micro-Trak

Pete,
Where did you get that gizmo? Way Kewl!!! all I was about to find was AG stuff. Post a link.
Mike H 9A/8A
 
I'm with you, Pete, subscription services tend to get my homebuilder juices flowing too.:D I've been using APRS for several years, mostly for balloon tracking, but also in the airplane. When I flew down to Key West last year in my 182, my friends and family were able to monitor me (especially when ATC routed me down low over the Everglades due to a Miami Presidential TFR)! It was nice to have our friends waiting for us at the airport because they had been tracking our flight and knew as well as we did when we'd arrive! Another nice feature of APRS is the ability to send simple text messages.

There are a couple of APRS user forums, one specifically dedicated to airplanes - it's called aero-aprs and it's on Yahoo. (http://groups.yahoo.com/group/aero_aprs/). Not too active, but your post identifying your installation would be appreciated there, Pete! There's a guy named Joe Dubner on there who wrote a web page app for tracking airplanes, so its got some special features dedicated to that kind of tracking. He's a great guy, built a Long-EZ and just started an RV-8.

The other yahoo group is dedicated to the family of hardware that Pete and I are using, made by Byonics (link above by Pete). The Yahoo Group is at http://groups.yahoo.com/group/TinyTrak/

I purchased an identical Byonics Microtrak 300 to put in my RV-7A, but haven't gotten around to installing it just yet. Sounds like your antenna is working out well, I might just have to copy it, so thanks for the link!!
 
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I'll have to dig out my ham license and see if it has lapsed. Looks like a fun project.

Edit: Found it and am good until 2012

KB5RRN
 
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Antenna

Pete:
Would zig-zagging the antenna up and down on roughly 45 deg. angles in the wingtip help get more vertical polarization, or is it fine the way it is?????
 
Don't Know....

Hi Mannan,

I was worried about polarization, but I was hitting digis 100 mi + out with 300mw. I don't think I'll mess with it just yet, but it might be a good idea.

I'll fly a bit with it and if I have coverage issues, I'll make some changes.
 
Current Draw

Here is my install. The thing weighs about 6 oz and is darn close to the CG. All it needs it a few amps of 14V when transmitting. I pirated power from the LED Nav lights.

Pete, I think what you meant to say was that it needs a few MILLIAMPS when transmitting, not AMPS. :eek: It's a 300 milliwatt transmitter (often powered by a 9V battery), so at 14.5V ship's power, you're talking 21 milliamps of current, and this is only when transmitting. The transmit interval can be set to send a packet burst containing your position every 10 seconds, every 30 seconds, every minute, every ten minutes, whatever you want. Every minute or two works well enough to identify your location while not monopolizing the frequency. Bottom line: battery draw is pretty much nil.

Pete, since you connected the transmitter to your LED nav lights, do you leave these on all the time? That's a simple, interesting approach, especially since the LED current draw is also very low. GOOD IDEA;)

On a non thread-related issue, how do you like the luminance of your wingtip landing lights? I'm just now debating whether they are sufficient for unlit strips at night.
 
Thanks Noah

Yes, I did mean Milliamps - this thing will run for a few days off a 9v battery.

I just added nav lights/tracker to my startup checklist -the LED draw very little and more lights on is never a bad thing.

I have a homebrew HID in the leading edge for a landing light, the wingtips are MR-16 taxi and wig wag identification lights. It is a nice light show when they are all on.

Noah, I joined aero_APRS and posted a link to this thread. Thanks for the heads up on that.
 
When??

Hey Pete or anybody with this tracker how about you let us know when your going flying so we can track your flight.:D

Also great idea I'm not ready to fly yet, but I will be building one and using it in my car till the plane is ready.

Thanks for the tip.
 
On the aprs.fi tracking page, there's a link on the lower left for "Google Earth KML". Click that and you get all of the elevation info:

2eehct4.jpg


Very cool Pete! I'm going to have to look into this...

--Bill
 
Pete, that is waaaay coooool! :cool:

Hope you have a disconnect switch for that thing - that is quite an evidence trail!
 
I have always wanted a gizmo that would allow people to track me realtime while flying. The Spot gizmo that dr has is really cool, but those of you who know me, know that I am homebrew kinda guy. That, and I hate subscription fees. (I am a wee bit on the frugal side - Thanks Mom!)

So I looked into something called APRS Automatic Position(or Packet) Reporting System. In its basic form, it uses a small transmitter to send your location (from GPS) to the internet using radio repeaters and eventually an internet connection. The information shows up on a Google maps interface on the web in near real time. And the best part - it is free! Using this system requires a Ham radio license, but I found that easy to obtain by passing a 35 question multiple guess test and paying $14.

Here is how I equipped N789PH for APRS.

This is beyond cool!! I just returned from buying the study guide for the Tech license. I'm gonna build one of these rigs. I already have a Garmin GPS35 in the plane that isn't currently being used for anything. This will be just the ticket for letting the family keep up with where I am while I'm out roaming.

Thanks for sharing, Pete!
 
Four things I like about this over the Spot besides that it's cheaper:

1. You can control when the reports go out. With the Spot they are hard-wired to 10 minutes. And that's only with the more expensive subscription. It's not nearly often enough to make a track out of it when you're cruising at 170 knots. The reports are 30 miles apart!

2. This thing can be built in to the plane and attached to ship's power. Hook it up to something that's always on and you can pretty much forget about it. The Spot needs batteries and you have to turn it on/off and find a place in the cockpit where it can see the sky (i.e. the glareshield).

3. You can share your track with other people. So far Spot hasn't implemented that yet, although it has been promised.

4. Altitude.

This list started out as only 2 items. Hmmm. I might be going this route and selling my Spot.
 
Brian Wizards

The brain wizards that came up with APRS also provided for something called "smart beaconing". It senses when you are turning from GPS data and sends out a position report. You control the turn parameters that trigger the position report to fire. That is how it tracks the turns well on the web interface.

It really is pretty cool stuff, tailored nicely to what we want to use it for.

Geeky Coolness here:

http://www.hamhud.net/hh2/smartbeacon.html
 
The brain wizards that came up with APRS also provided for something called "smart beaconing". It senses when you are turning from GPS data and sends out a position report. You control the turn parameters that trigger the position report to fire. That is how it tracks the turns well on the web interface.

It really is pretty cool stuff, tailored nicely to what we want to use it for.

In case some are wondering about the Technician license needed to operate an APRS rig, I bought the Gorden West tech study guide last evening and read it all the way through. There is an exam pool of 392 multiple choice questions, all of which are word for word in the study guide. Today I took three sample tests online and scored 90 or above on all of them (passing grade is 74). This is no proof of any particular prowess on my part, just an indication that many aircraft builders already have a decent grip on a lot of the information needed to pass the exam. The exam is a selection of 35 questions from the pool.

I'm looking forward to getting the ticket and putting an APRS rig in my RV-6.
 
I concur Sam, anybody with the fortitude to build an RV can get their No Code Tech License without too much trouble. "No Code" means no morse code, it's not required anymore.

I'll tell you this, if Steve Fossett had had one of these on his aircraft beaconing every minute, he wouldn't be missing today...
:(
 
I concur Sam, anybody with the fortitude to build an RV can get their No Code Tech License without too much trouble. "No Code" means no morse code, it's not required anymore.

I'll tell you this, if Steve Fossett had had one of these on his aircraft beaconing every minute, he wouldn't be missing today...
:(

I just saw on the news that Steve Fossett has been declared dead.
 
APRS isn't perfect

I hate to be a kill-joy but...

I did a little experiment with APRS during a trip from North Dakota to LOE. I got about three hits that eventually made it to the internet. If there isn't a ground station anywhere near you, it doesn't do much good.

Frequency congestion isn't your friend either. There's a very good chance that your data packet will be stepped on by someone else in a congested area. If everyone transmits more frequently to get through, it just gets worse.

There are a couple of amateur satellites in low earth orbit that can relay APRS packets, but unless you're at the north or south pole, you're only going to see one a couple of times a day.

Paige
RV-8A
 
I hate to be a kill-joy but...

I did a little experiment with APRS during a trip from North Dakota to LOE. I got about three hits that eventually made it to the internet. If there isn't a ground station anywhere near you, it doesn't do much good.

Frequency congestion isn't your friend either. There's a very good chance that your data packet will be stepped on by someone else in a congested area. If everyone transmits more frequently to get through, it just gets worse.

There are a couple of amateur satellites in low earth orbit that can relay APRS packets, but unless you're at the north or south pole, you're only going to see one a couple of times a day.

Paige
RV-8A

Guess that's why it's called "Amateur Radio". :)

Some of the reading I've done suggested that congestion and coverage can be a problem in some areas, but the technology is so promising I think I'm gonna try it. Time will tell..........

If I can get good results within a 100 miles of the home 'drone, that will cover most of my flying. I'll feel better launching with no destination in mind if I know the spouse can look at the monitor and have a good idea of where to send the search party. Just a two or three county area would be really difficult to work with if nobody knew which direction we were headed.
 
You got it, Sam. It's never intended to be a replacement for an ELT or PLB. It's simply there for fun. Just some of the data is actually helpful besides fun.

My kit should be here soon. :cool:

Phil - N5QCN
 
North Dakota

Hi Paige,

I wondered about the Dakotas. When we flew over to go to Montana last year, there is a whole lot of nothing but beautiful land out there. We might need to fund some remote digipeaters......

We get what we pay for. I've got good Coverage in Minne and on the way to both grandmas - that is 90% of my flying.

Maybe a better antenna or a few more watts would get the signal out? I'm still learning - it is fun.

I plan to launch at 10:30 tomorrow CT for some chili at Aitkin. Let me know if anybody watches.
 
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Sam Coverage

Sam,

Looks like you should have decent coverage near Athens. I was able to hit repeaters 60-130 miles out from 4000ftAGL. Here is a map of some of the repeaters in your area.

Proof will be in the puddin' but it looks promising! There is activity on the the ground, so coverge might be decent from the air.

I like "Howell Hill" near the top of the map.;)
2003408521911754489_rs.jpg
 
Sam,

Looks like you should have decent coverage near Athens. I was able to hit repeaters 60-130 miles out from 4000ftAGL. Here is a map of some of the repeaters in your area.

Proof will be in the puddin' but it looks promising! There is activity on the the ground, so coverge might be decent from the air.

I like "Howell Hill" near the top of the map.;)
2003408521911754489_rs.jpg


Thanks Pete!

Looks like Howell Hill is just a little north of Lick Skillet and west of Bell Buckle (I'm serious!). When I get the rig running I'll circle Howell Hill with a series of pings for you. :)

I'm gonna get a kit on the way so maybe all the bits and pieces will be in place when I catch up with an exam crew. Looks like I will try the 300mw unit with a whip antenna to see how that works, if needed I can add the 8w amp. I really considered using a handheld radio but like the idea of an embedded system in the plane that doesn't require any attention other than flipping a switch.

I'm assuming the WX icons on the map are the "weatherbugs" that some of the TV stations have scattered around the area?
 
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Local coverage is easy

APRS for local use is possible anywhere. It's really pretty easy to setup your own digi / gateway. All you need is an old computer with an internet connection, sound card, and 2m radio. Heck, if you live in a congested area, you could even use a dedicated frequency of your own to avoid the congestion. I guess my point was that if you just install a tracker on 144.39 and expect to have nationwide coverage, it isn't going to happen.

Most of the weather stations you see out there are owned by individuals. Again, easy to setup if you've already got the computer running digi software. You can pickup a basic weather station that will stream data to a serial port for about $100.

As for my experience with North Dakota, we had coverage in Minot, Grand Forks, Bismarck, and Fargo.

Paige
 
I plan to launch at 10:30 tomorrow CT for some chili at Aitkin. Let me know if anybody watches.

Nice flight, Pete! You just landed at ANE, did notice you were a little low on final and you might want to concentrate on holding the center line of the runway a little tighter. :D

Looks like the only significant dropouts were up around AIT, guess the digi-peater population is a little sparse up there.

I noticed the stiff headwind you had on the return leg. One of the WX stations on your route was showing gusts nearly at 20kts in your face.

This is really cool stuff and I suspect as more RVers find out about it this may become a popular addition to our planes. Thanks for bringing this to the attention of the forum and we look forward to following each other around virtually!

Hope you enjoyed the chili (oh....that is why you were slower coming back....)!
 
Chili at Aitkin!

Hi Sam,

Snow plowing was a bit better left of the centerline:D

There was fun headwind on the way back, but up at 3500ft is was pretty smooth. Alex P was down lower and had less wind in the face, but it was bumpy. As Alex said, "you pick your poison".

Good Chili - very spicy and some good company. We had lunch with Dale Field in his RV-6A and nice gentleman from Lake Elmo in a Tailwind.

2004262079550840070_rs.jpg


Probably 25-30 planes in all - many on skis, they had groomed snow runway. Snapped this pic of a Beaver departing:

2004200577790715475_rs.jpg


Whole city of ice fishing Houses on Mille Lacs:

2004218564110250485_rs.jpg


The tracker captured much of the action:

2001650631105031332_rs.jpg
 
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I wondered what you were doing with that little circle around Hennipin Island.

That was really neat. I did the Google Earth view, too.
 
Hello,

I have been getting lots of questions on where to take your HAM Exam. Here is a quick way to find out:

http://www.arrl.org/arrlvec/examsearch.phtml

If you can build a plane, you can pass this test with a bit of study.

Pete, a check with a local ham or club might also be beneficial. I found several local exams that aren't listed on the ARRL site.

A Micro-Trak 300 has been ordered (update: shipped today!) and hopefully installation in the plane should commence in a few days!
 
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A Micro-Trak 300 has been ordered (update: shipped today!) and hopefully installation in the plane should commence in a few days!

Hey Pete,

The Micro-Trak arrived today and I'm poking through the set-up software. Could you upload a screen shot of your configuation page? I'm sure it would be helpful not only for me but others who will be setting up their Micro-Traks soon. You have a great config and I don't see any point in reinventing the wheel. :)

The turn slope is the main thing I'm not too sure about, but all your settings for SmartBeaconing would be interesting to see.

Thanks,
 
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Sure Thing

This file works for me:

2000746599171202300_rs.jpg


Look for me and the younger daughter (my best aviator) on the way to Nana's for lunch tomorrow.

2004307977364305801_rs.jpg


Fog in Iowa - new flight - Circles over the frozen river, Gas at SGS, and then off to local lunch......

2002481101532122976_rs.jpg
 
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This file one works for me:

2000746599171202300_rs.jpg

Thanks Pete. I'm still not clear on the definition of turn slope but I'll use the 255 you have since your SmartBeacon seems to work fine. I set low speed to 55 @120 sec and high speed to 56 @ 60 sec.

I plan to take the exam in a week so we should see how the new toys work soon. I have the Byonics whip antenna that can be used for testing.

You and the kid have a great flight and we'll be watching. :)
 
Smart Beaconing

SmartBeaconing is an algorithm created by Steve Bragg for adjusting the transmit rate by the speed and heading changes on the tracker. As the tracker moves faster, the transmit rate will increase linearly. SmartBeaconing also uses CornerPegging to cause transmissions to occur when the tracker turns corners. In order to use SmartBeaconing, the GPS must send speed and heading information with the GPRMC sentence.

The SmartBeaconing algorithm works like this:

IF (speed < slow_speed) // "Stop" threshold

beacon_rate = slow_rate;

ELSE { // We're moving; adjust beacon rate to speed, and peg corners

turn_threshold = min_turn_angle + turn_slope / speed; // adjust turn threshold according to speed

IF (heading_change_since_beacon > turn_threshold) AND (secs_since_beacon > min_turn_time)

CornerPeg = TRUE; // Corner pegging

IF (speed > fast_speed) // Adjust beacon rate according to speed

beacon_rate = fast_rate;

ELSE

beacon_rate = fast_rate * fast_speed / speed;

}

if ((secs_since_beacon > beacon_rate) OR CornerPeg)

// ... send beacon

--
Michael
 
Which NMO mount did you use?

I also bought a "stealth Antenna" ( http://cgi.ebay.com/Phantom-Antenna...210679586QQihZ017QQcategoryZ296QQcmdZViewItem ) and mounted it on the bottom of the airplane.


I am not familiar with the mount type on these antennas. It looks like you have to buy an NMO style mount. Obviously the magnet styled NMO mounts I saw won't work for our applications. Can you point me in the right direction for the type of mount, or source of your mount, that you used with the stealth antenna. I like this option, then I can just feed it directly off my panel mount gps and don't have to buy another gps to put in the wing tip.
 
enielsen,

That is exactly the mount I used. When I ordered my antenna I had the option of also ordering the mount for $10 or $15 more. I did this and it included enough coax to easily make it to my tracker box mounted behind the seat.

--
Michael

p.s. Just looked back at the EBAY auction and the NMO mount was $10 more.
 
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