# Best Trackers/Altimeters for High Altitudes

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#### Buddy Michaelson

##### Well-Known Member
I’m currently working on a Class 3 project for Balls next year, which should reach an altitude of around 250,000ft if all goes as planned. I have some questions on the best trackers and altimeters available that are somewhat cheap. The only high altitude trackers that I have found to work over 150,000ft are Kate and Aim Xtra, both nice systems but the I’m scared to use the Aim with not as many systems out there and really no history of high altitudes. As well, I do not have a windows computer, by the time I’m done with it, it’s probably be more than the Multitronix Tracker. I very much trust Kate, as the altitude is unlocked on his system, and giving the data and coordinates real time is a nice feature, is there any other trackers that’ll work at these altitudes? As far as the Altimeters go, I plan on using atleast 3-4, and a couple of timers if I can find some. The ones I am looking at are Raven and Marsa, they seam to be the most trusted, by far not cheap at all, but these are the only ones that I can find that are reliable, I Mn thinking about having a timer in each charge, and guessing the exact time it takes for the rocket to burn out and cost, than return back, luckily with not much air, I will have some play in that, as an ultimate backup.

#### plugger

##### Well-Known Member
Oh boy. There's so much to unpack here.

I’m currently working on a Class 3 project for Balls next year, which should reach an altitude of around 250,000ft if all goes as planned. I have some questions on the best trackers and altimeters available that are somewhat cheap. The only high altitude trackers that I have found to work over 150,000ft are Kate and Aim Xtra, both nice systems but the I’m scared to use the Aim with not as many systems out there and really no history of high altitudes. As well, I do not have a windows computer, by the time I’m done with it, it’s probably be more than the Multitronix Tracker.
VMware Fusion has USB pass through assuming you're on MacOS. There are options on Linux as well. You don't have to buy a new computer to run Windows.

As far as the Altimeters go, I plan on using atleast 3-4, and a couple of timers if I can find some. The ones I am looking at are Raven and Marsa, they seam to be the most trusted, by far not cheap at all, but these are the only ones that I can find that are reliable, I Mn thinking about having a timer in each charge, and guessing the exact time it takes for the rocket to burn out and cost, than return back, luckily with not much air, I will have some play in that, as an ultimate backup.
I can't speak to the Marsa as I've not used one but if you're considering a Raven you should order one from Adrian with the High Alt firmware. Otherwise you won't be able to configure timer values that would be useful in a project that would go that high as the default Raven can only have a TVal less than or equal to 51.2 seconds. You should also consider some logic more than just a simple timer in case an anomaly occurs. A AltusMetrum *Mega would be a good candidate here too as it has tilt inhibit capabilities and very flexible programming options. But realistically Kate 2.0 is the one stop shop for what you're after so if you can afford it that would be the best route. What you should most likely not do is use a couple of simple timers.

#### Cameron Anderson

##### Well-Known Member
There are many accelerometer-gated timers so you wouldn't need to guess on such precise timing events. Raven and Marsa both have gated timing, I've use both and like both.

AIM XTRA claims 100 kilometer tracking range. I have a 2.0 system and I'm testing it tomorrow for the first time (current version is 3.0, I'm unaware of the differences) to 7,000', but so far I love the interface.

#### plugger

##### Well-Known Member
AIM XTRA claims 100 kilometer tracking range.
But does that mean the GPS will still be able to acquire a lock above 50km?

#### Cameron Anderson

##### Well-Known Member
That I don't know, but honestly, I wouldn't be surprised. I'm planning on chipping away at its capacity at BALLS next year to 15 kilometers.

#### ksaves2

I’ve been out of the loop for awhile but I remember the best COTS (commercial off the shelf) GPS I read could do 150k. That said, the speed limitation is an issue.
Surpass the 1000 knot limit and the reporting goes quiet. Some units do either/or which means no matter how slow you are going the system locks out at 59,000 feet or it’s one or the other. Meaning if one's device is running less than 1000 knots the altitude limit can be breached. It depends upon the GPS chipset one is using.
The high altitude balloon fliers used to be well versed as to what GPS could be flown high but that sport is not as popular as it once was. Of course, helium or hydrogen balloons don’t go fast but I’ve seen APRS reported altitudes in the 125k range.
If the Multitronix Kate (I think her voice is Open Source) or the AIM Extra have been reported to work above 150k then that would be the way to go.

Otherwise, you might get one or two positions on ascent with a long “quiet” period until the rocket descends below 150k. Go with what others report work at the altitudes you require. Range and altitude are two different characteristics.

Kurt

featherweightaltimeters.com has a tracker claiming 300k feet range. A tracker system + 1 Raven comes to around $510. Didn't the rules change at BALLS for multi-stage rockets where a tilt limit lockout is now required? AFAIK that means either Kate2 or one of the megas from Altus Metrum. #### Cameron Anderson ##### Well-Known Member featherweightaltimeters.com has a tracker claiming 300k feet range. A tracker system + 1 Raven comes to around$510.

Didn't the rules change at BALLS for multi-stage rockets where a tilt limit lockout is now required? AFAIK that means either Kate2 or one of the megas from Altus Metrum.
Not sure about the tilt requirement at BALLS...my M to L two-stage used a tilt measurement (Marsa33 with tilt gadget) but no one said it was a requirement to fly. Maybe the tilt lockout is a class III requirement. AIM XTRA also has tilt measurement and lockout capability.

And there was 2 telemegas on-board Kip's O to N cruise missile, so...

#### ksaves2

featherweightaltimeters.com has a tracker claiming 300k feet range. A tracker system + 1 Raven comes to around \$510.

Didn't the rules change at BALLS for multi-stage rockets where a tilt limit lockout is now required? AFAIK that means either Kate2 or one of the megas from Altus Metrum.
Remember, Range at altitude and ability to report GPS altitude live are two different balls of wax. Once a tracker is down on the ground, especially on the salt laden playa, the ground footprint is drastically small. The reason is that the salts have a tendency to absorb Rf energy. I admit I’ve never been out there (maybe someday) but folks who’ve tried to use GMRS radios say they don’t go very far and RDF tracking is an extremely dicey situation.

In that situation, a higher powered GPS tracker will be very helpful (or something on the 2 meter or 70cm Ham bands). Receive a last known position packet close to the ground 5 miles away 100 feet in the air and one is likely going to be able to get to that position and have joy getting their project back or dig the fincan out of the ground!! Kurt Savegnago

#### Cameron Anderson

##### Well-Known Member
Remember, Range at altitude and ability to report GPS altitude live are two different balls of wax. Once a tracker is down on the ground, especially on the salt laden playa, the ground footprint is drastically small. The reason is that the salts have a tendency to absorb Rf energy. I admit I’ve never been out there (maybe someday) but folks who’ve tried to use GMRS radios say they don’t go very far and RDF tracking is an extremely dicey situation.

In that situation, a higher powered GPS tracker will be very helpful (or something on the 2 meter or 70cm Ham bands). Receive a last known position packet close to the ground 5 miles away 100 feet in the air and one is likely going to be able to get to that position and have joy getting their project back or dig the fincan out of the ground!! Kurt Savegnago
I was getting on-ground live position feeds on my 900mhz T3 from a mile away without an issue, but yes, in-air range is not the same as on-ground.

Also, I think featherweight has point of impact prediction (I haven't used the system but I recall seeing that).