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keithp

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telemini-v3.0-top-640.jpg

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TeleMini v3 is a major upgrade to our TeleMini v1 product. TeleMini remains the worlds smallest dual-deploy altimeter with built-in telemetry and radio beacon for tracking.
  • Recording altimeter for model rocketry
  • Supports dual deployment (can fire 2 ejection charges)
  • 70cm ham-band transceiver for telemetry downlink and radio direction finding
  • Barometric pressure sensor good to 100k feet MSL
  • Uses a single LiPo rechargeable battery
  • 512kB flight data storage
  • 1.7 x 0.5 inch board designed to fit inside 18mm airframe coupler tube

https://altusmetrum.org/TeleMini

These are available today from our web store

https://shop.gag.com/flight-computers/telemini-v3.html

AltOS 1.7 includes firmware and software updates to support TeleMini v3. The new computer software is available at

https://altusmetrum.org/AltOS

A new version of the AltosDroid application is available in the Google Play Store.
 
After having read up on all the GPS and Rf options out there for tracking rockets and confusing myself to no end, can someone explain to me in non-technical terms if this telemini is an out of the box ready solution for rocket locating with the Android app or is more hardware required?
 
After having read up on all the GPS and Rf options out there for tracking rockets and confusing myself to no end, can someone explain to me in non-technical terms if this telemini is an out of the box ready solution for rocket locating with the Android app or is more hardware required?

RDF tracker on I believe the 70cm ham band. You likely need a Ham license and an appropriate receiver, attenuator and Yagi antenna to track properly.
Not a GPS tracker but the trade off is you don't have to carry the extra weight of the GPS receiver in the rocket but you don't get the accuracy of a telemetered GPS position.

I wouldn't recommend using this to go out on the playa out west to try to break a record unless one is willing to risk losing the whole shebang. The subsurface salts in the lakebed soak up Rf like a sponge so once the rocket is down, the ground footprint of the tracker is very short range. O.K. when at altitude but once
it's down, unless one can hold a tight bearing track to the rocket it will be very hard to home in. I've never been out there but have seen postings that
many consider GPS mandatory for some really extreme flights on the playa. On Midwest farmland it will perform better. Kurt
 
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After having read up on all the GPS and Rf options out there for tracking rockets and confusing myself to no end, can someone explain to me in non-technical terms if this telemini is an out of the box ready solution for rocket locating with the Android app or is more hardware required?

As Kurt says, TeleMini provides a simple radio beacon which can be used, in conjunction with a 70cm amateur receiver, for Radio Direction Finding (RDF). This involves using a directional antenna and signal strength measurements to estimate the direction from the receiver to the beacon. With practice, this is a fine way of locating your rocket. It is not as easy as using a GPS-based tracker, like our TeleMega, TeleMetrum or TeleGPS devices. We're still working on how we might be able to create a GPS-enabled tracker in this tiny size.

TeleMini also provides telemetry data which can be received with our TeleBT or TeleDongle products connected to a laptop or android device so that you can track the state of the rocket (speed, acceleration and height). You can also use one of those devices to download flight data as TeleMini doesn't have a USB connector on the board.
 
Agree it's a good way to find a rocket and folks have been doing that for years before GPS tracking was viable. RDF is extremely helpful with rockets that land a fair distance away but
one gets a "visual" at the limits of vision just before touchdown. At least there is a visual bearing augmented by the tracker as to how to proceed. Locking a bearing on a completely sight
unseen flight takes practice and the goal is getting within the ground footprint of the tracker to pick up a signal to home in on. If there is a tracker failure in flight, one can be out of luck
if a visual is not seen on descent.

If going with a completely sight unseen rocket flight, an edge can be had if one sims the heck out of the intended flight and note the total flight times. Get a list of the times and
use a stop watch when the launch button is pushed. The elapsed time can give some empiric idea of the flight events, although it seems the Tele-Mini can telemeter that info to make it even
easier. When it's expected that the rocket should be getting lower, that's the time to really concentrate on getting a good bearing and lock it in before the signal is lost.
I think an electronic attenuator is smoother in that regard as opposed to a mechanical one.

One other thing to optimize the final fix is to use a handheld mapping GPS that in Garmin parlance is "Sight n' Go". One can sight a distant object and lock a bearing "to" that object
to maintain the bearing. This is great for modrocs one sees landing at a distance that perhaps end up in tall grass. Sight it up and lock it in before touchdown. Just keep walking that line and there's a good chance it will get you close. Now if it's completely sight unseen with an RDF rocket, one can hold the mapping GPS parallel to the Yagi beam and once the signal is lost, lock the bearing. They now have a line they can walk under auspices of their GPS that will greatly increase one's chances of getting within the ground footprint of the tracker and not experience randomly getting off course.

The thing to do would be to have the mapping GPS at the "Sight n' Go" screen readied before the flight. Once in flight, if it appears that there is no visual to be had, whip out the Garmin have it parallel to the Yagi beam, ready to get a lock once the signal is lost. I have an Etrex Vista HC I can wear with a lanyard around
my neck at the ready for that purpose.

Remember, the goal is to get that sucker back in time to fly the next one. Kurt
 
I wouldn't recommend using this to go out on the playa out west to try to break a record unless one is willing to risk losing the whole shebang. The subsurface salts in the lakebed soak up Rf like a sponge so once the rocket is down, the ground footprint of the tracker is very short range.
People keep saying this but I didn't have any problem at all finding stuff at Black Rock with Com-Spec RDF the two times I've been. Maybe it's a problem with 70cm, I've never used it.
 
People keep saying this but I didn't have any problem at all finding stuff at Black Rock with Com-Spec RDF the two times I've been. Maybe it's a problem with 70cm, I've never used it.

Did you get a visual on descent or were both flights completely sight unseen? Getting a visual on descent makes a world of difference. If you have the older Com-Spec trackers on 218Mhz, they put out 50mW on the 1.25 meter band and might have different propagation issues. The folks who have trouble are those where they have absolutely no visual on the rocket and have difficulty maintaining a bearing to get within the diminished ground footprint. Yes the frequency might make a difference.

Com-Spec was slammed by the FCC as "animal trackers" are supposed to top out at 30mW max. That's why you don't see the 50mW ones anymore. Get a Ham license and one
can do whatever they want as long as their rocket can sling up the heavier batteries for higher powered trackers and the trackers don't dork their deployment electronics. Kurt
 
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Does it record/store more than one flight?

s6

Yup, it's got 512kB of storage now, so it works just like our other flight computers and can hold several flights. It also logs a lot more data, including battery and pyro voltages.
 
Completely sight unseen, typical ranges a couple of miles.

Nice. Did the rockets generally touch down out in the open or were they hidden by ground cover? If you have a good setup that serves you well keep it up.
Ooooops, I made a mistake. The PT-2B tracker https://www.com-spec.com/law_enforcement/manual/PT-2B_LPRS_Trans_Manual.pdf was 95mW output and the AT-2b 50mW: https://www.com-spec.com/rocket/manual/at_2b_transmitter_manual.pdf Seems like the PT-2b was for law enforcement.

Higher power output can overcome some deficiencies. Thing is the only trackers offered now are lower powered now. Kurt
 
Nice. Did the rockets generally touch down out in the open or were they hidden by ground cover?
Ground cover? Have you ever been to Black Rock? :) No, in the open.

Not to derail this thread too much, but obviously not all RDF is created equal. The Com-spec, while pricey, is fairly high-power, operating on a favorable frequency with the best modulation (CW) for easy detection, and with a receiver that's optimized for doing that one thing. It's pretty much inevitable that it will perform better than a 70cm system using a general-purpose radio. I suspect a lot of reported RDF problems are due to cheap receivers or antennas or bad configuration. All I can say is that I have used the Com-spec a bunch of times on playa and encountered no problems so far from magical radio-sucking dirt. YMMV.
 
That's good to know but the high power Com-Spec stuff is no longer available and one is stuck with 30mW tops. Fly one of those then report if there are any changes noted. Kurt
 
So TeleMini works like my TeleMetrum but without GPS? So I'd receive audio and textual reports via TeleBT and my Android phone, but the reports would not include any info about the rocket's bearing and distance from the pad? Tough decision, I love my TeleMetrum, GPS is sweet, but TeleMini is half the price.
 
So TeleMini works like my TeleMetrum but without GPS? So I'd receive audio and textual reports via TeleBT and my Android phone, but the reports would not include any info about the rocket's bearing and distance from the pad? Tough decision, I love my TeleMetrum, GPS is sweet, but TeleMini is half the price.

One gains a smaller size and weight I believe. Kurt
 
So TeleMini works like my TeleMetrum but without GPS? So I'd receive audio and textual reports via TeleBT and my Android phone, but the reports would not include any info about the rocket's bearing and distance from the pad?

Exactly. You get altitude, speed and acceleration data along with battery and pyro charge status, but you don't get any position information. You also don't get an accelerometer, so the data recorded is not really useful for figuring out max speed or acceleration values. The goal is really to offer a dual-deploy flight computer with integrated direction finding in the smallest possible package. I'm building a 24mm min-diameter airframe to fly on CTI pro-24 motors where I'll need apogee deploy and some way to find the rocket after it leaves the pad.

With practice, RDF is an effective technique for locating rockets. All of our transmitters include an RDF beacon tone as it works with weaker signals than GPS solutions, and so provides a nice backup in case something happens during flight. Some people even seem to like the challenge.
 
Keith, you should post a picture that is "actual size". I think some folks aren't quite getting just how tiny this thing is.

And for those of you who don't know.....dual deployment and RF tracking together in this tiny a package (not to mention that it works very well) is incredible. Want to build a 24mm or even 18mm minimum diameter rocket that's fully optimized to set/break altitude records (and that you want to recover)? - you NEED this thing. The original version was awesome and VERY unique....now it's even better.

I wish I was still flying.....I'd be the first in line for one of these.

Way to go Keith,
s6
 
Keith, you should post a picture that is "actual size". I think some folks aren't quite getting just how tiny this thing is.

Sure, here's something to compare it to -- an Estes B6 motor (18mm). TeleMini slips into the same tubing as that motor.

IMG_20170426_185658.jpg
 
That's good to know but the high power Com-Spec stuff is no longer available and one is stuck with 30mW tops.
They went from 50 mW to 30 mW, which theoretically will reduce range by a factor of about 0.85. (Remember to get twice the range you have to increase power by 4x so it's not as much of a reduction as might initially seem.) That said, I haven't used the new lower-power transmitter.
 
They went from 50 mW to 30 mW, which theoretically will reduce range by a factor of about 0.85. (Remember to get twice the range you have to increase power by 4x so it's not as much of a reduction as might initially seem.) That said, I haven't used the new lower-power transmitter.

What dinged Com-Spec is it's in the FCC rules that the highest powered "wildlife tracker" allowed is 30mW so it took quite some time for the law to catch up to them. That said, they did have a 95mW RDF tracker available for law enforcement on that same band.

Take good care of your AT-2B because if you wreck it, there's no replacing it or getting it repaired from Com-Spec. Since the FCC caught up with them, they'll
likely say they are out of parts and won't repair any of the older trackers. One's only recourse would be to buy used from someone else.

I did purchase one from them some years ago on the 1.25M Ham Band I believe 222.130Mhz and it transmits my callsign every 10 minutes in Morse code along
with the usual beeping. My TH-F6A all mode H/T seems to receive it well but I've never flown it. I will likely have it ride along someday as a backup for
a GPS tracker. Kurt
 
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What dinged Com-Spec is it's in the FCC rules that the highest powered "wildlife tracker" allowed is 30mW so it took quite some time for the law to catch up to them.
Do you know for sure that FCC is what caused them to quit offering the AT-2B? They moved off the wildlife bands in about 2007 due to an FCC filing, and the 50 mW AT-2B has always required a ham license. I don't know what's caused them to quit making the AT-2B, but I have no reason to think that the 30 MHz RC-HP will do much worse in normal use. Note that the RC-HP also still requires a ham license.

Fortunately the AT-2B is very robust. I've crashed several and the repair is often as easy as soldering the antenna back on or maybe replacing one of the external capacitors. Most of it is potted in some kind of encapsulant.
 
Do you know for sure that FCC is what caused them to quit offering the AT-2B? They moved off the wildlife bands in about 2007 due to an FCC filing, and the 50 mW AT-2B has always required a ham license. I don't know what's caused them to quit making the AT-2B, but I have no reason to think that the 30 MHz RC-HP will do much worse in normal use. Note that the RC-HP also still requires a ham license.

Fortunately the AT-2B is very robust. I've crashed several and the repair is often as easy as soldering the antenna back on or maybe replacing one of the external capacitors. Most of it is potted in some kind of encapsulant.

Yup, It's true. I looked up the FCC rules someone posted in another thread here and officially 30mW is the limit. If one goes to the Com-Spec site and the R/C aircraft tracker offerings
https://www.com-spec.com/rcplane/index.html the highest powered tracker is 30mW and the frequencies are actually in the 1.25M Ham Band. It appears they are no longer offering
the "Wildlife Tracking" devices to anyone except researchers.

Here is a link to a PDF that explains it: https://www.aphis.usda.gov/wildlife_damage/nwrc/publications/83pubs/kolz831.pdf

An easy Ham Radio Tech license will get one legal access to the ham bands and they can learn something along the way too. Kurt
 
How does one configure a Telemini V3? I’ve downloaded and installed AltOS1.7 and no bueno.
 
Keith, you should post a picture that is "actual size". I think some folks aren't quite getting just how tiny this thing is.

And for those of you who don't know.....dual deployment and RF tracking together in this tiny a package (not to mention that it works very well) is incredible. Want to build a 24mm or even 18mm minimum diameter rocket that's fully optimized to set/break altitude records (and that you want to recover)? - you NEED this thing. The original version was awesome and VERY unique....now it's even better.

I wish I was still flying.....I'd be the first in line for one of these.

Way to go Keith,
s6

I have a 24mm MD rocket, this device fits in a custom nosecone easily. Using it with very sparse directions just pisses me off. The TeleGPS has better directions.
 
Using it with very sparse directions just pisses me off. The TeleGPS has better directions.

The TeleMini directions and TeleGPS directions are both contained in the AltOS manual. It's the same document. The directions are different as the process is different, but they're no better or worse in comparison imo.
 
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