$40 (US source) GPS tracker

Hobby cross-pollination. Found this from recent R/C plane/quadcopter forum posts.

3G sim card support to use AT&T or T-Mobile. 27 grams. With T-mobile, $10 fill card with data plan activated is good for 90 days. Refill account as needed. Very loud location beeper, activated with a call to the device. Very long battery life. True GPS. Apparently, the best unit around right now.

Tech details:

https://blog.sam-thompson.info/rf-v16-gps-tracker-guide/

Video reviews:

[video=youtube;VMrM2F1-xRI]https://www.youtube.com/watch?v=VMrM2F1-xRI[/video]

[video=youtube;cyf6FJlK7DM]https://www.youtube.com/watch?v=cyf6FJlK7DM[/video]

US source: (actually cheaper than Chinese sources; haven't bought yet from this seller, so I can't vouch for them, but feedback seems good)

https://www.ebay.com/itm/Brand-New-...250?pt=LH_DefaultDomain_0&hash=item27fb1d80b2

Recent comments at the blog linked to above are included below. This isn't good for 2G dependent GPS trackers in general. I haven't seen this caveat mentioned elsewhere in the R/C forums, not to say it isn't there. My on-line search for 2G sunset gives a completion date of Jan. 2017. T-Mobile's plan sounds like they may leave some 2G capability behind, just at a lower overall network bandwidth, but that would most likely be for towers near heavy population density areas, not necessarily near your launch site:

https://gigaom.com/2012/02/23/t-mobile-pounds-the-first-nail-in-2gs-coffin/

"T-Mobile plans to sunset between two-thirds and three-quarters of its GSM channels in the PCS bands leaving, only a modicum of 2G bandwidth left for older phones that don’t sport 3G or 4G radios and to support basic data services for its machine-to-machine communications business."

Comments from blog:

Marc • 12 days ago
Will the 2G sunset affect the v16? All carriers are phasing out 2G or have. They say it will accept a 3G or 4g sim but only communicates on 2g. Will the v16 become obsolete the very near future?
Thanks

Sam Mod Marc • 9 days ago
Hi Marc, how soon is the very near future? Do you have a reference for this info? I believe the RF-V16 requires only GPRS at a minimum, and still works fine over 3G and 4G. Is GPRS going away?

Marc Sam • 9 days ago
2g is being phased out by AT&T, not sure about T-Mobile or GPRS. Do you have an RF-V16? I would like to get one but read you should get data. I was in a T-Mobile store and he said the $10 prepaid card does not include data. I ordered a Marco Polo tracker, it's only 12 grams so I could also use a RF-V16 but don't want to spend more than the $3.00 per month. Any further input on people with experience with the RF-V16 would be great.

Sam Mod Marc • 6 days ago
Hi Marc, yes I own an RF-V16, I'm the author of this blog You can read more about it above, and we'd like to hear your experience with the Marco Polo tracker please!

Marc Sam • 5 days ago
Here is the latest daily rate plan off of the T-Mobile web site.

Pay As You Go

Recurring monthly fee of $3 per month.
You get a combined total of 30 minutes of calls or text messages per month.
Additional outgoing/incoming calls or texts are $0.10 each.
Includes nationwide roaming and nationwide long distance while on the T-Mobile network.
You can also add optional data passes:
1-day 500 MB data pass for $5
1-week 1 GB data pass for $10
(this pass is good for 7 days)

This gets expensive quick, any ideas?

Marc

Marc Sam • 6 days ago
Hi Sam,
Be glad to report back on the Marcp Polo when I have some tests done. I'm a little paranoid I guess of loosing my Phantom Vision so I would like to have some redundancy. I've read the entire blog and comments and I want to say thanks as this is helpful to a lot of us. Could you provide some clarification please as I would also like to have an RF-V16. I'd also prefer to keep my recurring monthly costs to a minimum. My original thoughts based on my research findings was that all I needed was a T-Mobile sim and activate it and put a $10 prepaid card / pay as you go plan. $3.00 was the minimum fee that would be deducted from the card per month. In talking with a T-Mobile store associate that plan does not include data which it sounds like you need for true gps tracking. This is where I get a bit confused, what plan do I need to get the gps to work? Other sites have said the $10 prepaid would work but based on what I've read here and some other places data is required. I would love specifics and the best cost effective plan to go with that is guaranteed to give true gps tracking so I know what I'm up against. Also back to my 1st concern the 2G sunset, on another forum a person wrote in that they bought one and couldn't use it because it only supported 2G. So you see the more research I do the more confused I get. Thanks for your help.
Marc

Looks like a great option, I wonder will it still get GPS lock while inside the rocket?

As long as you have cell coverage from the appropriate service in your launch area, one should be O.K. Keep that in mind. Look at the coverage maps of the provider before investing. A rocket lying on the ground might not hit a tower so well. For all the rest, a self contained system is the best bet and once one buys it, there are no monthly costs. Find one rocket with the system with two to three hundred dollars of hardware tied up in it and the tracker can almost pay for itself. Have two or three flights where you don't see anything but an icon on a map or a signal blip on a signal strength meter and the system has most definitely paid for itself. If one fails to research the cell phone tracker, they might have a rude awakening when they can't get a fix after the rocket has landed plus the issue of "maintaining" the account during the off season if there is one. You let it lapse and want to fly on a whim, how fast can service be re-established? Kurt

I think it was mentioned in other threads that not all launch sites have good cell coverage from any providers. For example you wouldn't use this in Black Rock.

ksaves2 said:

As long as you have cell coverage from the appropriate service in your launch area, one should be O.K. Keep that in mind.

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Yes, you should still be able to get the lat/lon text message with basic service even after 2G networks disappear. However, from that blog:

"The GPS chip utilizes GPRS and Assisted GPS, in order to expedite the process of obtaining satellite information. For this very reason, it is important that your SIM card includes a data plan. My device was only able to provide an inaccurate LBS position until I enabled data on my SIM card, at which point it became nicely accurate."

Elsewhere, I see that Assisted GPS just allows finding the satellites much more quickly possibly meaning that without the assist you might have to wait quite a while after landing for the GPS module to slowly locate itself, but you'd get an accurate fix via text message once it did. I'm not sure.

Look at the coverage maps of the provider before investing.

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AT&T and T-Mobile only (GSM service) or any 3rd party carrier who uses their networks; for instance, "TracFone is a huge pre-paid carrier with MVNO agreements with all four major American carriers; AT&T, T-Mobile, Verizon Wireless, and Sprint." Also, see if anyone at your launch site uses AT&T or T-Mobile and see how good their received signal strength is.

plus the issue of "maintaining" the account during the off season if there is one. You let it lapse and want to fly on a whim, how fast can service be re-established?

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$10 every 90 days to keep the account active, so $40/yr. If the calling card fill is allowed to expire, I've found via on-line search that there's usually a 12 month grace period before the phone's internal SIM card needs to be reactivated. Otherwise, it's just a matter of inputting the data from the new calling card into the phone as usual.

taiwanluthiers said:

I think it was mentioned in other threads that not all launch sites have good cell coverage from any providers. For example you wouldn't use this in Black Rock.

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Absolutely, but if you launch at Black Rock launches, you probably aren't too concerned about how much money you spend on your rocket's electronics.

Hello all.

I purchased a GPS tracker similar to the ones you're discussing in the last couple of weeks and use AT&T's prepaid service with a SIM card (photo of the unit in my photos as I can't get it to insert here).

Ground tests to date (at least 20 of them) all show promising results, the most restrictive being a test where I put the GPS unit on the ground floor stairwell of a 3-story building with metal staircases and platforms/landings on the 2nd and 3rd floors. I called the Go-Fone number I got with the pre-paid cell service, and the unit texts back to me with Lat and Lon coordinates, date and time, and a link to Google Maps that I can use as I would on any device. It gives me Sat or Map view, can plot a course to the dropped pin where the GPS unit sits, and can show me where I am relative to the unit.

My only concern with the unit is its ability to survive actual flight as the instructions expressly say to not shake the unit violently. I'm not sure exactly what "violently" means in their opinion, but I'd suggest that high G rocket flight probably qualifies... :duck:

I'll be at Red Glare this weekend with the SEVRA group from Va Beach, VA. Look for me if you'd like and ask what sort of success I've had with this unit. It will see a crucible of I, J, and K motors Saturday and Sunday.

Sam

SammyD said:

I purchased a GPS tracker similar to the ones you're discussing in the last couple of weeks and use AT&T's prepaid service with a SIM card (photo of the unit in my photos as I can't get it to insert here)... My only concern with the unit is its ability to survive actual flight as the instructions expressly say to not shake the unit violently. I'm not sure exactly what "violently" means in their opinion, but I'd suggest that high G rocket flight probably qualifies...

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What is your unit's model number? The ones made for car tracking might be less able to take a lot of violent shaking. The unit I described here was originally sold as a unit to strap to a child's wrist, so it would have experienced a lot of violent shaking and abuse. They no longer sell it with strap loops for that, so I wonder if it was a matter of realizing that it was far too large to be comfortably worn on a small child's wrist and was therefore typically kept in a backpack anyway OR was done for reasons of stealth to prevent an abductor from seeing it and taking it off OR both.

Winston said:

What is your unit's model number? The ones made for car tracking might be less able to take a lot of violent shaking. The unit I described here was originally sold as a unit to strap to a child's wrist, so it would have experienced a lot of violent shaking and abuse. They no longer sell it with strap loops for that, so I wonder if it was a matter of realizing that it was far too large to be comfortably worn on a small child's wrist and was therefore typically kept in a backpack anyway OR was done for reasons of stealth to prevent an abductor from seeing it and taking it off OR both.

Click to expand...

This is a TK102B (version B) as I recall, but it's a Chinese product with no mention of a manufacturer on the box. I'm not at home right now, so I can't get to it. This is made for car tracking, dog tracking, child tracking, etc, or at least it's advertised in the product literature and on the box. I don't think, however, that when they engineered these little gizmos that they ever considered one might strap it to a missile that could break mach and sustain heavy G-loading.

The other problem is the unit is probably designed to be used in an urban or semi urban setting, and most launch field is out in the sticks with questionable cell service...

I'm on the East Coast, and coverage is good even in most of the sticks around here

Every launch I assist around have good coverage

I think West Coast is a particular problem since the sticks tend to be hundreds of miles from civilization. I had very limited service at Hutto (Edge only)

A very useful thread about the RF-V16 and how to set up and use it:

https://www.rcgroups.com/forums/showthread.php?t=2177391&page=1

Sam, If you would post your results that would be great, I'm looking at it for my L2 flight on a K.

I have use a similar device and it works. You call it and it sends the gps data back.

taiwanluthiers said:

The other problem is the unit is probably designed to be used in an urban or semi urban setting, and most launch field is out in the sticks with questionable cell service...

Click to expand...

That's why I and others have said to check for the availability of that service where you launch.

Will let you know when I have some data from Red Glare - I just arrived at 5:00pm Friday (today). Tomorrow (Saturday) and Sunday will be the test days... Sam

Good, love to know the results! I just bought 2 and won't be able to fly for a month

Ok, here we go: Saturday at Red Glare was like being in a wind tunnel, so MY flying was limited as I'm a lowly L1 flier :-| I did get the GPS Tracker up on 2 flights Saturday however. On Sunday, though it was a PERFECT flying day, it only went up on 2 flights also, my L2 Cert Flight (successful flight and recovery) and a K flight just after. My prep took me longer than I expected, so I only got two additional Tracker flights on Sunday - will update more if we get to fly as scheduled in Chesapeake, VA this Saturday... My data is shown below:

Flight 1 Saturday:
3" rocket with a CTI I242W that boosted at roughly 450mph and 12 Gs. Result: Called the number to my AT&T GoFone account that I call "GPS Tracker". It rung, was answered, I was told that the user's mailbox had not been set up, and the phone hung up ALL AS IT SHOULD - yes, that's the way it's supposed to happen. A second later, I received a text from that same number, GPS Tracker, with a time and date stamp, lat & lon coordinates, and a link to Google Maps that dropped a pin exactly where the rocket was located. This flight, due to the wind and even with a drogue-less apogee event landed about 1/4 mile away... I was able to put a moving blue circle on my location, and as I walked away from the launch area, changes in direction would put me off course as I closed in on the Pin shown on the screen. A quick correction, and I was getting closer and closer to the rocket. The Map Data even showed creeks on Higg's Farm that had names, and they were in the right place!

Flight 2 Saturday:
2.25" rocket with a CTI H-163 that boosted at roughly 425mph and 25 Gs. This flight provided me with data as above when I called the Tracker, but I got something else too. This unit has an "SOS" button on the side of it. When pushed, it sends a "Help Me" text to the phone every three minutes until a command is sent back to it, cancelling the SOS. So, until I read the directions the next morning, the tracker kept sending Help Me texts until I turned it off for the day. Though this was a high G flight, I believe the cause of the command being sent was the button got pushed, not the g-loading on the unit, but more testing will clear that up.

Flight 1 Sunday:
4" rocket with a CTI J-244 that boosted at roughly 418mph and 6.5 Gs. I had cleared the SOS prior to flight, and the Tracker worked as it did above. I called it, it hung up after a brief message, then texted time/date/lat/lon/link to me. Clicking the link, it went to Google Maps and showed me exactly where the rocket was located.

Flight 2 Sunday:
4" rocket with a CTI K-520 that boosted at roughly 685mph and 13.5 Gs. This flight, though it went to 7000', landed about 45ft from the pad it lifted from, but adding the 300' of Min Safe Distance, I could use the GPS to check its data and survival. It worked flawlessly.


All in all, I highly recommend this unit so far. Yes, it's only 4 flights, but they were all successful and the unit suffered no damage whatsoever. I do have it in a spongy, foam block inside the nosecones, and that seems to be more than enough protection. The foam came from a junkyard car and was shaped with a serrated kitchen knife for those that want that detail. There are a couple of caveats I noticed with this unit that some simple modifications and programming address:

First, the SOS button: If there is anything that might push that button during flight, try to get it out of the way. I'm going to epoxy a small shoulder around it to prevent it being activated in any way. Why? See Flight 2 Saturday above. The 2.25" rocket above has a PML 2.25" nosecone on it, and it was a tight fit - I think the nosecone bumped the button in flight or on touchdown.

Second, the On/Off button: Do the same thing for the Power button as the SOS button. They are side-by-side, so it's an easy modification, and you don't want the unit turned off for obvious reasons.

Third, setup/programming: The directions are a direct Chinese to English translation, and it's a bit broken in places, but they are very understandable. The one thing that took me a bit was getting the clock set. They don't tell you that they are basing the "+" and "-" values you need to enter to set your local time on GMT (Greenwich Mean Time). That is the reference though. On the east coast, we are -4 during daylight savings time and -5 during the rest of the year. Do with that what you will, but I like my date and time set correctly. The date set up automatically - I did nothing.

Fourth, and probably the biggest PITA: getting the account password set up: In order to load your account with more $$$ when needed after the initial fill at the AT&T store (I did $25 and was down to $17 after 22 calls and texts back to me before leaving for Red Glare), you need to have a web access password for www.myprepaidrefill.com, an AT&T site. Well, the initial password is the last four numbers of the phone number, BUT to change it, you need to be able to receive a text at that number. The GPS Tracker is not a phone and has no screen nor a keypad. I called AT&T, and after about 10 minutes of them trying to figure out what I was doing with an account and active SIM card but no phone, they explained that I'd need to have that card in a device that could receive a text from AT&T with a temporary password so that I could set up the new/personalized password. NOTE: it's only a 4 digit, numerical password like the last four numbers of the phone number, but this step took the longest to get concluded. Luckily, I have an AT&T iPhone and was able to turn my phone off, put the Tracker SIM card in it, turn it on, and receive a text with the temp password. Once done, swap the SIM card back, and everything else was simple. NOTE: I believe you can put the SIM card in anyone's phone that also uses a SIM card (i.e. a friend's phone) and get this step accomplished.

That's all I've got for now. Like I said above, when I get some more data, I'll supplement this post.

Sam

Congratulations on the successful certification. Keep in mind with the "call me" trackers if you are not flying at your well established launchsite
with good cell coverage, you could get a very sinking feeling if a completely out of sight flight stays "outa sight" with no return call on the device.
A live tracker gives one real time position information every 1 to 5 seconds as long as there is a satellite lock. Very helpful if one wants to be facing the right direction to be able to see the expected main deployment. Plus it helps to be able to read a map.

It does sound convenient to be able to toss the GPRS tracker in the rocket and go as opposed to having to plan a bay as may be needed with
a live GPS tracker. The live tracker gives a better sense of direction if the upper air winds carry a rocket in an unexpected direction.
Again, it helps to be able to know where to look for a main chute event for a possible visual on the rocket. No matter what one uses to track, a visual is always helpful if it can be had.

One suggestion is don't use the cell phone tracker in a metallic painted or carbon fiber rocket without a cell tower test. Find out where the likely cellphone tower is in respect to a planned launch. Test the device out in the open and then button it up in the rocket in question and see if the airframe shields the device so the signal can't get out to the tower. This is of course more important if the device is going to ride entirely in the rocket as opposed to being attached to the apogee shockcord. If you have any doubts, do the test before you fly and you shouldn't have any surprises. Kurt

Thank you Kurt for the congrats!

I ground tested this unit over 20 times in various configurations (nosecones, items to block signal, hiding behind buildings, under rocks and boards, and logs, even placing it under a metal bowl to see if it would "connect"). Of course, under the metal bowl didn't work, but I did put it under two flights of metal and concrete steps and landings and it worked multiple times. For the areas in which I fly and the altitudes to which I fly (7000' the highest to date with 10,000 likely being my max), this is an ideal setup.

Sure, if I'm in the middle of a desert and going to 35,000AGL, this isn't going to be the ticket. My rockets all have plastic or fiberglass nose cones, Kraft paper or Bluetube tubes, paper and wood AV bays, wood or fiberglass centering rings, and minimal amounts of hardware. I use aluminum av bay sled rods, all-thread, and nuts and washers, but welded stainless shock cord mounts. Again, this works VERY well for me.

It worked so well this weekend, that two of the very experienced L3 fliers that I was launching with (these guys fly K, L, & M motors regularly) LOVE the unit, love the way it worked, and are going to be buying a couple of them for themselves. Currently, they use two-way handheld HAM radios, traditional radio transmitters, and live tracking back to their location on the ground. One even reads off upper air wind speed as his rocket descends. If they like it as much as I like it, I'm where I want to be with tracking at this time.

Thank you for your input too! I like to gather as much information and opinions as I can in this hobby; we can never learn too much!

S


UPDATE on the pre-paid account usage: it's only $.20 per cycle, not $.30. I checked the detailed billing on this account this morning, and I was thinking a "call" would cost $.10. Well, that's only for outbound calls from the number. Incoming calls to the Tracker cost nothing, so each text back to me with position at $.20 per SMS message is the only charge against my GoFone pre-paid balance. After the weekend that started with just over $17 credit on my account, I have $9.80 in the account. There were numerous show-and-tell sessions with various folks all weekend and the 4 flights, so I'm good with that too.

The longer one uses a tracker and the larger the project, I find more people put two tracking devices inside for backup. I haven't had the room yet to be able to do that. I keep say'in I'm going to give up on trying to stuff alot of items inside a small airframe
but keep going back to it as the "stuff" gets smaller as time goes on! Kurt

Yes , very important, you need cell coverage to use it, and since we not so bright , let's not forget to point the rocket nose up on the rail.

UPDATE: Flew the GPS Tracker again this weekend, but only flew to about 3000' due to wind. The rocket (with dual deployment) still landed about 200 yards from the launch pad, so with the onboard tracker, I gave it a test by calling the unit. I received no reply back via text, which confused me as the unit was clearly on when installed in the nosecone.

After retrieving the rocket and getting the nosecone open to inspect the GPS unit, it was fine and appeared to be on (light was green), but it would not transmit data. So I opened up the battery compartment of the Tracker where the SIM card and micro SD cards are also located because it seems to "reset" when the battery is removed and reinstalled. I noticed, however, that the SIM card had been slightly moved likely due to the nosecone hitting the ground. The SIM was not processing the call, nor allowing the unit to transmit back to me.

With this new revelation, I'm going to either heavily tape the SIM card in its proper location or put a dab of epoxy at each corner of the card to make sure it does not become dislodged again. I don't see this as a major concern with the unit, but another slight modification that needs to be made to adapt the unit to rocket flight.

Good day all!

I think SIM card is another weak point... it is held in place by spring contact and will probably disconnect in high G situations. You may try performing drop tests to see if it works with higher G load.

I hear you, and I'm working through the issues as they come up. I don't expect to fly anything much larger than a mid-size K motor, so this is working so far. Oddly, the failure yesterday was with a 2.25" rocket with an H motor. The Tracker's other flights minus one were higher power motors, even a J and a K motor. Go figure, right.............. ?

I think that's the other problem with consumer stuff, they were never designed for high G applications...

Update since there is a new thread started on this GPS Tracker stuff:

I added a piece of cardstock to the SIM card tray on TOP of the card itself on either side of the metal guide that holds the SIM card into the tray. Note that the SIM card tray is recessed into the lower battery compartment, but it's not a super tight fit as far as tolerances go. This modification is meant to fill the gap between the top of the installed SIM card and the bottom side of the battery that covers it in an installed configuration. The card stock is held in place with a small spot of CA on the card itself to prevent it from moving during flight/landing. With a very minimal gap between the top of the SIM card and bottom of the battery, the card shouldn't move much, if at all. I also put a small piece of cardstock (not glued) on the edge of the SIM card that slips past the retaining clip. I didn't glue this one as I will likely need to remove the card at some time and didn't want to have to fight the little metal "keeper" for the SIM card.

Also, I took a little thicker stock just under the width of the battery and wrapped it around the battery starting just behind the contacts and wrapping longways round the battery until the card reached almost back up to the battery contacts on the other side. This created a big U-shaped wrap around the battery. What I'm trying to accomplish is keeping everything tight and in its place during flight. It did not appear the battery was moving off the contacts, but some movement was possible when I poked around with my finger trying to move the battery side to side and such. I could shake the GPS unit, and I didn't hear that battery moving or rattling, but my measurements told me there was a gap above and/or below the flat side of the battery that could be filled.

This just snugs everything up, and more flights will happen this weekend, many with the Tracker...

Thanks for the updates I just bought 2 - but am far from AT&T store to get cards and activate, but digesting all your suggestions and hope to be up and running soon with them