Inexpensive GPS Tracking

cerving said:

Have you had a chance to fly it yet?

At 5 updates every 30 seconds at 10 cents per text, that equates to 60 cents per minute of operation. That could get expensive if your rocket sits on the pad for awhile waiting for your launch slot, especially if you have a misfire and you have to do it all over again.

Click to expand...

To locate a lost rocket, you would only need to ping it once after the rocket lands. So, the cost would be just 20 cents per use.

-- Roger

That makes sense, although it would be nice to have an "I'm alive" message once in awhile. One message per minute would probably work, starting shortly before launch. Sounds like it's worth a try.

I found out something you should avoid doing with the cheap GSM GPS Tracker ... don't accidentally press the "SOS" switch on its side. When pressed it begins sending periodic texts with the device's location to all of the numbers you have registered in the device. It sent about 10 texts to each of our smartphones before I realized what was happening.

-- Roger

FYI, both AT&T and T-Mobile have $2 per day prepaid unlimited text plans, you're only charged for days that you actually use the device. You can buy a $10 prepaid card, and it's good for 90 days, so if you only fly once or twice a month this could be very economical. Even if you press the SOS button and it starts spamming you with texts...

I couldn't resist, I bought one of these for $27.98 on eBay. There's a lot of guys selling them...

Tetrahedron said:

I kinda like the MT-400 using APRS. With a GPS-antenna and VHF-antenna it's about $220. I wonder what the best battery is for this?
I would probably use a 9V Ni-Cd or Ni-MH 1000mAh, would these work without damaging the unit? What about some Lipo batteries?

https://www.byonics.com/mt-400

-John

Click to expand...

Ok,

If you use the MT400 You will need to mount it in your nosecone away from your deployment electronics. High Rf fields will dork your deployment altimeter.
I have seen charges deploy on the pad when the altimeter was turned on and I've seen two deployment altimeters lock up in a 16 foot tall 10" diameter project that then came in ballistic. Garmin dog trackers on the MURS band can have the same effect.
The 12mW Beeline trackers both NDB and APRS/GPS can ride next to the deployment electronics without a problem. Once one gets above 50mW output, I suggest you setup your rocket at home with bare ematches on the altimeter, turn on the Rf beacon and then the altimeter. Let the whole thing sit for awhile and see what happens. If the ematches fire, you have a problem. If the altimeter shuts down and the ready beep halts, you have a problem.

If using an MT400 as a beacon, you're right, you'd need a high capacity pack like 1000mah. Sooooooo, the MT400 setup one would likely want to save for a large project where you can mount it away from your altimeter(s). You could line the ebay with shielding, something like this:

https://www.goldmine-elec-products.com/prodinfo.asp?number=G17455

Or look up a Faraday cage to protect your altimeters. Kurt

ksaves2 said:

Ok,

If you use the MT400 You will need to mount it in your nosecone away from your deployment electronics. High Rf fields will dork your deployment altimeter.
I have seen charges deploy on the pad when the altimeter was turned on and I've seen two deployment altimeters lock up in a 16 foot tall 10" diameter project that then came in ballistic. Garmin dog trackers on the MURS band can have the same effect.
The 12mW Beeline trackers both NDB and APRS/GPS can ride next to the deployment electronics without a problem. Once one gets above 50mW output, I suggest you setup your rocket at home with bare ematches on the altimeter, turn on the Rf beacon and then the altimeter. Let the whole thing sit for awhile and see what happens. If the ematches fire, you have a problem. If the altimeter shuts down and the ready beep halts, you have a problem.

If using an MT400 as a beacon, you're right, you'd need a high capacity pack like 1000mah. Sooooooo, the MT400 setup one would likely want to save for a large project where you can mount it away from your altimeter(s). You could line the ebay with shielding, something like this:

https://www.goldmine-elec-products.com/prodinfo.asp?number=G17455

Or look up a Faraday cage to protect your altimeters. Kurt

Click to expand...

I agree, I have the Beeline 1W 2M APRS GPS transmitter and it was mounted in the nose cone when I flew it.
I have flown the Beeline 70cm APRS GPS transmitter in the altimeter compartment and it worked without any
mishaps as well as other transmitters and the ARTS Ozark GPS but these are all around 10-20mW or so.

-John

I used the tracker on my helicopter at the last NEFAR launch. Unfortunately, it didn't work because there's no AT&T coverage at the launch site. I tried calling the device and, when that didn't work, I sent it a text command. Funny thing is, when I got home I got a reply from the tracker telling me that its location was ... my home. I guess it didn't receive the text message until we got home and I took it out of the trailer into the house.

-- Roger

cerving said:

FYI, both AT&T and T-Mobile have $2 per day prepaid unlimited text plans, you're only charged for days that you actually use the device. You can buy a $10 prepaid card, and it's good for 90 days, so if you only fly once or twice a month this could be very economical. Even if you press the SOS button and it starts spamming you with texts...

I couldn't resist, I bought one of these for $27.98 on eBay. There's a lot of guys selling them...

Click to expand...

I've seen this very important note or something similar in the eBay ads for many of these units at that price point and below, but not in other visually identical ones at the same price points:

"Note: 1.This product does not rely on GPS positioning, rely on the GSM/GPRS baseband station location."

Some of them just say something like "Does not include GPS chip." Highly deceptive sellers saying that the unit is a "GPS Tracker" in the title and then including a note (or not including a note) that it doesn't actually use GPS!

So buyers beware and if and when you get one of these and find one that actually does use GPS and works well for one or more flights, please provide a link to exactly which one you bought on eBay.

Winston said:

So buyers beware and if and when you get one of these and find one that actually does use GPS and works well for one or more flights, please provide a link to exactly which one you bought on eBay.

Click to expand...

I did a search for that phrase and I see that it's turning up a different type of product. And, you're correct to warn against using such products. Not only will they not work as well in a remote area, but they require a subscription to a web-based service that calculates the location from the cell tower IDs.

The devices that we are talking about, such as the one I bought, use GPS.

-- Roger

jadebox said:

I did a search for that phrase and I see that it's turning up a different type of product. And, you're correct to warn against using such products. Not only will they not work as well in a remote area, but they require a subscription to a web-based service that calculates the location from the cell tower IDs.

The devices that we are talking about, such as the one I bought, use GPS.

-- Roger

Click to expand...

That's the one I've been considering. Here's an eBay ad for one for $29.99 (with 710 sold):

https://www.ebay.com/itm/Spy-Vehicl...77?pt=US_Tracking_Devices&hash=item416f0d3519

HOWEVER, even if one knows what a particular unit which actually uses GPS looks like, Chinese sellers are so bereft of ethics that they'll gladly sell a piece of junk that "looks right." For instance, here's a unit that looks exactly like the one above selling for $249.99 (with 81 sold)!

https://www.ebay.com/itm/RealTime-G...00?pt=US_Tracking_Devices&hash=item233351d03c

Are there really that many idiots who pay $249.99 for a device being sold for $29.99 elsewhere on eBay or am I missing something?

This is why once someone successfully tests one of these in a rocket, they need to state exactly which one they bought and where they bought it.

BTW, I looked up the lousy accuracy when using just GSM tower triangulation and found this comment. Note that none of the cheap GSM-only trackers on eBay I've found use 3G data connections:

"With a 3G connection and recent (>2008) Nokia mobile phone without GPS chip you can get to 100m accuracy. Without 3G connection, accuracy is around 1000m. However, all this depends how many cell towers there are around."

You're not missing anything except for a $220 price difference for the exact same TK102 unit.

Buyer beware.

https://www.ebay.com/itm/Mini-A8-GS...d=100005&prg=8934&rk=3&rkt=5&sd=151184855100& is even a smaller GPS tracker for only $18.14!

Bob

bobkrech said:

You're not missing anything except for a $220 price difference for the exact same TK102 unit. Buyer beware.

Click to expand...

So, I guess there are people that stupid... wow.

https://www.ebay.com/itm/Mini-A8-GS...d=100005&prg=8934&rk=3&rkt=5&sd=151184855100& is even a smaller GPS tracker for only $18.14!

Click to expand...

Unfortunately, from its stated specs and the lack of any specific mention of a GPS chip, that looks like one of the ones that claims to use GPS in its title, but actually just uses GSM triangulation.

jadebox said:

I used the tracker on my helicopter at the last NEFAR launch. Unfortunately, it didn't work because there's no AT&T coverage at the launch site.

Click to expand...

That's odd. I get great, (well maybe just good) coverage at the Clegg's... I'll have to check again this weekend (you going?)

brianc said:

That's odd. I get great, (well maybe just good) coverage at the Clegg's... I'll have to check again this weekend (you going?)

Click to expand...

AT&T's coverage is different for their pre-paid plans. I just looked at AT&T's coverage map. It shows "partner" coverage right at the launch site where I was unable to use it. But, it shows "moderate" all around the sod farm. So, it might have worked on a rocket that drifted out of the farm. But, that doesn't inspire much confidence.

I'm planning to attend on Saturday. Right now the weather forecast isn't promising, but there's time for it to change.

-- Roger

jadebox said:

Under the "10 cents a minute plan" that I chose, you pay 10 cents a minute for calls and 20 cents each for text messages. You prepay using a credit card and can set it to refill the account automatically. It's a voice and text plan only, no data. You aren't charged for texts or minutes until you use them. so there's nothing to expire.

-- Roger

Click to expand...

I got this tracker now but when I went to my local ATT store they say: $25 to get the SIM and activate and
then you add account money, say $15 and it's 20cents/text message. The only problem is that it expires
after 30 days or 3 months if you add more into account. After that, any remaining money you diddn't use you loose:sad:,
which is not what I want. I need something like add $30 into account and it never expires or at least good for a year.

-John

Tetrahedron said:

I got this tracker now but when I went to my local ATT store they say: $25 to get the SIM and activate and
then you add account money, say $15 and it's 20cents/text message. The only problem is that it expires
after 30 days or 3 months if you add more into account. After that, any remaining money you diddn't use you loose:sad:,
which is not what I want. I need something like add $30 into account and it never expires or at least good for a year.

Click to expand...

Yeah ... I think that they've either changed something or it wasn't made clear when I activated the SIM with AT&T. The balance, though, doesn't it expire if you refill it. But, that doesn't make sense unless you plan to use the service often.

-- Roger

You could look at tmobile's pre paid plans. I know their minutes are good for a year after you have pre paid $100. Not ideal, but at least it is good for a year.

They also have $10 pre paid plans that are good for 90 days and $2 per day plan.

https://prepaid-phones.t-mobile.com/prepaid-plans

2.00 per day might be good if you only fly a couple times per month or don't fly monthly. That way nothing would expire.

You'll need to verify that the $2/day doesn't expire. They don't say on that web page.

I'm not sure what the better choice would be. $2/day gets you unlimited texts, but how many would you really need? I'd guess you only a couple per flight.

Just spoke to TMobile and here is the info. You buy their Sim card 9.99+tax. Minimum load to account $10.00, 2.00 per day unlimited text,talk web @2g speeds. Balance good for 90 days. if you only fly 1 day per month you would forfeit ( money expires) $4.00 at the end of the 90 days. Even with that you are only talking about $3.33 per month at the worst case scenario, if you fly more often then you just recharge $10.00 at a time and the expiration clocks resets every time you recharge account. That seems like a minimal expense on the scale we spend money flying.

Any TMobile store can get you the correct size Sim Card (so take the device) and set up the Pay As You Go account. They are not the same division as the Monthly plans and can not be combined.

Hope this helps anyone thinking of using TMobile for this.

T-Mobile has decent coverage at Lucerne Valley, but they're notorious for poor coverage in rural areas. Do your homework first... AT&T may be the only game in town in many places.

accpool said:

Just spoke to TMobile and here is the info. You buy their Sim card 9.99+tax. Minimum load to account $10.00, 2.00 per day unlimited text,talk web @2g speeds. Balance good for 90 days. if you only fly 1 day per month you would forfeit ( money expires) $4.00 at the end of the 90 days. Even with that you are only talking about $3.33 per month at the worst case scenario, if you fly more often then you just recharge $10.00 at a time and the expiration clocks resets every time you recharge account. That seems like a minimal expense on the scale we spend money flying.

Any TMobile store can get you the correct size Sim Card (so take the device) and set up the Pay As You Go account. They are not the same division as the Monthly plans and can not be combined.

Hope this helps anyone thinking of using TMobile for this.

Click to expand...

As cerving already stated, do your homework first. Make absolutely sure the daggum thing is going to work in your field. I used to have T-Mobile pay as you go plan for a smart phone and I am of the thinking that I will NEVER EVER use it again. Ever. The service can be very spotty or non-existant.

On the other hand the cheapie smart phone I got makes for a handy dandy Pandora player at home with the WiFi.

-Dave

accpool said:

Just spoke to TMobile and here is the info. You buy their Sim card 9.99+tax. Minimum load to account $10.00, 2.00 per day unlimited text,talk web @2g speeds. Balance good for 90 days. if you only fly 1 day per month you would forfeit ( money expires) $4.00 at the end of the 90 days. Even with that you are only talking about $3.33 per month at the worst case scenario, if you fly more often then you just recharge $10.00 at a time and the expiration clocks resets every time you recharge account. That seems like a minimal expense on the scale we spend money flying.

Any TMobile store can get you the correct size Sim Card (so take the device) and set up the Pay As You Go account. They are not the same division as the Monthly plans and can not be combined.

Hope this helps anyone thinking of using TMobile for this.

Click to expand...

Thanks for the info. I think that's what I will do, either the $2/day or 20c/message deal and just renew $10 each time.
I'll give a report after I used it in my rocket. The GPS programming is pretty advanced, you can even tell it to text you
if it moves >X ft from it's current location after it landed... I'll see how well it can get GPS and send from inside the rocket on the ground.

-John

Tetrahedron said:

Thanks for the info. I think that's what I will do, either the $2/day or 20c/message deal and just renew $10 each time.
I'll give a report after I used it in my rocket. The GPS programming is pretty advanced, you can even tell it to text you
if it moves >X ft from it's current location after it landed... I'll see how well it can get GPS and send from inside the rocket on the ground.

-John

Click to expand...

Well, I had a chance to test it in my rocket and it worked pretty good. It's not giving a perfect GPS coordinate but at about
within 50 ft or so. The rocket went to 3700 ft and only landed some 1500ft away and I after 2-3 text messages it sent me
a text message back with the location. I placed it in my altimeter bay together with a regular transmitter as a backup.
I also tried it a second time in my buddy's rocket this time in his nose cone to about 4500ft and while it was descending
on a chute it sent me text message with GPS coordinate still in the air and then later on the ground this time about a
half a mile away. Not to bad for a $50 GPS tracker. I used the ATT 10c/minute plan with the $5/200 messages option
good for 30 days. I will continue to test it in some more rocket flights.

-John

Ummmmmm,

For $90.00, one can buy one of Cerving's GPS tracking kits, transmitter and receiver. One won't need no "stink'in" cell phone service. Yeah it's not $50.00 but something to think about.

https://www.eggtimerrocketry.com/page21.php

Add an HC-06 B/T transmitter($5.00 to $6.00) to the EF receiver and stick this program into one's android device:

https://play.google.com/store/apps/details?id=com.frankdev.rocketlocator

Uses the Android's GPS and reads the incoming NMEA data on the incoming "rocket" data. Walk right to the rocket and no manual
inputting of data on an external handheld mapping GPS. Automatic data input used to cost mucho dinero as outlined below.

I am excited that GPS rocket tracking is drastically dropping in price for a self contained system that will get the job done.
One doesn't have to buy a $450.00 radio, $300.00 handheld mapping GPS and a $289.00 APRS tracking radio anymore. (Plus a Ham license ~$17.00)

I'm not giving up my BeelineGPS trackers because of the onboard recording memory. More datapoints can be had for download after recovery.
Miss a few packets via Rf and no problem to pickup the rest of the track on download.

Also, losing a $70.00 tracker as opposed to a $289.00 tracker is a little easier to swallow. (How does one "lose" a tracker. Easy, have a recovery system
malfunction. I've seen altimeters survive core sampling but never a GPS tracker.)

Kurt KC9LDH

Tetrahedron said:

Well, I had a chance to test it in my rocket and it worked pretty good. It's not giving a perfect GPS coordinate but at about
within 50 ft or so. The rocket went to 3700 ft and only landed some 1500ft away and I after 2-3 text messages it sent me
a text message back with the location. I placed it in my altimeter bay together with a regular transmitter as a backup.
I also tried it a second time in my buddy's rocket this time in his nose cone to about 4500ft and while it was descending
on a chute it sent me text message with GPS coordinate still in the air and then later on the ground this time about a
half a mile away. Not to bad for a $50 GPS tracker. I used the ATT 10c/minute plan with the $5/200 messages option
good for 30 days. I will continue to test it in some more rocket flights.

-John

Click to expand...

I flew it again at RGXVI last weekend and it worked fine, although the rocket only landed 1/4 mile away.
The real test came when my buddy flew it in his rocket to 12000ft at Mach1+. We also had a beeline 70cm GPS
which I also tracked on my Kenwood radio with built in APRS. The rocket landed some 1.5 miles away.
Again the GPS tracker was within 200ft of the rocket, this time in a tree. The beeline GPS marked about the same spot.
Then on Sunday I flew it again on my rocket and it landed some 0.8 miles away up in a tree again, GPS was right on the spot.
The ATT coverage at this field is also ok but it takes a couple of tries to get coverage on my cell phone at the field.
It's expensive and will cost you $10/launch unless you can borrow someone SIM card and depending on how much
you pay for text messaging with your provider. I will continue to test it for some more flights.

-John

cerving said:

That makes sense, although it would be nice to have an "I'm alive" message once in awhile. One message per minute would probably work, starting shortly before launch. Sounds like it's worth a try.

Click to expand...

I am using the tk102 and got it on amazon for about 27 bucks. It DOES have GPS. I went through t mobile and for twenty bucks a month you can program the device to send the device location as text message with a location lat/long you can open in Google maps. I have it seems the signal every 3 minutes. Unlimited text. Why not. Come with a little waterproof bag. Of year tells how much battery is gos unit has left. The amazon one came with two batteries. I started flying at 3p one day and when I checked my texts at 10a the next day ( I had forgotten to turn it off it was still sending coordinates. 5 percent battery life let at that point. Not bad for under 30 bucks. Has gsrm capability too, but I haven't figured that out. I not a real technical but and the instructions are translated into English and a little weird but I figured it out without any problems really. Less than twenty minutes. 10 bucks for Sim card. 10 dollar deposit. 20 bucks a month. If you don't fly much try a different plan. You CAN call the cSIM ✆ number it will hang up on you and it immediately texts back gps. I got the SIM with no voice. Just unlimited data text. When I start flying less I might switch to different plan. But twenty bucks a month is with it. My first phantom had a flyaway after 5 days. But I can DEFINITELY say the tk102 on amazon HAS gsm...GPS...GPRS....

After crashing an expensive TAGG I tried the TK102 GPS tracker ( around $20 on EBAY ) and it is the best !! Perfect performance the last two launch days. I bought a $3/month T-mobile sim card which gives you 30 fixes per month. Now I am working on an Arduino altimeter with $7 in parts to minimize the cost of crashes.

Wayne in South Florida