$25 GPS Solution

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How many others do you know use 70cm at a launch? Is it usually that crowded where you fly? As far as I know, the range of frequency programming options spans the width of the band.

Almost everyone flying HPR at my club in the summer is using 70cm BRB trackers. On some weekends there could be 15-30 users of 70cm. Regulars have frequencies already assigned. Plus the club makes available about a dozen trackers for guests and others to borrow. We have a local rule is that it is forbidden to leave rockets in adjacent farms field. Rockets and shock cords do not go well with harvesting equipment.
 
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I believe it's "do not go well" with harvesting equipment. :wink::facepalm::rolleyes: Kurt
(no harm intended as I mess up words a lot too!)
Oh, If your launchsite is that busy, to be honest with you, I wished I lived where you live.
It's like trying to be a scuba diver in Central Illinois which is actually a wrong place to
live for that!!
 
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Vance, to what device are you sending the data (over bluetooth) and what program/s are you using?
I was mainly using that for testing the devices for other uses.
I was hoping to be able to connect to ios and android devices but as is it only works with android.
I tried to get the rocketlocator app working but never had much luck. Bluetooth gps https://play.google.com/store/apps/details?id=googoo.android.btgps&hl=en works well however to find the coordinates.

The only difference between the ground and air modules is the ftdi chip and power regulators, if you are good with a soldering iron you can connect direct to the TX and RX from the radio module on the board. I just found it easier to use an air module.
 
GPS Rocket Locator in a nutshell: Download and install it. Don't open it yet. Fire up your tracker and receiver. Let the tracker sit outside and wait awhile till it gets a lock. EggFinders are easy in that regard because the yellow LED starts to flash 1/sec with
incoming positions. Pair your B/T receiver with your Android device. Now, open GPSRL. First thing it will get is get stuck on the Google Maps screen. Google gets ticked with people using their tiles "for free" and sabotaged this so it no longer works.
Soooooooo, Click on the upper right menu pulldown and select "Map Provider". Hit "Open Street Map" and as long as your device's GPS has a lock your position will be posted. You may have to zoom out to see some streets but you get this far, you're in
decent shape. Next, go to the upper right pulldown menu and hit "Settings". Change your units if you like and click "Bluetooth Device". If you paired your B/T receiver you should see something like HC-06 (which is in my EggFinder LCD) click on this and wait.
You should begin to see the red pushpin that is your tracker with a line drawn to it eventually. Remember "North" is "UP" on your screen and you make your "blue dot" and red pushpin come together to find it.

Some caveats: With the photomap tiles that are no longer available there is a "Rocket Distance" "Current Altitude" and "Max Altitude" listing in the upper left side of the display. Since most of the open source maps have a white background, the letters won't show up. The Rocket Distance is apparent and not so likely that accurate unless you stand next to the tracker and you could see the distance from decrease. The Current and Max Altitudes somehow both names get fixed to "Current" I believe when positions
are plotted. Sirf4 chipset is lousy with altitude anyways so not that terribly important.

"Download Map" does what it says. You have the room/memory space, you can at least download the OSM maps at a variety of zoomlevels to store "on device" so you don't need internet connection to track at your launchsite.

The program doesn't "navigate" but it does automatically show a datum line from your position to your rocket (or last known position). If you "lose" your local position on the screen, hit "Follow Me" in the lower left and your position will be centered on the map
shortly and you can re-observe the datum line to your rocket/tracker.

I haven't tried it yet but if you get a screen record app, that might be one way to "save a flight" for what it's worth and play it back. I find that at least with the 100mW trackers you don't recover/decode all the positions. You'll get enough
to recover your sport rockets though. If you can, blow the main up higher because with the slower descent and better propagation at altitude you'll get more positions painted and can get an idea of a drift trendline.

When the app first came out there were no off line maps available. The tracker still worked and I used it that way for a flight and I didn't lose the rocket. When map caching came on, I downloaded a pile of Google map tiles for
my local sites before it no longer functioned. I pulled the tiles to a USB stick and plop them into new installs of GPSRL and they work. There is an open source GIS photomap server that is used with APRSISMO and APRSISCE/32
that is a few years old but very nice. Unfortunately GPSRL is not open source and I believe it would be easy to substitute the address for these accessible maptiles but I don't believe the author is open to suggestions. He posted one time
he no longer has time to work with the program.

Another thing: GPSRL won't work with an Android device that doesn't have an onboard GPS chipset. The Android site won't let you download it so that is out. I have two dual boot Android/Windows tablets I mail-ordered from China
2 years ago that have an onboard GPS chipset that will work in Android and with some hacking, in Windows. If you can find a source for a newer "dual boot" with an onboard GPS chip, oh and mind you has a data radio tuned to one of the North American cell phone systems post the link and email me! Kurt
 
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This GPS might be a possibilty to use with this hardware: https://www.sparkfun.com/products/13740 I have a couple and will look into it. AKS
I looked at that unit and as long as you use a good power regulator it should be fine.
According to the data sheet the maximum input voltage is 3.6v.
A lot of the other raw chips or modules can handle 3-5v which means they can run direct from a 1s lipo.
 
I looked at that unit and as long as you use a good power regulator it should be fine.
According to the data sheet the maximum input voltage is 3.6v.
A lot of the other raw chips or modules can handle 3-5v which means they can run direct from a 1s lipo.

Yeah I saw that. I have some small voltage regulator boards here. I used one to restore a busted 1st generation EggFinder. The one with 3.3V terminals on the
board. Took the signal wire and soldered it to the appropriate bad and the salvage job was done. Did a Ublox chipset too. With Ublox the decoding at the LCD is spotty of the altitude but the lat/long is dead on so still usable for tracking. I did get a couple of the GPS units the OP recommended.
I want that 500Mw output on 433Mhz. I've gotta go looking for the setup program for it. I have a hacked APRSIS/32 setup on some Windows
tablets that will show a breadcrumb trail with the recorded altitude beside each dot. I suspect with the 100mW, 915Mhz the power output is too
low to get totally reliable, 100% decoding of positions on the ground. When I drive around with the set in a vehicle, I get 100% decoding and
plotting on the photomap screen. I'm suspecting using a higher power output on a band that has better propagation, 433Mhz, I'll see better
recovery and plotting of positions. That and I have a 7 element Arrow antenna handheld Yagi that certainly will improve the reception of
the signal. On the 70cm/433Mhz band, the beamwidth of the Yagi makes it possible to track in flight reliably. Kurt
 
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How exciting! GPS antenna should arrive soon! The casings for the radios separate easily. Now go download mission planner and get the radios talking to each other! Just remember to ensure you have an antenna installed on the transmitter before powering it up or you risk smoking the board (ask me how I know).
 
Just purchased a batch of this stuff to experiment with, including the 500mW version (I have the advanced radio ticket, VK3TRK :)).

I think this might go into the NC of the Nike Apache when I get around to the two-stage flight.
 
Just purchased a batch of this stuff to experiment with, including the 500mW version (I have the advanced radio ticket, VK3TRK :)).

I think this might go into the NC of the Nike Apache when I get around to the two-stage flight.

Nice call sign! Vanity?

I will have time Monday to tinker with the receiver. As was mentioned by ttabbal, I was able to identify two of the four gold pads as voltage pads, the one on the right being ground. If the other two are data then we are go for a bluetooth connection.
 
It would be the cat's meow if we could inject ones callsign into some of the data strings without messing up the decoding but I guess coming on air with an H/T would suffice for now. Kurt
 
My 3DR radios came in yesterday. I dissected one of the little 6 connector wires, and wired in a 1S 500mAH LiPo cell to the V and G terminals of the air module. I used a little Molex 2.0 type connector which the LiPo has on the end. Wanted to keep it so I could still plug it into my little Syma quadcopter.

Downloaded Mission Planner, and stumbled through it. This is all quite new to me, so I am wandering through the fog. However, a future project involves building a custom quad-copter so I needed to learn this stuff anyway. I also took delivery of a nifty little Arduino Uno experimenters kit yesterday, so that sits ready for my tinkering pursuits at some future point.

I first tried to load Mission Planner on a laptop that still runs XP, but had no luck there. I use that laptop for running field programs, like my OBD2 automotive diagnostic programs. I installed net framework 4.0 on it, per the Mission Planner install instructions, rebooted....and it still says I do not have net framework 4.0. Oh well. I was hoping to use that laptop to receive the GPS data at the launch site. Next I'll attempt putting that on my Windows 10 laptop, that I would rather have stay away from field operations.

Anyway, GPS still has not arrived, but I wanted to make sure the radios were operational first. I ended up installing Mission Planner on a Windows 7 desktop, and got it to run after another net framework update. I got this screen from Mission Planner after loading the settings, so I am guessing this means all is copacetic.
MPScreen01crop.jpg
 
Program the radios with the win10 machine at home and use your beater laptop in the field with your GPS program of choice. I like these:

https://www.visualgps.net/

https://www.u-blox.com/en/product/u-center-windows

Looks like you have it figured out. Do your radio LED's remain solid shortly after power-up? What color are the LED's?

Tomorrow is the day I should receive proper OTG cables and will also have some time to play with the bluetooth side as well. Stay tuned for updates on wired and wireless mobile solutions.
 
Both ground and air LED's are solid green. If I unplug the ground unit, the LED on the air device starts blinking green. That is all I can say for now.
I hope I can run the GPS program on the XP laptop. It is an old Averatec that has seen a great many air miles, while I was still in the employ of industry. It proved to be quite rugged. If I get it all working on the ground, I'll post some updates.

Just checked AliExpress tracking, and GPS should be here tomorrow. We will see. I was playing around with a great circle route plotter program, and noted that a direct air route from Shenzhen to New York, JFK airports (per the tracking updates) takes a plane almost directly over the north pole. I got to wondering if the Russians will let them do that.
 
Sounds like your radios are ready. I still have a 12 year old Samsung Q310 that I use for tinkering/field stuff. I've reformatted twice and replaced the disk once (wanted more space). Pretty sure my cpu fan died a year or so ago and although it gets warm the damn thing still runs. Ran win7 only and never used antivirus. Things last for as long as you take care of them.
 
Got my 433 radios today. Unfortunately it came with 2 SMA male antennas but the AIR module is also an SMA male. For those who have these does yours have different SMA genders on your modules?
 
Got my 433 radios today. Unfortunately it came with 2 SMA male antennas but the AIR module is also an SMA male. For those who have these does yours have different SMA genders on your modules?

Mine came the same way as yours did on the 100mw . the 500mw was correct I could hook up the antenna .

I contacted the seller they are sending me a new antenna .
 
Both my air and ground modules (100mW) were SMA female, and both the antennas were SMA male.

Got my GPS module delivered a couple hours ago, and now trying to figure out the color coding on the transmit and receive wires without taking it apart just yet. I have a red and black (assuming V and G respectively), but then have an orange and light blue set of wires. They are terminated in what appears to be standard Dupont female ends. I have some header pins at my workbench for Arduino projects. Wanted to rig this up on a breadboard first for testing.

Edit to add: Found a diagram and some info on "BangGood" website selling similar item. It looks like orange is connected to GPS transmit TX, and therefore connects to radio receive RX. Blue is GPS receive and connects to radio transmit.

https://www.banggood.com/NZ-GPS-For...-ZMR250-Multicopter-Quadcopter-p-1015134.html

2nd Edit to add: Apparently the blue and orange were reversed on my GPS. Triple checked everything when I was not getting communication in U-center. Finally, and without opening up the GPS shell, I reversed the leads on TX and RX from what I inferred was correct, and got communication.
 
OK, and please bear with me here. This is screen shot from U-Center. I have communication over the radio on COM7. The status is flashing green on the bottom COM7 at 57600 baud after I figured out the reversed TX-RX deal. However, the packet console indicates errors, and no GPS data is being deciphered. Is this related to the airspeed setting on the radio?
UCScreen01.jpg
 
OK, and please bear with me here. This is screen shot from U-Center. I have communication over the radio on COM7. The status is flashing green on the bottom COM7 at 57600 baud after I figured out the reversed TX-RX deal. However, the packet console indicates errors, and no GPS data is being deciphered. Is this related to the airspeed setting on the radio?
View attachment 325212
Change the com port speed until you see some strings decoded properly. I don't know what the default mode is for the GPS chipset you're using. Try 9600. I haven't received mine yet so I'm not speaking from of position of authority.
My experience in the past is usually a comport mismatch or serial protocol issue. Kurt
 
Change the com port speed until you see some strings decoded properly. I don't know what the default mode is for the GPS chipset you're using. Try 9600. I haven't received mine yet so I'm not speaking from of position of authority.
My experience in the past is usually a comport mismatch or serial protocol issue. Kurt

OK, I have attempted changing the U-Center speed around a bit. The message keeps repeating on all those baud rates every 46 seconds. I experimented with the com port speed on computer serial port itself, and still no cigar. I have not changed the radio communication speed baud rate though.

The GPS came with zero documentation, and for the price I figure I got what I paid for in this case. There is a combination of elements here that will eventually result in success, and I just have to find it. The GPS has a solid red LED when power is on, and then after a few seconds I get a blinking blue LED, flashing about once a second. From what I can tell, this means it is getting signals. There is also a yellow LED on the air module radio that now flashes in pulses once per second as well, which I figure is packets being sent. So, the hardware seems to be working and I just need to find the right combination of software interfaces...or so it seems.
 
Now we are cooking with a bit of gas. I had to set everything at 9600 baud. Computer port, radio communication speed, and U-center. It took a few hits to get the radio to set at 9600, but when everything was coordinated at that baud speed, the screens lit up instantly. Here is screen shot from U-center showing satellites, and my location quite accurately. The GPS is indoors on my workbench behind me, under a roof. Distance between the units is about 8 feet. The radios are set at 11, which is 12.5 mW.

So, we do have an operational system here is seems, for less than $25. Next, I'll investigate the last piece of software described by the OP. Then, I will make this portable for field tests, and get my HT tuned to correct frequency for broadcasting my call sign at maybe 1W. Then boost the radios to the full 100mW. It indeed would be great if the system could be configured to broadcast the call sign at the required intervals.

UCScreen02.jpg
 
OK now you're talking. I still think the best bet for field work is a Bluetooth receiver link to one's tablet or laptop. I like something small enough to carry out in a field to go after the rocket. Kurt
 
My 3DR radios came in yesterday. I dissected one of the little 6 connector wires, and wired in a 1S 500mAH LiPo cell to the V and G terminals of the air module. I used a little Molex 2.0 type connector which the LiPo has on the end. Wanted to keep it so I could still plug it into my little Syma quadcopter.

Downloaded Mission Planner, and stumbled through it. This is all quite new to me, so I am wandering through the fog. However, a future project involves building a custom quad-copter so I needed to learn this stuff anyway. I also took delivery of a nifty little Arduino Uno experimenters kit yesterday, so that sits ready for my tinkering pursuits at some future point.

I first tried to load Mission Planner on a laptop that still runs XP, but had no luck there. I use that laptop for running field programs, like my OBD2 automotive diagnostic programs. I installed net framework 4.0 on it, per the Mission Planner install instructions, rebooted....and it still says I do not have net framework 4.0. Oh well. I was hoping to use that laptop to receive the GPS data at the launch site. Next I'll attempt putting that on my Windows 10 laptop, that I would rather have stay away from field operations.

Anyway, GPS still has not arrived, but I wanted to make sure the radios were operational first. I ended up installing Mission Planner on a Windows 7 desktop, and got it to run after another net framework update. I got this screen from Mission Planner after loading the settings, so I am guessing this means all is copacetic.
View attachment 325187

I take it one plugs the flight module into the computer using a micro USB cable? One good for data and plug in the receiver via USB socket? Kurt
 
There was no provision for the flight module for a USB. I deduce that the flight module is programmed via radio link when the ground module is plugged in to the computer running Mission Planner.

I hooked up +V and Ground to the LiPo battery (1s 500mAh) to the air module, and that was all. The green LED on the air module will light up. Then I plugged in the ground module to the computer, and its green LED comes on. If one module is powered, and the other is not, then the green LED will start flashing on the powered one.

I found using device driver which com port had been assigned to the ground module. It was fairly easy to find that. Then, in Mission Planner, I went to the Initial Setup screen, and click on "Optional Hardware". In this list was "Sik Radio". In the upper right hand corner of the screen is the com port and baud rate drop down menus. When I first started, it was com 7, and baud was 57600. The instructions said to NOT hit connect at this point. I hit "Load Settings", and after about 15 seconds the blanks in the form filled in with both the ground and air module settings from the factory.

edit to add: Per the OP, I always made sure antennas were securely attached before any power was applied. OP alluded to this letting out "magic smoke" if they were not on.

The main thing to change is baud rate, both air and ground to 9600.

I went back and changed the baud rate on the com port 7 in device driver to 9600. Then you should be ready for the GPS module when it arrives.
 
I hooked up +V and Ground to the LiPo battery (1s 500mAh) to the air module, and that was all.

So even though the air module says "5V" it can run just as well on less than 5? (1S Lipo).
 
The radio module in these boards can run on 2.4-3.6v the have a LDO regulator onboard to regulate the 5v down to 3.3.
They seem to run fine across the full voltage range that a 1s lipo provides .
If anyone has any data on if differing voltages affect range it could be interesting.
 
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