Small GPS Transmitter

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darrena

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Hi
Iam bulding a wildman blackhawk 38 and have a Adept 22 altimeter already.
I am looking for a GPS unit I can track using a mobile phone and satnav unit, they have a few on ebay over here in the UK for as little as £35 but they are a little too big for the blackhawk. I was wondering if a similar product was available in the US that would transmit coordinates via text to a mobile phone?
 
I do not think so at that budget. A lot of us are using Big Red Bee "Beeline" radio transmitters which are about $70 (£47), but they fit inside a 29mm tube and can be tracked by a tuned yagi antenna. BRB provides the plans to make the yagi. I have built one and it only took about 3 hours. Big Red Bee does make GPS transmitters, but they are a lot more pricey. They are great units.

What you are probably seeing on e-bay are units made in China. Those can be obtained here as well, although they are not considered too reliable.

https://www.bigredbee.com/
 
Not yet....but in development. Could be here by Aug. [MissleWorks] Fully utilizing GPS in phones. Totally independent from cell towers [no needed coverage]
 
I'm waiting to hear something the new Missileworks unit CAN'T do (other than "be available right now").

s6
 
stealth6 said:
I'm waiting to hear something the new Missileworks unit CAN'T do (other than "be available right now").

s6
Click to expand...

What it cannot do is all related to size, and the need for add-ons.

It can't fit in 24mm tube. It can't use accelerometer-triggered events without an addon board. It doesn't have 4 pyro outputs without an addon board. It doesn't do tracking without an addon board. etc etc etc
 
CarVac said:
What it cannot do is all related to size, and the need for add-ons.

It can't fit in 24mm tube. It can't use accelerometer-triggered events without an addon board. It doesn't have 4 pyro outputs without an addon board. It doesn't do tracking without an addon board. etc etc etc
Click to expand...


You're mostly correct, CarVac.

- The RRC3 will indeed fit in a 24mm tube.
- You're right, it does not have inertial triggering capability. That prospect is officially scrapped now.
- Correct again, there's only 3 outputs vs. 4 outputs (and it's a *very* functional 3rd output).
- Also correct on a standard GPS and downlink. You'll need another module.

Unsure about the ultimate fitment of the GPS/Telemetry module too...
Right now I'm using a custom built patch on my GPS board prototype that's just under an inch square.
The Downlink Module is also TBD... Realistically speaking, it's stacking up as 29mm minimum here.

The other truth here, is that not everyone requires all the elements you list for most 24mm projects, either.
"Add-ons" give you the option to buy what you want, and not pay for what you don't need or won't use.
Sure, there may be a little premium for space because of this architectural approach, but there's a practical limit to "small".
 
Will this sort of radio be ok to track a beeline radio transmitter with a yagi?
https://www.ebay.co.uk/itm/BaoFeng-UV...item27c7bdd188
Click to expand...

I have one that is very similar and it works well. The challenge is finding the connection to your antenna because most connections are larger. I was able to find the proper connection at Radio Shack. I don't know what you have in the UK that is similar, but you should be able to get it somewhere.

My radio receiver and antenna cost me approx. $80. The antenna was made with a 1/2" x 1/2" ash dowel with brass rods as recommended in the BRB plans. My oldest son is a computer engineering major at Clarkson University and he figured out how to install a potentiometer which gives me gain control so that as I get closer to the rocket I can weaken the reception. That modification helps me to get within 30'-40' of it or so. At that point, unless you are in 8' high cornfields, you can visually find it. The handle is made with tennis racquet tape and it is very cushionny.

I've been able to find rockets in corn fields with this set up. I imagine there is better, but not for the price.

Receiver and Yagi.jpg
 
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EeebeeE said:
I have one that is very similar and it works well. The challenge is finding the connection to your antenna because most connections are larger. I was able to find the proper connection at Radio Shack. I don't know what you have in the UK that is similar, but you should be able to get it somewhere.

My radio receiver and antenna cost me approx. $80. The antenna was made with a 1/2" x 1/2" ash dowel with brass rods as recommended in the BRB plans. My oldest son is a computer engineering major at Clarkson University and he figured out how to install a potentiometer which gives me gain control so that as I get closer to the rocket I can weaken the reception. That modification helps me to get within 30'-40' of it or so. At that point, unless you are in 8' high cornfields, you can visually find it. The handle is made with tennis racquet tape and it is very cushionny.

I've been able to find rockets in corn fields with this set up. I imagine there is better, but not for the price.

View attachment 120935
Click to expand...

EeebeeE,

Could you share some more specifics/details about your setup? I am most interested in which receiver and which BRB transmitter you are using.

Last weekend my father in law gave me his Baofeng UV5R because he couldn't use it for his purposes and I would love to be able to use it for rocketry retrieval purposes.

Cor
 
The radio is a Baofeng UV-3R transceiver. I use a BRB Beeline transmitter in my rocket. The antenna is a BRB design built with brass rods. I cannot remember the potentiometer range at radio shack but it was in the 10K Ohm range. The variable gain isn't that great. It has more of a low, middle, high feel to it. I was also able to buy the antenna connection cable at radio shack as well.

Plans for the antenna can be found here. https://www.nr6ca.org/70cmyagi.html

Last summer I had a rocket land a mile away and even on the ground the antenna picked up the signal and showed two bars on my transceiver. It landed in some very high corn and I was able to track right to it.
 
Evan,

Thanks for that information.

I am assuming that the signal meter on the UV-3R actually works as expected. It appears that the signal meter on the UV-5R either shows no bars or full bars regardless of what the actual signal strength is...

I think that is pretty much a deal-breaker as far as trying to use the UV-5R that my father in law gave me unless I get one of the BRB GPS transmitters...

Thanks again,

Cor
 
Hi Derek,

Looks like a great bit of kit and you sound like a very clever guy, this kind of project is way out of my league although I love the concept and would certainly consider buying one if in production
 
cruiten said:
Evan,

Thanks for that information.

I am assuming that the signal meter on the UV-3R actually works as expected. It appears that the signal meter on the UV-5R either shows no bars or full bars regardless of what the actual signal strength is...

I think that is pretty much a deal-breaker as far as trying to use the UV-5R that my father in law gave me unless I get one of the BRB GPS transmitters...

Thanks again,

Cor
Click to expand...

The 3R does show signal strength although you do have to wait about 15 Sec. For accuracy And to be clear...this is NOT a GPS system. Also depending on country you may need a radio license. In the US you need an amateur license.
 
EeebeeE said:
The 3R does show signal strength although you do have to wait about 15 Sec. For accuracy And to be clear...this is NOT a GPS system. Also depending on country you may need a radio license. In the US you need an amateur license.
Click to expand...

Evan,

Thanks again. I realize that you don't have a GPS system and that is why your setup is appealing to me because most GPS based systems are much more expensive than the "simple" transmitters.

Since the UV-5R does not have a functioning signal meter to indicate signal strength I am assuming that it will not be well suited for locating rockets. I mentioned that I would probably be able to use the UV-5R if I had a GPS transmitter because then I would not use the receiver to locate the rocket by its signal characteristics, but rather by the GPS locations transmitted by the transmitter.

I am planning to take my Technician exam this Sunday so that I can officially start playing...

Take care,

Cor
 
I should add that you need to ground test your system for its effectiveness before you put a transmitter and other costly electronics in a rocket and send them skyward. Our groundtesting included both long range and close-up testing. Test it between buildings, near chain-link fences that can screw with signals, and other situations you may encounter when you are looking for a rocket after it lands. Test using your body as a shield. It takes a little getting used to to figure out the intricacies of your system.

Also remember that when a rocket is in the air, the transmitter signal is much stronger. When it lands, the signal weakens. This setup will help you until your rocket is between a mile and a mile and a half away.

Finally, make sure that your transmitter frequency is not the same as that of someone else at the launch. Not only might you find the wrong rocket, but if the two are close enough to each other, the signals will interact with each other and create a more complicated signal pattern, amplifying the signal in one direction, cancelling it out in another, making it harder for both of you to find your rockets.

Best of luck to you, sir. The best rocket is one that flies well, is found, and is able to fly again. Last year, our club hosted the NAR National Sport Launch and we were very fortunate to have a Japanese couple come halfway around the world and fly some beautifully built and intricately decorated rockets. Hopefully, one day you can cross the pond and fly with us as well.
 
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