Hi
I want to use LoRa to transmit data from a high altitude balloon. I'm new to this, so I am trying to do this in the simplest way possible.
Can I use 2 of these shields to communicate over extreme ranges? I like them as they are compatible with this library.
One last thing: Can I use this without a license? Is it less than 10mW?
Hi bestanamnetnogons,
You will find in this link every answer you are looking for about Lora solutions (I guess) :
bestanamnetnogonsin:
HiI want to use LoRa to transmit data from a high altitude balloon. I'm new to this, so I am trying to do this in the simplest way possible.
Can I use 2 of these shields to communicate over extreme ranges? I like them as they are compatible with this library.
One last thing: Can I use this without a license? Is it less than 10mW?
You could use those shields, although the LoRa tracker PCBs here are a lot smaller;
http://www.loratracker.uk/?page_id=68
A tracker build requiring a lot of loose wires is not going to be very reliable.
The simplest LoRa HAB tracker transmitter is probably this, just add a GPS, the Arduino Pro Mini is mounted on the back;
10mW of LoRa is plenty for tracking balloons, you should get 400km plus with something like a 5dB gain omni base station antenna.
The HAB software on the http://www.loratracker.uk/ site does include the transmitter and basic receiver software, but a far more capable and easy build receiver based on an Arduino DUE is nearing completion;
I shall definitely consider those other, smaller trackers.
So, just for the record, the (big) shield would definitely work? Is it license except?
bestanamnetnogonsin:
I shall definitely consider those other, smaller trackers.So, just for the record, the (big) shield would definitely work? Is it license except?
You would expect it to, but as I dont have one so I cannot say for definite.
The www.loratracker.uk web site contains links to my fully working HAB tracker code. It has links into the Spacenear tracking system and Bluetooth link to an Android mapping application. It will even do FSK RTTY if you insist. Remote control of the remote tracker is included.
Its not the shield or PCB that is license exempt, its how you use and setup the LoRa, frequencies, power duty cycle etc.
With the shield you linked to, be aware that it was for the 868Mhz band only.
If you want licence exempt use you need to use the permitted ISM band for your part of the World.
434Mhz is by far the best band if you can use it, but in some parts of the World you will need to use 868Mhz or 915Mhz LoRa devices.
Well, as it turns out they luckily have a 433 MHZ version too. But thanks for pointing that out!
Its not the shield or PCB that is license exempt, its how you use and setup the LoRa, frequencies, power duty cycle etc.
What I meant was more, if I use it with this library, just with all the standard settings, will it use more than the license except 10 mW?
On the shield-producers wiki I found this: "+20 dBm - 100 mW constant RF output vs."
However I'm unsure of what that means... (I'm sorry if its a stupid question)
Or could you even use more than 10mW, as LoRa is not a classical analog radio?
The LoRa modules on the shield are limited to 17dbM, 50mW.
The Library you linked to defaults to 17dBm, easy to find if you read the notes.
For High Altitude Balloon tracking, I cannot see that you would need more then 10mW anyway, that power has plenty of range, but then the LoRa settings (and likely range) would vary depending on the data rate used, and what you mean by 'transmit data'.
There is quite a lot of work involved in going from a simple send and receive of LoRa packets to a fully working HAB tracker application, especially if you want to implement interactive remote control, upload to the Internet based tracking systems and PC\Android based mapping applications.
Yes I am noticing that... But I think I'm starting to get my head around it. So both the small tracker and the shield should work as a Transmitter.
But how about receiving the signal? Will just using another arduino do, or do I need a better receiver (like a radio or so)? Would the arduino+shield work as a receiver?
The LoRa devices are tranceivers, transmitter and receiver, so any of the shields or PCBs for transmitters will work as receiver.
Watch some shields though, they may be 5V and just about everything you might want to connect, displays, bluetooth, Wifi, GPSs, sensors are 3V3. So you can see why I stuck with 3V3 Pro Minis and Arduino DUEs.
For an Introduction to the subject of tracking with LoRa, you can read these, the KISS document describes some of the first testing of LoRa for long distance, Semtech were quite surprised;
Semtech LoRa Transceivers – a KISS approach to Long Range Data Telemetry - January 2015
Long Distance Tracking and Monitoring with LoRa - Introduction - March 2016
Part 2 – Building a Tracker Transmitter
Part 3 – Building a Tracker Receiver
Part 4 - Transmitter and Receiver options
Self Tracking with LoRa - Bluetooth to Android
Thanks for your answers! I have now come quite far with my project. One last question: Most people do not seem to transmit a lot of data from their HABs. Is there any specific reason for that?
Meaning: Would there be a problem to transmit a (not overly long) string of data (exceeding just GPS coordinates) with LoRa?
Do not assume that you can transmit as much data as you like.
For license exempt ISM band use there will be restrictions on frequency, duty cycle (% of time you can transmit) and bandwidth you can use.
LoRa is being used to transmit pictures here in the UK, using a suitable frequency of course.
You would need to check the regulations for your part of the World for details.
Do not assume that you can transmit as much data as you like. For license exempt ISM band use there will be restrictions on frequency, duty cycle (% of time you can transmit) and bandwidth you can use.
Of course. And I did not. But what I meant was more why so many HAB guys only transmit the GPS coordinates of the balloon, and not more of their data? And I don't think duty cycle or so should be a problem. After all I would only transmit a string approximately as long as this sentence every 10 minutes or so... Right?
Only sending GPS co-ordinates may be the case for APRS transmitters, but most of the LoRa ones typically send a CSV style string, with Payload ID, Sequence, Time, GPS, Temp, Pressure, status, etc.
Most often sent at between 15sec and 60 sec intervals, frequent position updates are very helpful as the balloons comes in to land fairly quickly after bursting.