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Topic: Issues with LoRa module and library (Read 557 times) previous topic - next topic

edugimeno

Hi There! Im building a LoRa GPS Tracker. This is for a School HAB balloon project I'm helping the students with.
Im using a "BSFRANCE lora32u4" board. This is basically a clone for the Adafruit Lora 32U4 board.
I'm using the LoRa library that comes with the library manager

First issue I have, is that some example sketches try to initialize the LoRa interface with a call to LoRa.Begin(BAND, PABOOST), where there's a second parameter for either activate or deactivate PABOOST. Most of the libraries Im finding don't allow this second parameter, can you confirm if this is needed?

Also, my sketch is getting stuck while sending, after 3 or 4 packets. It gets caught in the middle of the call to LoRa.EndPacket (). This is something that I've found to be reported on some other threads but it looks like there's no solution for this. Some people have suggested to remove the "while..." section at the EndPacket code, but many discourage them to do so.

Has anyone had these issues with this library? Im really stuck and need a working solution to track this thing!!! :)

Thanks in advance!
Eduardo

pylon

The LoRa (exactly that name) library available in the IDE supports only one parameter (frequency) for it's begin() method. As there are almost a dozen libraries for LoRa available in the IDE, provide it's exact name and maybe the developer to identify.

srnet

#2
Mar 20, 2019, 06:03 pm Last Edit: Mar 20, 2019, 06:04 pm by srnet
Has anyone had these issues with this library? Im really stuck and need a working solution to track this thing!!!
Does rather depend on which library it is ?

If others have had problem with the library, and the author has not posted a fix (nor anyone else), perhaps use another library.

Failing after just sending 3 packets does not sound good.

Once the balloon is launched its kind of important that the code is stable, if its not, you may not get your balloon payload back.
http://www.50dollarsat.info/
http://www.loratracker.uk/

Riva

For what it's worth I use the Sandeep Mistry LoRa library here with both LoRa32u4 and Heltech ESP32Lora modules and find it works well for my needs.
Don't PM me for help as I will ignore it.

edugimeno

I've reverted to using this one:
http://bsfrance.fr/documentation/11355_LORA32U4II/BSFrance.zip
For some reason this one allows the use of the PABOOST additional parameter during Begin method. Not sure what I get here.

Quote
Once the balloon is launched its kind of important that the code is stable, if its not, you may not get your balloon payload back
Believe me this thing is not being released until I have a trustworthy sketch sending tracking updates for 6-8h at least...:)

I tried the Sandeep library too with similar results. I'm starting to suspect maybe the board is not very reliable

Also this is another SILLY issue. I have lots of antennas at home which I've been buying for years. Right now it's hard for me to tell which ones are 900Mhz or 2.4GHz... Because I've also read about people having the "stuck into EndPacket" call when the antena is missing or is not well matched....

srnet

I've reverted to using this one:
http://bsfrance.fr/documentation/11355_LORA32U4II/BSFrance.zip
For some reason this one allows the use of the PABOOST additional parameter during Begin method. Not sure what I get here.
For what reason do you 'think' you need to use PABOOST in the first place ?

The PABOOST, for modules that support it,  only 'boosts' the power from 17dBm to 20dBm, not a lot of a boost really.

Do you need such a high power as 20dBm (100mW) ?

A lower power of 14dBm (25mW) of LoRa will get you 700km+ range, ground to high altitude balloon, do you really need  more ?

   
http://www.50dollarsat.info/
http://www.loratracker.uk/

freaklabs

I would say if the full power is available (20 dBm), might as well crank it up there. As long as you have good power management, the additional energy it takes is not so much.
FreakLabs
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Riva

I tried the Sandeep library too with similar results. I'm starting to suspect maybe the board is not very reliable

Also this is another SILLY issue. I have lots of antennas at home which I've been buying for years. Right now it's hard for me to tell which ones are 900Mhz or 2.4GHz... Because I've also read about people having the "stuck into EndPacket" call when the antena is missing or is not well matched....
I may be miss representing this but I feel I have read somewhere that powering LoRa without an antenna (or the wrong frequency) damages them very easily.
Powering any transmitter without a matched antenna can cause problems/damage but maybe LoRa takes it hard.
Don't PM me for help as I will ignore it.

srnet

#8
Mar 21, 2019, 09:26 am Last Edit: Mar 21, 2019, 09:29 am by srnet
I would say if the full power is available (20 dBm), might as well crank it up there. As long as you have good power management, the additional energy it takes is not so much.
If you only need 1dBm for an application, then use that.

Using excess power, whether legal or not, causes unecessary interferance, being considerate to other users of the spectrum is surely a good idea ?

In the UK LoRa is now often used for tracking high altitdude balloons, we are restricted by regulation to 10mW, but with LoRa no more than that is required, its good for many hundreds of km.
http://www.50dollarsat.info/
http://www.loratracker.uk/

srnet

I may be miss representing this but I feel I have read somewhere that powering LoRa without an antenna (or the wrong frequency) damages them very easily.
Powering any transmitter without a matched antenna can cause problems/damage but maybe LoRa takes it hard.
No its true.

I have damadged quite a few in my time, I dont think they are more likley to be damadged than other RF modules, but they dont like transmitting with no\poor antennas. 
http://www.50dollarsat.info/
http://www.loratracker.uk/

edugimeno

For what reason do you 'think' you need to use PABOOST in the first place ?

The PABOOST, for modules that support it,  only 'boosts' the power from 17dBm to 20dBm, not a lot of a boost really.

Do you need such a high power as 20dBm (100mW) ?

A lower power of 14dBm (25mW) of LoRa will get you 700km+ range, ground to high altitude balloon, do you really need  more ?

   
I've used LoRa may times in different projects, I've always used base power and SF=6 or 7.
If there's a project where I believe that full power is required is this one. This balloon may travel 150-250Km assuming normal weather conditions. We may lose its signal during "landing" and may have to search it again when it's already on the ground, starting from a distance that might be far away. And this project will only last 4-6h in total, that its full life, so that's the maximum time it will intefere with the rest of the world. After we recover the payload, it won't transmit again.

Believe me this is the only situation when I would go for the max power available. Those extra db may make the difference between losing the payload forever or recovering it

edugimeno

I may be miss representing this but I feel I have read somewhere that powering LoRa without an antenna (or the wrong frequency) damages them very easily.
Powering any transmitter without a matched antenna can cause problems/damage but maybe LoRa takes it hard.

That's absolutely true, I am also a radio amateur and have worked a lot with SWR and antenna matching, ham radios get their final transistors destroyed in seconds while transmitting with a unmatched antenna or without antenna. TBH smaller power radios are less prone to failing in these conditions, but there's still a probability.

In my case, I know that I've had the Tx section ON for some small time and so far I've been lucky and not destroyed any.

In any case, it would destroy the RF-Out section for the module, but I believe the logic that "talks" to the library would still be alive.

These modules in particular do work, I upload the basic Lora_Send and Lora_receive, take them apart several hundred meters and they work flawlesly. It's when I make my program more complicated when things start to work randomly...

srnet

Problem with high altitude balloons is the size of interference foot print they can create. Use full power and the signal will cover an area of around 1 million square kilometers. The same transmitter on the ground would only cause same issues over maybe 5 square kilometres.

The requirements for in flight tracking are threfore very different to the requirements for ground range searching. When the balloon has stopped moving, flip to higher power (if needed) and SF12, you will then have the range you need for ground searching, without the need for excessive power in flight.
http://www.50dollarsat.info/
http://www.loratracker.uk/

edugimeno

The requirements for in flight tracking are threfore very different to the requirements for ground range searching. When the balloon has stopped moving, flip to higher power (if needed) and SF12, you will then have the range you need for ground searching, without the need for excessive power in flight.
That's a good idea.
Anyone, I don't have any experience with LoRa out of the Ground-to-Ground scheme. And I'm getting distances of 6-10Km depending on the scenario.
Now talking about Air-to-Ground. Do you know, for a fact, that I will be able to pick these signals with no issue, even when the ballonn has already moved 100 km away, from the ground, at SF=7 with no problem? I don't have any way to test this other than risking to lose all the payload if I happen to actually lose the signal...

Thanks

edugimeno

Ok there's definitely something different on these boards.
Some days ago I started all my tests again with "basic" parameters, just in case:

SF=7
No CRC
No SyncWord
NO PABOOST

Today I kept experiencing the random loss of signal in the receiving lora device, even at short distances, of 3-5 ft
I added the RSSI measurement to the debug output in the RX. This surprised me:

At 3ft distance between antennas, I was getting RSSI of -125 to -135, and half of the times the payload was garbled

That's why I started suspecting my antennas. Because I have a bunch of them from older projects and I wasn't sure if they were 0.9 or 2.4GHz. So I removed the antennas, and soldered a 8.6cm wire to the ant pad, as this is a method that I've used in the past with very good range results

Still, no change. Same poor RSSI. Tried other BSFrance boards I have at home, both in the Tx and Rx side. No change. Tried these other boards with the wire antenna too. No change

Tried to re-activate PA BOOST.

BIG CHANGE. Rssi came down to -40 at short distance. -70 at opposite ends of the house.
Tried the subber antenna. Same result (So I guess they were valid).
So this makes me wonder why the power on this devices is so low until I activate the PA BOOST parameter.

Can any one explain what it does? Anything else than "unlocking" a higher power? Or does it change anything else?

Anyway I see that Im going to "fly" with this PABOOST parameter ON

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