Received transmissions error

Hi,

on a new gateway I’ve just set up I see received transmissions that are indicated with “error” in my gateway’s log (my hardware’s log, not on TTN.) These transmissions are all using SF7, while my own (successfully forwarded) messages are always using SF9. I can see the message type (join-request, data up/down), but apparently my gateway can’t forward them.

Are these messages genuine errors (which I need to fix), or are they just messages using another network besides TTN (which are perfectly normal to see)?

My gateway should be able receive all transmissions regardless of SF, no matter whether they are SF7 or SF9, shouldn’t it?

Regards

There’s quite a lot of detail missing here, so wild guess, they are LoRa transmissions that fail CRC - hopefully your unknown make and unknown model of gateway is saying more than ‘error’.

So, random idea, yes, it may well be devices for another network.

It’s unlikely that if it can hear SF7 & 9 that it can’t then hear the other SF’s due to the way the hardware & firmware works.

I hope not, do you not have ADR turned on? It saves bandwidth, power and puppies.

If they were - would I still be able to see the type of the message (“join”, “data” etc.)? Wouldn’t the message then be completly unreadable, including its header?

Thanks.

Well, I haven’t turned anything OFF. But I never noticed anything about my gateway or my devices even mentioning ADR. (I haven’t created my devices myself, if that was the question. I’m using off-the-shelf hardware.)

Regards

EDIT:

Oh my, of course you’re absolutely correct about the source of the errors. The “error” statement is presented in, you guessed it, the column named “CRC”. Sorry about that! :slight_smile:

But what does this mean now? Is it a reception error or a message not for TTN?

More mystery electronics, so can’t comment really, but using my :crystal_ball: I see that the majority of devices have ADR as it keeps kittens safe so it’s hard to say what’s going on.

It means that the message CRC doesn’t match what the radio heard. It could be for TTN but no one will ever know because the messages were scrambled. Things like CRC are pretty fundamental stuff to radio comms, so I’d strongly recommend you read the entire of the Learn section (linked at the top of the page) so that you’ve got the core concepts.

Do other networks use the same message header that TTN does? If my router indicates a message type of “join-request”, is this even true or is there simply a value of X at offset Y, that would indicate a “join-request” if it were destined for TTN, but since it is not, it can be anything?

Not really. They all use the LoRaWAN spec. A subtle but important distinction.

Things like the LoRaWAN spec are pretty fundamental stuff, so I’d strongly recommend you read the entire of the Learn section (linked at the top of the page) so that you’ve got the core concepts.

Please don’t take this the wrong way, but I will not do that. I will not read hundreds of pages of a specification that may or may not answer my question.

Instead, since you surely already consumed all those documents, I’d kindly ask you for some very specific information which I’m sure you have right at hand. If you can’t be bothered, I understand that and no hard feelings.

No one suggested you read the 90 pages of the spec, but you’ve asked two questions that are pre-requisites to successful implementation and I directed you to one evening’s reading that covers the fundamentals so you can make more progress faster. And even if I had directed you to read those 90 pages, it would be because they would answer your question, even I’m not that much of a dick. Look at my profile, there’s a reasonable chance I know what I’m doing, so 95% of the time I’m dishing up good stuff, the other 7% of the time it’s down to poor maths.

Please don’t take this the wrong way, but it’s all volunteers answering here who have no obligation to answer, particularly answering basic questions that can be answered via forum search or reading the Learn materials or the documentation or the specification.

If we spend our time answering the FAQ’s, we’d have no time to help those with the more interesting knotty problems that need some group thinking to solve.

And as a volunteer that learnt LoRaWAN the easy way / properly, I’m not inclined towards offering a fast food service to those that will inevitably come back to ask another question and another question. It’s not a good use of a scarce resource and it leaves you with a patchy understanding of something that is somewhat detailed.

You got an answer in the first instance with a recommendation to look at the Learn section, that’s being given the Fishing for Beginners handout, because if you give someone a fish, you feed them for a day, teach them to fish and you feed them for life. Same applies here, read the Learn section and you’ll be all set. Or not and get a version of “read the Learn section” each time.

What are reported RSSI and SNR of the packets that have CRC errors ?

My question boiled down to:

“Does a LoRa transmission (vs. a LoRaWAN transmission) necessarily have the same header as a message intended for TTN, does it even have a CRC field, or am I looking at the interpretation of random noise?”

If I failed to ask the question succinctly enough, then that’s on me and I’d appreciate the hint.

I don’t expect to find this kind of question in any tutorial. I can draw my conclusions, but I would not get the positive answer I was looking for.

That’s why I’m happy you responded to my question. I shall always defer to the advice of an expert.

Which was what I was looking for with my forum post in the first place. A RTFM doesn’t help me, even if it is from an expert.

What you could have said instead: “Are you by any chance using a Mikrotik gateway? Look in the sub-forum, that issue has been discussed before.”

Now, THAT would have been helpful (and a whole lot both quicker for you and easier for me.)

Well, that didn’t work so great, did it? Instead, you - frankly speaking - offended me by treating me like a noob. Advising me to research on CRCs was - a bit much, shall we say.

When I trouble someone by asking a question, that means that I was unable to find an answer myself. It doesn’t mean I never looked into the problem myself before that.

I really need to stress this point: I ask the question from an expert (you) because your answer would be better than what I could get from any text. I don’t ask you because it is faster.

Regards

They are low, but not that low either: RSSI in the upper nineties, SNR between -10 and -13 dBm.

I since found that it is a “speciality” of Mikrotik gateways to interpret the uninterpretable, even random noise, so it’s perfectly normal to see those errors.

Do you really expect volunteers to have a crystal ball? There are tens, if not low hundreds, of brands of gateways, all with different user interfaces and some get different user interfaces with firmware upgrades. You happen to know what hardware you are using, for us it might be anything. So basically we need to match the limited information we are given with the user interfaces we happen to know which is a guessing game.

That is not limited to mikrotik gateways, alle gateways behave that way, it is just that the user interface on those gateways makes it more visible, most gateways show this only when looking at detailed logging.

Why would you expect that we might a specific targeted (random choice of manufacturer or self build GW) question? Here we are 2 Days later we finally get a key bit of information. One of the frustrations for regular contributors and forum volunteers and moderaters is

We dont…and often end up playing a game of “20 Questions” to get the info needed to give an informed answer and one that doesnt involve refering to go read “Learn”!

An appeal to ALL potential users would be think what others might need to know to help you and over inform vs forcing a Q&A session! :slight_smile:

To expand on my colleagues responses above, two hints were given asking about which gateway and which device, answer there was none. It helps us to help you if you give us details.

And if someone isn’t familiar with how a CRC check would cause an error, then there will inevitable be some direction to some reading on the materials provided for LoRaWAN, if only to be informed how that impacts the reception of uplinks. No one accused you of being a noob and you were not advised to explicitly research CRC’s, just avail yourself of the materials on LoRaWAN.

I answered the question and then suggested you RTF-the-core-concepts to save you time asking the same questions we see time & time again on this forum because people mysteriously refuse to read the core concepts. This saves us all time, you especially. This is who I learnt about LW, by reading the docs for TTNv2, LMIC, building a node and searching the forum. I didn’t post for three months, didn’t need to.

There is no planet that asking if you have a particular brand of gateway would help as all of them that use the Packet Forwarder will report the CRC errors every 30 seconds or so.

Again, for reinforcement, you got an answer within the confines of the information you provided and were then advised to read the Learn materials. You were not denied the information, which you appear to imply you were, only that as a matter of routine for anyone asking LW 101 questions, were directed to the Learn materials for your own good so that you are better able to research & resolve issues yourself.

This is how we roll here, we have an expectation that people read the Learn section to understand the basics of LW concepts and that if they have questions they provide more rather than less information. It is also useful if they use known good hardware - gateway & device(s) = to get a simple setup running, as that fills in many of the blanks. And that they search the forum for the keywords for the situation at hand as many many questions are repeated, for instance with only the keyword CRC:

This enables the volunteers to concentrate on the more intricate issues.

I have no turf to defend here. I am out’a here just as fast as I came in.

What you need to decide: You got my feedback. Do you want to consider it and possibly make this place better for helping people or will you settle on “nah, it’s all his fault” and keep patting each other on the back for a job well done?

Which is one of the common problems, people hit and run, expecting a quick answer, tapping in to the efforts of others without hanging around to answer any other questions or contributing to discussions.

Your feedback has been heard. You are making the assumption that it will contribute to making this a better place, a place you are just passing through and haven’t spent any time in. What you appear to mean is that you’d like us to behave per your requirements. What about the regulars here, what about their requirements?

No one said anything was your fault, you were just encouraged to expand your knowledge, mostly because there were apparent gaps in your understanding of LW fundamentals.

I read these sorts of discussions / feedback on other major forums and the general theme is the same. People need answers fast, they post on a forum and then expect if not demand that the free help is formatted to suit their situation. They then disappear, only returning to do it all over again, making no contribution to the community they’ve raided each time.

Even the agreements I have with paying clients for support don’t run to on-demand answers without followup. If someone needs an answer on a critical timescale then it is provided and a training assessment performed. If there is time, then directions to resources with some facilitation to allow the developer to become more self-service &/or fill in gaps in knowledge is provided.

It is unfathomable that people can expect to make use of experts time for free when it suits them without any effort beyond their opening post just because it’s technical without some quid-pro-quo. This won’t work for your OB-GYN or car mechanic or financial advisor or building contractor, so expecting advice on tap your way is just a little other worldly. It’s made all the more disingenuous that you are using a full LNS without having to pay for it.

If are more than welcome to ask other technical questions, please ensure that they aren’t covered by the Learn section, the documentation or a forum search, as if they are likely answered by those materials, you will be directed to them as part of the response. Also consider what would be the appropriate information to include in your opening topic - settings, make & model of hardware, code, device serial debug, console info etc.

This is the first time that I hear you conceding that there actually might be a problem here.

The simple fact that I’m still writing should demonstrate that I’d rather NOT be out. I am, however, interested in the technology, I’m not interested in discussions about who has his toes being stepped on.

Also, I’ve expressed on multiple occasions that I both respect those who are dealing with the system longer than I have, and do appreciate the time they’re putting in on this forum.

What I am saying is that something went wrong and came this close to activly chasing me away. It would have been much easier for me to stay quiet and leave than to give honest feedback.

Oh, we know there are a whole raft of problems, the least of which is that on average there are only about three regulars checking in every day. This occurs on most of the mainstream forums proportional to the size of the community.

I completely get what you are saying & where you are coming from. But if we provide a quick answers service we won’t develop the community (which is what this forum is all about) and it won’t be sustainable for the few that can give reasonably useful answers. They can’t possibly answer all the questions, so the feed a fish principal comes in to play.

As this topic of supporting a highly complex subject has a direct bearing on my work, I spend time looking at how the other big forums work and I see things are pretty similar, except Stack Overflow which will actually (temporarily) ban you before you’ve even got started if your first question is not to their guidelines.

Even the forums with paid support staff on it will direct you to additional materials at the point of asking that one “direct” question. But you can see the good will wearing thin when someone tries to use it as a remote development service because the asker just doesn’t have the fundamentals under their belt.

There is also the challenge of the content of the opening question - typically more information is needed and there are assumptions made on both sides about what is known and what kit is being used. In some instances we can’t answer properly until we know the “why” - why does the OP want to do that because it currently doesn’t make sense. We rarely achieve a win on the first 5 responses. When the questions of clarification get to post #20 I start asking people to focus as it becomes like pulling teeth but we’ve got invested in getting to an answer.

In some random ideal world the vendors with the much deeper pockets than most of us would fund more materials, graduated levels of documentation so that people don’t get in to the weeds too quickly, simpler examples and “known good” hardware recommendations.

But in return those wanting to make would have to commit to using those materials. We are all pretty good with setting up WiFi now - get out router, plug in, run wizard, done. Want to connect a device to WiFi to send sensor data - use the Arduino example HTTP Client for ESP32. Just add your WiFi name & password and you should have a working demo.

But wait, someone left the security certificate in the HTTP example - which introduces some “what’s that for” queries. And it’s a GET, so now the user has to learn what a GET is. And then they have to find a starter for the web server end. Which means they need a web server.

That’s WiFi. LoRaWAN has the potential to be somewhat easier. Setup a TTIG gateway from docs, done. Get a known good off the shelf device that is in the registry, add the EUI’s & AppKey and the device console starts showing data. Add integration to dashboard service that has some pre-built charts and you are done.

But as soon as you need to tailor the LW setup or create your own device or want to setup your own endpoint for processing uplinks, the possibilities explode from a few pages of setup to hundreds of pages of potential solutions. And then some fundamentals start cutting in - like Fresnel Zones or radiated power or duty cycles or generating valid EUI’s, or, or.

I can see that there is some sense in having an Ask Us Anything service - how would you propose that it is funded?

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