New LoRa RF distance record

[nickcw]

LoRa runs in the 868 MHz band (in Europe) - a frequency range known for being line of sight only as the ionosphere doesn't reflect radio waves of that high frequency.

However sometimes you can get Troposheric propagation on these high frequency bands. This used to be common when I was a teenager living in the south of England in Kent and we could occasionally receive racy TV channels from Europe.

https://en.wikipedia.org/wiki/Tropospheric_propagation

From wikipedia:

> Tropospheric propagated signals travel in the part of the atmosphere adjacent to the surface and extending to some 25,000 feet (8 km). Such signals are thus directly affected by weather conditions extending over some hundreds of miles. During very settled, warm anticyclonic weather (i.e., high pressure), usually weak signals from distant transmitters improve in strength.

Radio Amateurs love this kind of propagation. It is very variable, doesn't last long, but can give you contacts over great distances on frequencies which are usually line of sight. I think the record for radio amateurs on the 70 cm band (430-440 MHz) is over 4,500 km!

[tlamponi]

> LoRa runs in the 868 MHz band (in Europe)

No, LoRa can run on two bands in Europe, either EU433 from 433.05 to 434.79 MHz or EU863 from 863 to 870 MHz.

See e.g., https://www.everythingrf.com/community/lora-frequency-in-eur... or https://www.thethingsnetwork.org/forum/t/is-there-an-agreed-... or for a more dense, but definitive source https://docdb.cept.org/download/4316 ("EUROPEAN TABLE OF FREQUENCY ALLOCATIONS AND APPLICATIONS IN THE FREQUENCY RANGE 8.3 kHz to 3000 GHz (ECA TABLE")

Albeit I'm not sure what band they used here.

[blantonl]

Just to expand upon this, tropospheric propagation happens typically where there is a temperature inversion, meaning, air near the surface is cooler than higher up in altitude. That warmer air aloft acts as a layer that radio waves bounce off of.

[dbrgn]

Could the signal bounce off airplanes as well, or is that effect not relevant in practice? (I think I've heard such stories before from radio amateurs...)

[johanstokking]

CTO & co-founder of The Things Network here! I've been working with LoRa for over eight years now, and I keep getting surprised by measurements like this. What started off as "line of sight works" went to a successful "LoRa moon bounce" [0] and now a sea level reception over 830 miles.

So, any physics people here care to comment how this works? Is this pure atmospheric refraction or is there something else?

[0] https://www.camras.nl/en/blog/2021/first-lora-message-bounce...

[femto]

To some extent it's statistics. Send enough messages and the odds are one will eventually get though.

> providing a standardized and objective measure of the technology's capabilities

Not really. The environment is still variable. A short message could have bounced off some random short duration reflector somewhere (aeroplane, meteor, lightning, ...) or have been refracted by some short term effect. Standardised and objective is an anechoic chamber or a cabled in attenuators/channel simulator.

[pmuk]

I've just disconnected a BobCat miner so I have a spare 1.1m 8.5dBi 868MHz antenna on my roof. Can you recommend a good gateway to get started on TTN?

[zikduruqe]

A CTO that doesn't understand RF and has been working with it for 8 years? <surprised Pikachu face>

[knorker]

Hi. Cool work. For this particular record, could you confirm that this was on 868MHz?

[mk_stjames]

There is never any mention of bitrate when talking about LoRa. It's infuriating from someone on the outside.

From what I gather, the map says a "SF:12" which means a spread factor of 12, at a bandwidth of 125khz. With a code rate of '1' according to https://www.rfwireless-world.com/calculators/LoRa-Data-Rate-...

this means about 292 bits-per-second transmission rate for the packet. But I'm unsure if this is correct.

How hard would it have been to put that in the post? I feel like there is some conspiracy to never talk about bitrates/transfer rates in the LoRa world. Like, ever.

Just say it. It helps people understand what this tech is for.

[wienke]

Good point. We'll add that to the next post if there is a new record. Also what can be confusing is that the business viable part is even much smaller than the technical viable part. The low power operations is really only at lower SF7 or SF8. And we push our partners and ecosystem to keep the payload as small as possible as every byte counts. It is a completely different way of thinking than WiFi or cellular. Yet I do agree it is presented with the same terms and paradigm and that is confusing.

[datadrivenangel]

You can do a lot with 292 bits per second if you use it well.

[abwizz]

fwiw lora is meant for extreme low-bw applications, like a few key-value pairs per hour.

maybe not mentioning the bitrate discourages misappropriation?

[naillo]

The things people are able to do these days with low rank approximation is crazy

[Kamshak]

no jokes allowed on HN, sorry

[sunbum]

There exists technology that ISN'T Ai...

[uoaei]

This has nothing to do with low-rank approximation.

https://en.m.wikipedia.org/wiki/LoRa

[stavros]

In the last few years, the RC market (drones, airplanes, etc) has shifted to LoRa for the control link. A tiny, battery-powered transmitter/receiver pair lets me go 50km easily, which is just amazing.

ExpressLRS has taken everything by storm, partly because it's a well-governed open source project, and it manages to innovate many times faster than the old companies manage to fix bugs in their own products.

[albertzeyer]

So I know LoRA: Low-Rank Adaptation of Large Language Models and Using LoRA for Efficient Stable Diffusion Fine-Tuning. But from the text, I don't think this is about it? It seems it's this: https://en.wikipedia.org/wiki/LoRa

[knorker]

That's right. Microsoft must have used Bing to see if the name was taken, and got no results, when they named their thing LoRA.

[dopidopHN]

Correct. It’s a low bandwidth/ long distance RF protocol over specifics bands. It’s also kinda proprietary.

[shnibu]

LoRa vs LoRA. The former is what the link is about which is some cool radio stuff.

[ricardobeat]

How does this work?

At this distance you need a 130km-high tower for line of sight due to earth’s curvature. The previous record was set on a balloon flying at 38km height. LoRa uses high frequencies so shouldn’t benefit from the ground effect?

[MrOxiMoron]

probably the same amateur radio people can connect to people halfway across the globe; bouncing off an atmospheric layer.

[catbert69]

99% this was atmospheric ducting. Also LoRa is an incredibly robust modulation.

[jacquesm]

It's a one-off, you won't be able to achieve this with any degree of reliability in practice, but it's a nice milestone achievement.

[goodpoint]

Nice, but don't forget that LoRa® LoRaWAN® and The Things Network® is all proprietary and patented stuff. The article is advertising.

[johanstokking]

This is not entirely accurate. LoRa is a patented RF technology owned by Semtech. LoRaWAN is a standard maintained by the LoRa Alliance (which is not very different from other standards and marketing bodies). The Things Network (founded by @wienke and myself) is a developer community around LoRaWAN and a free to use cloud service intended for R&D and non-commercial use cases.

[catbert69]

You can get a LoRa transmitter/receiver for like $5 and setup your own network. Documentation and datasheets are freely available. They are really not printing money with that technology.

There isn't any opensource modulation scheme that comes even close to LoRa.

[martin_a]

Yeah... But WiFi doesn't work when I'm sitting on the toilet two rooms down the corridor. Crazy times.

No, to be honest: Very impressive. It's kind of a "dream" of me, to bring Internet to the river/picknick area two kilometers away from me. LoRa would probably be the way to go, will have to look further into that.

[Springtime]

From the relatively little I understand the lower the radio frequency the lower the bandwidth but more range it has/can pass through, while conversely the higher frequency the more bandwidth but shorter range/harder to penetrate obstacles (see eg: 5G). LoRa is the former and used for very low bandwidth applications, so not really suitable for browsing websites but has been used for for remote IoT stats, text messaging, etc.

(Fwiw I wasn't the one who downvoted but thought it'd be worth mentioning)

[wienke]

For sure would be great but LoRa has limitations as it is designed for small sensors that sent very little data: https://www.thethingsnetwork.org/docs/lorawan/limitations/

[moffkalast]

Define "internet". LoRA is more like an occasional SMS service than a network connection, so I doubt you could get the average modern 100 MB website to render through it. Would be more practical to get a Starlink dish set up or a directional wifi antenna on both ends, those can do a few km on a good day.

Or just you know, use the 4G that is probably there already.

[Tepix]

LoRa has pretty strict limits on how often you may use the frequency. That severely limits use cases. Browsing the internet is completely unfeasible.

[Saris]

The difference is the 160bps they have with this isn't going to be too much fun for web browsing!

[ur-whale]

A good explanation of LoRa, and in particular of the "link budget" idea which makes LoRa different from other wireless tech:

https://www.youtube.com/watch?v=hMOwbNUpDQA&list=PL3XBzmAj53...

[jschveibinz]

More ideas to read about:

1. How to increase range: https://community.emlid.com/t/increasing-lora-s-range/32597

2. LoRA repeater: https://hackaday.com/2019/05/02/simple-self-contained-lora-r...

3. High altitude LoRA receive-transmit: https://www.daveakerman.com/?p=2828

[wienke]

Why did the moderator remove the distance? That is like the main fun message.

[boffinAudio]

Dang, so close to a truly 'lite figure for the record .. challenge accepted!

I've had a plan to blanket my city (Vienna) with LoRa and create my own local Internet, wiring up only retro computers .. seems like its time to break out the ol' lunchboxes and get cracking.

[jacquesm]

That's a neat idea. The challenge will be to stop it from becoming a huge success because then you get all of the problems that are endemic on the normal internet as well. But that sounds like a very interesting and worthwhile project.

[chronicsonic]

Cool! I had a tour a few months ago at this Telescope in Dwingeloo. Highly recommended, was amazing to hear the live sound of a pulsar (in the Crab Nebula).

[wienke]

If you want to know more Thomas Telkamp used that Telescope for a nice experiment and bounced a LoRa message on the moon: https://www.youtube.com/watch?v=nIdCzvLWCEc

[Aachen]

Are we sure it wasn't one more kilometer? Has it been rounded correctly? Curvature of the earth taken into account?

[flxh1]

Wow, why do you think this was more effective than the weather balloon? Does the water have such an impact in the signal?

[glonq]

1336km is ridiculous! I was more than satisfied to get 1% of that range on my last LoRaWAN project.

[sjkoelle]

Damn this wasn't the LoRa I was thinking of

[Phelinofist]

Nice that the title contains both, km and mi

[wienke]

km are better though :)