#296 Lora Propagation, Range, Antennas, and Link Budget (incl. LoRaWAN)

today's video is unusual because I will appear on stage and will talk about Laura propagation this session was taped in Hyderabad India where the Asian Laura Conference with 800 and tendance took place great see youtubers here is the guy with the Swiss accent with a new episode and fresh ideas around sensors and microcontrollers remember if you subscribe you will always sit in the first row kunal software yeah everybody probably so this is basically what I thought and this is why I concentrate today on this antenna stuff and also I want to avoid some disappointments also with Laura because if you expect 700 kilometers for every note it might not happen it might not happen so question for today what is the distance we can reach really then a little bit about the link budget because this is the base you have to understand if we talk about propagation if we talk about reach and so on the next one is throughput because many people try to come to we have it also today Wi-Fi is compared some are with Laura and stuff like that I just want to make sure that everybody understands the differences then how is the antenna design connected to the battery now not at all of course it's on one side and on the other side but you will see it is very much connected then how much reliability can we expect and what we have to pay attention but the main thing is the first one reach and here is the Lawlor system it has an input then it has transmitted it has a receiver and the output ok and in between we have air and free space now the output power of the transmitter transmitter is the first thing we have to take into account this is what we get basically to gradually since then we already start to lose things cables are huge losses on one gigahertz so we will see later on don't use cables but your transmitted directly to the antenna that is rule number one now we have antenna and antennas can have gain we will see how this is possible without power connection then we have the space loss we do this again pirate there we gain maybe antenna with the antenna on the receiver side we lose again on the cable side and the receiver master defined sensitivity and this together forms the link pouches now one thing maybe there are not only technical people from your Travis University here 3d P is a factor of two so if you gain V DB your transmitter for example has double their strength but also minus three T is only half so if you lose three P 3 P DP with a cable for example your transmitted power it's half and now you see already if your transmit power is haft you probably have to increase it and then you drain your battery of course because if you haven't increased transmitting power then you need it is your transmitter needs more power more battery power ok so let's go to the transmitter there is the output power it's the most important thing for the link budget unfortunately it is restricted by law and most suppliers accept that and they do not build modules which provide more than the allowed output power now if you are if you are a ham radio operator you can you can blast 1.5 kilo watts in the air but here it's only 100 milliwatts because it's this isn band we heard before so the the Laura modules all have a limitation of 20 DB and this is where we start with the link budget now the cable already has a lot of losses and the connectors too on the other hand Laura nodes have energy consumption and it looks like we can get 10 years of usage but of course not if you transmit all the time only if you transmit never hardly never every hour every day or something like that you get these long ranges or a long lifetimes because in sleep mode as we saw before we have only a power consumption of nano ampere but if we press the send button then it consumes milli ampair high spreading factors I don't want to explain that but then basically the transmission time is longer and we need more power battery power if the spreading factor is small like sf7 then your transmission is fast so always focus on sf7 if possible of course if you have a good antenna and the quick design then you can't go with s f7 AV of it a shitty design then of course you have to increase 2x f12 maybe and then your battery will be depleted quite fast the next thing is to receive very very important probably the most important thing in in Laura is the receiver and now these are physical laws if you want to have more capacity Shannon says you need more bandwidth more bandwidth means automatically less sensitivity and if you have less sensitivity we have also a smaller link budget now the link budgets of Wi-Fi is roughly 100 DB this is just a four point number and Laura is according the leaflet maybe it's not 168 but for sure above 160 and this is a lot we will see later on how much disease now we go to the antenna if we have a dipole which is a vertical it has a shape like that it radiates 360 degrees it does not radiate to the gods and also not to the Devils I don't know how it works here but we have this concept in Europe so they do not they do not hear what you explore what do you transmit but it's around so basically such a dipole that's a little gain over a ideal antenna which transmit everywhere if you want more we have to have a directional antenna these antennas have high gains they can go up to 15 DB stuff like that so we gain a lot of link budget there because this is part of the link budget but this is not because anything is gained it's just because it's directed so all the energy which is around in this 360 degrees in the in the dipole is directed into one direction this is how the gain is created but of course if your notes are everywhere for example then a directional antenna is not a good idea or if your notes are moving then a directional antenna is also not a good idea but if you are fixed notes and if you know where the Gateway is then a directional antenna might be a very good idea because again it increases the link project it can easily increase the range but it for sure decreases battery consumption your battery can be smaller or you have a longer life but the tension we have and the law does not limit the transmitter power it regulates the power which exits your antenna slowly antenna gain is taken into account so if you have a 20 TP for example antenna gain then you only allowed to send for to transmit with one DBM instead of 20 TVN very important to know but only on the transmitter side on the receiver side you can have as much gain as you want this is not regulated so if you want to increase your your your link budget put a and that antenna weight gain on the receiver side now we go to the space between the antennas we have of course the open space but we have also obstacles we have something which is very helpful in rural areas it's called the reflections and for example you might not believe it I think your nation was recently on the moon or very close to the moon on the moon but not in the right in the right manner but I think this is great that you've got there I mean it's really far away it's really far away and you even can use the moon to balance your signals back so you can use the moon as a reflection this is great of course not with Ebola and with you need a little bit bigger antennas but it works ok but anyway the reflections are out of frames on the other hand we have also something which is called propagation or coverage predictions and this is also an important thing I will say I will give you a free little link where everybody can do that for their own gateways over there and then we have some special cases one of it is the world record this is a special case as we will see later on now there is a physical law I don't put the law here on the on screen but the result is 60 P loss if you total the distance now this might be interesting to talk if you want to explain your wife that she does not need to be too concerned about this 5g and Wi-Fi and stuff like that because the 60 P is the same from one millimeter to two millimeters you lose 60 V and from 100 kilometres to 200 kilometres you also lose 60 V so you can imagine the first few centimeters use a lot so our wives should not be too much concerned that they will be killed by a Wi-Fi antenna or something like that I don't know if it's the case here in your country but in our country we definitely have discussions like that so this should be at least some added value for tomorrow Sunday okay the second thing is we also have 60 B rows if we double the frequency now we have to complain that he chews 868 instead of 433 because he already give away 50% more or less because 433 is half a t6 t8 but anyway there are other good decisions it's a good decision but we have to know especially if we compare with them with the wife of E and this is what I want to do now just to get a bit midi used to this link patch itself now we we heard before Lorelei's 168 for the sake of simplicity I said 166 because I'm not not good in calculations in my head just like that and Wi-Fi was 100 DB so the difference is 66 TV we know we lose 60 V half if we topple the the the the range now 66 DP is 11 times 60 P so this is 2,000 times the factor it's 2,000 times okay just to we keep it in mind then the 2400 which is usually usual Wi-Fi frequency divided by 868 is another factor - I'm an engineer I'm not the mathematician so we are we are ok with with this with these kind of calculations ok so we can hear also a factor of 2 in reach compared to Wi-Fi now if we multiply the 4 the 2000 with the 2 rakaat away as a result laura range is 4000 times longer than life on it there is a difference it's not a little bit the difference it's a huge difference and this is theoretically of course but still from a theoretical point of view we get these opportunities these opportunities and we can use them and this is also the difference between Wi-Fi so don't ask me can I replace Wi-Fi with this one it would be great but of course we saw before the bandwidth the bandwidth here is very low and we will see later on what it means now the next thing is of course obstacles obstacles our enemies and here I just have a list and you see class it's very on top and concrete is very important on the bottom so concrete for example has a loss of 35 DBS and a TV and the glass thin glass of the less than 1 DB so there is a big difference now if you put your note in a cellar or in a basement don't expect anything it might work on the street but it will not deliver this promised 700 kilometers because it's everywhere concrete now there is one caveat and this is our new and modern windows glass is also enhanced with some metal filters to prevent heat to enter and these usually are also very good filters for gigahertz and off signals so you have to track you have to try if you're if you windows is transparent or if it is also caulking then it's like the like concrete or nearly like a concrete so it doesn't help you okay then there is the reflections basically the transmitter transmitted and then a house or something can reflect the signal but of course as you see here H only very little reflection you lose a lot of TP at the point of reflection but still it can work you can't get connections where you should not get connections in rural areas but of course maybe only on 50 meters 100 meters 150 meters something like that but this is interesting as I said before they even use the move to the to balance pack now we come to open space propagation now this is Switzerland this is exactly where I live and I have a gateway on my roof and this is a prediction how far this gateway reaches it takes off into account we will see later all the physical laws of propagation and this software has a 3d model of the whole world it's interesting that there's something like that can be a provided free of charge and it works I Ted I checked it but if we look now here I live just somewhere in Switzerland and we have mountains but we have also hilly areas I live in a hilly area and the biggest distance I can reach you see here this would be the farthest the the north most far away from my gateway which would still reach the Gateway and it's only about 20 kilometers so the reach of my gateway is not more than 20 kilometers but you see many white areas which are much less than 220 kilometers and there I will not hear anything it's blocked okay but then I got 60 I'm a married man and I knew if I do not present the present to me I probably will not get one so I said I want a present for me and I give myself a world record ok so I needed something different I needed a gateway which was capable to deliver a little bit more than 20 kilometers because even at this time 3 ago so now you know how old I am fortunately I know woman so I took I took I took this propagation forecast and searched the best gateway available in Europe for this purpose and this is the gateway and this is where it sits and these tie receipts from 1500 meters on a on a reasonable Hill at least and this is a base gateway in the hole in the whole world for this kind of it is not necessary to have it as high as possible it's the difference between the gate at the gateway and under under the environment and we as we will see later on okay so I said I do a world record and this one's my device look at the antenna it's not very big so this is by the way the proof longer is not always baited this small device I was capable to do a world record at this point in time and the world record is basically land to land so both I was both work on the base and it is always possible to repeat this this connection ok so this is the gateway and this is the reach of this gateway and the difference is 200 kilometers and the proof that it worked is in JP Myers TTN mapper the guys who were in here yesterday they remember it was officially approved that that this connection took place and I even got an exception because usually JP does not map any connections above 100 kilometers because they are very rare okay now let's have a look in this what happens here so you see on the left and you see the Gateway it's on it on a reasonable Hill and on the right side right hand yeah on the right side you see where I was and you see now already the earth curvature now do we have any any flatter axis here in in in India no so that's good the earth is has a curve curvature and this is why you cannot reach to two while too far if you if you are not on a reasonable level on the other hand if you you see here for example the Fresnel zone the Fresnel zone is a physical necessity for signals to to to travel if the Fresnel zone is blocked by obstacles then news already part of your link budget even if you have line of sight they have line of sight here as you see here but that the trestle zone was half blocked so I got 16 DB loss because of this small hill there and the whole thing including everything we got a link budget of 157 DB and this is of course more than the 100 and 60 or 65 or whatever which is offered by lora and so it theoretically it should be possible to to get a connection there and this is why I sat in my car and drove to this location and it it happened it worked but 50 meters on the left and fifty meters on the right side it did not work so this is also the proof that is this model is quite accurate it's quite accurate so you can really depend on it if you do you're near propagation status now we come to the special cases one special case is the volume linnert this one went to 702 kilometers and another one obviously was 766 kilometers now with all the knowledge we have now we see that if we have a balloon of course it's no problem to get a line of sight even for 600 or 700 kilometers because the elevation of the balloon is up to 20 kilometers or something like that so the earth curvature is no problem and then the next of course is satellites and we will hear after its presentation also on satellites and satellites are even higher up under the reach there is even it's even bigger you have to you have to have a bigger reach to reach a satellite we will hear how high they they move okay but these are for me special cases because we should focus on gateways here on earth because it's much cheaper now the biggest enemy is interference from other users but fortunately it's only on the receiver side you do not have to care about the interference on the transmitter center but if you place your gateway pay attention where you place it because there otherwise you do not get a reliable communication because if you have interference your gateway does not hear anything it's like if you are in the inner discotheque with live music you cannot speak or you can speak but not listen or you do you are not understood okay so summarized if you have a line of sight in channel it's okay don't think about it if you have a line of sight it's okay Laura is good enough if you do not have a line of stunts expect that it will not work until you test it it might work it might work on a short distance it might even work on a longer distance but you have to test it use propagation forecasts for your decisions where to place your Gateway for example on water towers and stuff like that there are very good locations for for for gateways and lower to the floor is usually use this or to place the Gateway avoid antenna cables as which as we said use cables on the on the low frequency side not on the antenna sound and consider the interferences or on the receiver Center now after the two days I hope that you can decide if this is the right technology for you or if you have to go to the many other technologies which are available so thank you and my Brandon from YouTube is I'm the guy with the Swiss accent [Applause] I hope this special video was useful or at least interesting for you if true please consider supporting the channel to secure its future existence you will find the links in the description thank you bye

Channel: Andreas Spiess

Views: 34,086

Keywords: arduino, do-it-yourself, eevblog, esp32, esp32 project, esp32 tutorial, esp8266, esp8266 datasheet, esp8266 project, greatscott, guide, hack, how to, iot, lorawan, nodemcu, project, smart home, wemos, wifi, LoRa, lora range, lora propagation, gateway range, lorawan gateway, lorawan gateway antenna, lora antenna, 868MHz, 915MHz, tutorial, internet of things, esp32 external antenna, antenna, long range wifi, greatscott!, arduino tutorial, esp32 arduino, electronics, maker, espressif, ttgo

Id: BOc3N3Yl38o

Length: 25min 30sec (1530 seconds)

Published: Sun Nov 03 2019