How to Get MORE Radio Range

title to this video feels a little click baity to me uh since all we're talking about is RF propagation but then again the only reason to understand our propagation is to uh get your radio communications to go further now technically you don't always want your signal to go further sometimes you just want it to go to specific places but more range is generally something that is desired now whenever you buy these blister pack radios from Walmart F FRS radios they always say on the packaging 35 mile range which you have probably never actually experienced now theoretically it is technically possible depending on you know how honest the radio manufacturers are but if you were able to get two radios 35 M apart perfect line of sight absolutely nothing in the way it is theoretically possible getting nothing in the way is a bit of an issue and that's mostly we're going to be talking about in the video but the antenna is also a big factor so much so that I'm going to talk about that first and my brother David came out with a really good analogy an LED flashlight transmits light now in the past flashlights did not have LEDs they had incandescent bulbs and when you put one watt of electricity into an incandescent bul you did not get a Watts worth of visible photons you got a lot of heat and you got a little bit of visible photons LEDs are much more efficient you get way closer to one watt of actual light out of that led and that's a little bit like having a high gain antenna an antenna that very efficiently turns all of the RF energy that comes out of the battery of the radio into RF signal that goes somewhere but most of these antennas are are omnidirectional antennas they send power out in 360° now that's almost what this led is doing here it's got a little bit of directionality to it because of the tiny lens that's on the very front there but there's also quite a bit that comes out the sides so the light that it actually puts on my face is not much and the rest of it's going around the room once you put a reflector behind that LED on the other hand you get considerably more power from basically the same brightness now you have way more power actually on the place where you want to send your signal and that's why directional antennas even for small handels like these can have a massive effect on how far you can reach and who can actually hear your transmissions and it also lets you control who can't so think about directional antennas as you focus focus on this uh it just makes perfect mathematical sense if you have a 360° omnidirectional antenna you could get 10 times the power on the Target that you want just by narrowing it down to 36° the only problem with that is you got to know where you are and you got to know where the guy that you're talking to is so that you can point the directional antenna at him otherwise he's technically getting less power than if you had the 360° omnidirectional and antenna but there are so many other factors that go into where the signal goes and how far and that is what is it going to be blocked by what is it going to be reflected by and then there's the fact that different radio frequencies are affected by different materials in different ways and so I found myself wishing recently that I could get my hands on an RF simulator something that would calculate the RF propagation and attenuation of signals in three-dimensional space and that kind of sort of exists in fact there are tools uh that sort of figure that out for attac uh for caltopo for some other mapping tools but I wanted something that was a little bit more colorful and a little bit better as a teaching tool and my brother David got me thinking since RF does behave a little bit like light why not use a light simulator to figure out what radio waves are doing this is LightWave 3D an animation package which has a really good uh Ray Tracer inside and the same engine that can R trce light beams shining around are going to allow us to simulate radio waves if I rotate the sun around in this particular scene you can see how it's casting a shadow on this guy here but there's so much light bouncing off the side of this house that he is still illuminated even though he gets Shadow on this side so there's a lot of cool stuff that we can do with this admittedly ancient piece of software here now I apologize in advance for the crudity of this model I didn't have time to build it to scale or to paint it but we do have a couple of interesting props here we're going to start out with this very simple scene here that has trees leaves the ground and a building which is constructed out of a couple of different building material and we're going to talk about radio waves across this spectrum here over here we have the very high frequencies are not called very high frequencies they're just called uh 2.4 GHz Wi-Fi and then all the way down to HF frequencies they're the high frequencies but they're on the lower end of the scale that we're going to discuss so let's talk about WiFi first because it's probably what you have in your house and you probably have a rough idea of how the signal drops off as you walk around and go outside this purple signal is the Wi-Fi inside of the house and as you can see it actually comes out through some of the building materials you're actually able to get a pretty good idea of what is blocking that Wi-Fi signal and what is actually allowing it to get out through the walls of the house but most of the signal is coming out through this open door here an Open Door there and some windows and as we zoom out even more we can see turn up the signal a little brighter so it's easier everywhere that you can see a little bit of purple is where a little bit of Wi-Fi is escaping weak signal and then the bright pink areas are where it is a much stronger signal and if you are a phone say you have a Wi-Fi radio in your phone anywhere that is along here being illuminated by that RF signal which being simulated by pink light purple light you will be able to get signal stronger where it is brighter weaker out here and there's only a few places that are really being fully illuminated and there are certain objects that do a much better job at blocking that signal than other the leaves of trees because they have so much water in them actually attenuate that signal very quickly and this is only 2.4 GHz Wi-Fi you know there's 5 GHz Wi-Fi and then there's like much much higher uh frequency 5G which is so high frequency that almost behaves like actual light where a single leaf can block that signal this is getting through some leaves but uh as you can see here leaves are blocking it better than twigs and drywall now let's turn this wi-fi off and let's turn on uh this UHF radio IO which is hovering above our guy's head let's bring that down a little bit closer to where he is as you can see this lower frequency signal is going through the leaves just a little bit more effectively here the UHF signal is also doing a better job at going through the house uh the studs are blocking a fair amount of this signal here but there's still some that's actually getting through the building so you'd be able to detect it on the other side now if we zoom out we can see where the signal is going in the landscape and this is what most of the RF propagation simulators are going to do they're going to look at the three-dimensional terrain you're going to tell it where the radio is and it's going to figure out which pieces of terrain are being blocked uh from a receiving signal by other pieces of terrain and there's obviously other stuff that's going on there are buildings there are foliage but terrain is really the big one and so you can see right here just by elevating this walkie-talkie the signal covers a much larger area of the map if you are able to get to a higher point of the map or attach the radio to say a flying drone you have signal in a lot more areas and you're able to get over the top of a lot more of the obstacles but there isn't just signal being blocked and absorbed by stuff there's also Reflections and for that uh we're going to go look inside of this particular cityscape here move our radio into these buildings here all right as you can see we've got some pretty hefty buildings around and these are generally made out of concrete and they're made out of steel and they're made out of glass all of which have different characterist ICS when it comes to radio propagation and again it varies based on band but right now we're talking about that UHF band and so in addition uh to going through more materials than say WiFi it is still reflecting off of a bunch of things so even though let's say we were standing right here inside of this Shadow it is impossible for us to see the signal coming directly from the other side of the building but you can see that the signal is is being reflected off of other buildings so if we have a clear path over here we will actually be able to get some level of signal and this is where having a slightly more complicated Ray tracing and Global illumination engine is actually helpful we can see here a little bit of light is bouncing all the way off of these other buildings into this little pocket here now it's not much signal but theoretically we could pick up a little bit of something even back here in this dark corner simply because of Reflections that are happening a lot of the RF simulators don't calculate quite as many bounces and so having a tool that does is just kind of interesting to play with again this is this is uh an artist interpretation here it's not actually how every single radio is going to perform in every single type of City scenario but uh it is it is interesting interesting to mess with here's another pretty good example we can see that this building is casting a shadow that no signal is getting into directly from the radio but the light is bouncing off of this part of the building and it's getting up inside of here and bouncing off of that building as well so there's signal even inside of this Shadow so that's an interesting characteristic of UHF radios now let's look at VHF radios so we are no longer 44 MHz is we're going to closer to 150 MHz is this is a longer wavelength which in theory should give us better penetration and better distance turn off our UHF transmitter turn on our VHF transmitter okay so now we're seeing something kind of interesting yes we are getting a little bit more penetration there's a little bit of signal over here is actually penetrating through mostly I think these windows but one thing that we're seeing is a little bit less Bounce U I'm not simulating this 100% perfectly accurately but uh you're getting some of the signal not bouncing as well because it gets into the building and then it gets absorbed by other stuff that is inside of the building as opposed to Simply bouncing off of the outside now let's say that we were a little further away from the city let's say we were standing on this Ridge line here and of course we cannot see the radio that's hidden behind these buildings but there is still a little bit of reflection off of these other buildings and we can also see some spill coming off of the ground itself some radio waves will bounce off of Regular ground but it kind of depends on soil composition how wet the ground is and some other factors uh also VHF skips very nicely over uh oceans and other bodies of water but it likes salt water uh for transmission and skipping along better than fresh water so yeah lots of variables but VHF does do better than UHF in the forest so uh let's head there now man why is this taking so long LightWave 3D is uh not the world's most advanced animation engine and I've got to admit it's starting to show its age a little bit okay right now we have our handheld radio on its VHF frequency inside of this little Valley and as we remove the camera we can see that that signal is in fact penetrating through a lot of leaves uh once we get enough foliage in the way it is going to block the signal but it's doing better at cutting through it than some of those shorter frequencies and like all other radio waves that we've talked about if we can just move to get on top of a ridge line we can now get our signal into a couple of different valys and cover a much larger area so terrain masking is something that you'll hear people talk about from an electronic warfare perspective uh but it's really just basic obsc if you know that there's people on the other side of the this hill that you don't want to hear your signals getting on this side of the hill so that your signal is blocked in that direction is going to help you out quite a bit but uh you also want to position yourself so that you can get your signal onto the areas where your own guys are or whoever it is that you are trying to communicate and as long as you can get enough elevation and you can get a clear line of sight or at least a roughly clear shot in the direction that you're going to go you can hit the other sides of hills and we're also hitting the other side of this hill a little bit with some faint signal so yeah we're now seeing uh a pretty good idea of where our signal is going to go based on where we put our radio and these different frequencies but what if you wanted to broadcast excuse me transmit more broadly what if you wanted to reach not just from Hilltop to Hilltop not just from Valley to the other part of the valley not just reflect your signal off of a couple of buildings but what if you wanted to talk to people who were really far away well the simulator starts to break down at that point because now we're talking about HF radio uh what is known as high frequency radio now technically it's much lower frequency than anything we have been doing before and it's where the radio waves start to behave like something other than light actually that's not entirely true the radio waves still want to act like light but the objects stop acting like objects the radio waves go through all kinds of stuff and then there's other objects uh that are not objects at all that start behaving like objects all right let's turn off our VHF signal here Crank that down and let's turn on our HF signal now this HF signal right off of the bat you can see that it is spreading a little bit more and there's a couple of reasons for this number one you're using a larger antenna so the light uh or radio energy is coming from a larger area it's a little bit more diffused and it's wrapping around uh some of these different areas a little bit better but let's say we wanted to go a lot further I'm going to put this HF radio station on the other side of this hill you can still just barely see that it's there lighting up some of those branches and if the signal was strong enough we actually catch some reflection maybe from these rocks but let's pretend CU I didn't actually go to the trouble of modeling it ahead of time that we actually have a proper envis antenna we've swapped this out from an omnidirectional antenna to one that is going to point our signal in a very specific Direction specifically up okay so now something interesting has happened you can still see the edges of our original transmission over here but we're getting getting some red HF signal across the entire map it's not super strong but it's easily detectable if we look around the map we can see pretty good signal strength we cannot see the radio that is transmitting we only know it's there because of the Bloom on the trees uh but we're getting good HF signal on the entire landscape to figure out where it's coming from we have to look up uh past the black Sun of the Haron and hom World Getty Prime to this spot this is where our HF signal is coming from it's not bouncing off of an object but it's bouncing off of the atmosphere specifically the ionosphere by pointing the signal straight up it is bouncing off the ionosphere and coming straight down covering a pretty large area large enough that almost everywhere on the map is able to detect that signal so depending on what your use case is whether you're trying to get specifically down an alley and you'd rather other people don't hear or whether you're trying to cover an entire County or talk to people in the other counties Beyond you need to understand a little bit about some of these different frequencies some of the different antenna types and then some of the different Power considerations so let's recap obviously HF is weird and has some strange quirks to it but generally speaking the longer the wave length the longer your signal can actually travel and technically it gets weirder than that we're talking about HF uh like this down to like 40 m uh 80 M but there's something called very low frequency which we use to communicate uh with submarines that are underwater uh but there's even something called EF extremely lowf frequency radio communications which can penetrate about 300 ft of seawater and so at one point the United States had EF radio stations for communicating with nuclear submarines but it's a really complicated process you need massive amounts of power instead of one to five Watts they were pushing two megawatts and instead of small antennas or slightly longer multi-meter antennas they had antennas reaching over 80 miles so yes you can you can accomplish some amazing things with that but the other thing that you need to take away is the longer that wavelength is the slower you move data across it rumor has it that those EF radio stations could only transmit one letter every 5 minutes the shorter your wavelength uh the less distance you're able to get but the more data you are able to transmit that's why your home Wi-Fi probably used to be 2.4 GHz and now it's 5 GHz and 5G goes all the way up to 50 GHz so that you you just have more bandwidth more data transfer more quickly but again that comes at a cost you are no longer able to go through any obstacles uh and you don't have super long distances so now you have kind of a rough idea of what the different bands are capable of doing and some of the things that will help you send your signal where you want it the antenna choice is going to be very important one but the antenna placement is also vital elevation will almost always do more than just pure Brute Force wattage out of your radio and as long as you have an efficient antenna you're not wasting power uh being able to direct that energy to the place that it needs to go is going to give you the best banging for your buck but again you work backwards from the problem that you are trying to [Music] solve I hope you found this uh visual representation of RF signal propagation interesting actually no I hope you found it useful a lot of the T-Rex Labs videos that I've made so far are things that are already out there they're already pretty well understood they're things that I have studied for a long time but these are the things that I wish I could have seen when I first began to research them so that I could have a better picture of it in my mind and hopefully that's something that is useful to you and it's fun to Dust Light Wave off and mess around with it is technically a surprisingly robust Ray tracing engine for something that is now almost 10 years old and if we wanted to get super fancy we could get a modern multi-spectral renderer which has GPU acceleration and actually does the materials a little more physically accurately but I think this helps T-Rex has a long history of using LightWave 3D for things that it wasn't originally meant for so yeah we're just keeping up that tradition

Channel: TREX LABS

Views: 21,360

Keywords: radio signals, rf propagation, signal attenuation, radio range, rf signal, radiosity, viewshed, radio transmission planning, ELF radio, UHF signal, VHF radios, RF attenuation, Ham Radio, GMRS, Communication plan, PACE plan, terrain masking, Signal boosting, 3D simulation, directional antennas, emergency communication, emcomm, NVIS

Id: rL4Ebh23Xgo

Length: 23min 8sec (1388 seconds)

Published: Fri Mar 22 2024