#292 Wi-Fi Antennas with Gain and ESP32 Long-Range Mode (part2)

in the last episode we looked at some theory and learned that not all ESP 32 modules are good with external antennas as promised today we will continue the video and look at some antennas with gained glitzy youtubers here is the guy with a 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 I learned an easy way of comparing Wi-Fi antennas from Andrew McNeil you find a link to his channel in the description he uses a PC and software called wrist humbler it shows all access points around you on your pc screen to test antennas I go to our terrace on the top of the house connect a USB Wi-Fi module to my laptop and connect it to the antenna under test then I select a remote access point and write down its RSSI please keep in mind that minus 70 DB is more signal than minus 100 dB now I can change to another antenna and should get the relative performance of course only if nothing changes in between the access point and my antenna this is why I do it several times and sometimes with different access points you can also estimate the directionality of your antenna by watching the RSSI of a particular access point while turning your antenna really simple speaking of directional antennas of course we want to have one or better a few of them to compare I have here a home-made helical and two panel antennas purchased on eBay for ease of comparison I use known access points three of them are in the same building roughly 500 meters away let's start with an ordinary omnidirectional antenna as expected it does not detect the access points next is this panel antenna it should have 14 DB I gain now I see the access point not a stable connection but definitely better than with the omnidirectional antenna the next is my homemade helical antenna it is straightforward to build if you use these instructions and using this calculator you can make a helical for any frequency as proposed I used a PVC tube but in the do-it-yourself shop nearby and as you can see I confused diameter with radius and the first holes were wrong now I can use two of them to mount the antenna to a pole I think this is a good excuse for the helix I use a simple trick this copper band is made to connect small solar panels it is very flexible I fixed it on one side of the tube using captain tape the build took less than an hour including the wrongly drilled holes but unfortunately it had a very bad SWR after some investigations I found the solution a piece of copper with the length of lambda quarter attached here did the trick I use this copper band for several other things especially for shielding it is very flexible and has a sticky side the antenna also should have 15 DB I gain and if I compare it with a panel antenna it behaves similarly so longer is not always better sometimes thicker or broader is better or at least as good so we answered that vital question often asked by viewers we evaluated the antennas we can use for the long range test and I found a place which is visible from here and also can be reached by bicycle or car it is around 7 kilometers away suitable for a first try but wait what about legality the panel antenna should have a gain of 15 DB I let's say 12 if we subtract the over-promised of the seller and the cable loss 6 are allowed by the FCC all in all we are 60 B - hi fortunately the ESP 32 has a simple possibility to reduce the output power so we go with 13 DBM output power and we are okay for the transmitter the ESP on the receiving site does not emit if we use this sketch I checked it with the spectrum analyzer I can even take the second panel antenna with me to increase the gain of the whole link or if I only want to send sensor data in one direction I could use a only directional antenna for the transmitter and a directional antenna for the receiver anyway we will use these two sketches unfortunately I'm no more allowed to read the names of the sketches provided by this project according a viewer this would be politically incorrect but at least I made sure that the PCBs I use are green so it should be okay but before I leave to the range test in nature I would like to show you the effect of output power reduction on power consumption of the ESP 32 we all know that it consumes quite some power when the transmitter is on fortunately only for a short period I use my new child meter to measure the short current spikes and really the ESP draws up to 350 5 milliampere at 20 DBM output if we go down to minus 1 DBM you see that the output power really is lower and also the power draw but the difference in power consumption is only about 10 percent on average because the peaks are very short it might be different if you deep sleep your MCU between the transmissions then savings could be higher at least in percentage first I wanted to test expressives promise to bridge one kilometer in long range mode I mounted a standard ESP 32 development port on a short pole and took my bike to peddle towards the opposite side of the valley here you see our house the connection worked but only when I turned the receiving ESP in the right direction and as you see the RSSI is quite low for a productive use I would add some antennas to stabilize the connection but yes it worked now I mount 2 antennas on two poles and connect ESP 32 s to each of them one transmits in 11 B and the other in long-range mode and because it started to rain I took my car and drove to the point I found using the online service created by VA to tbe it showed an old castle where I should have a line of sight for my American friends yes we have ancient castles everywhere usually in nice places if you want to see another one maybe you watch my video on my attempt to establish the Laura world record the weather is awful and I'm not sure how much influence this humidity in the air has on 2.4 gigahertz signals so I start with the place 2.5 kilometres away I still have a reception in the long range mode using the directional pageant I did not check the normal mode because the RSSI values were already quite low the next location is 4.7 kilometers away to check if I have line of sight I brought my Laura tracker with me it connected to my home gateway without any problems unfortunately both Wi-Fi modes did not work anymore on my way back I stopped at a distance of 1.5 kilometers both modes worked with a directional patch antenna I had no reception with the PCB antennas an interesting detail the RSSI value of regular Wi-Fi is higher than with the long-range mode even if I use the same board an antenna the difference is here the long-range signal is transmitted by the patch antenna and the 11 B signal by my long helix maybe longer is really better I decided to investigate this mystery later perhaps even in a video because the reach of the long-range mode already stopped before 4.7 kilometers I had no need to visit the castle maybe next time maybe then the weather is better and maybe next time I add these 2.4 gigahertz Laura modules to the tests stay tuned summarized we used the basics of antennas to plan for the next steps we looked at the new long-range mode of the ESP 32 and how it can be switched on we attached external antennas to different ESP 32 modules and found some flaws and other tricks to improve the range for your devices we found and used an easy way to compare Wi-Fi antennas and used this knowledge to select the right antennas for the following tests I also showed you a self-made helical antenna it seems that it works quite well we understood that we have to reduce the TX power of the ESP 32 to stay legal and how to do it lowering the output power reduced the peak currents consumed by the ESPE 32 considerably the overall effect however was only 10 percent because I did not use deep sleep in this investigation the different test shows mixed results the long-range mode seems to be a little better than the normal mode but not to much we should not expect wonders because the transmitted bandwidth as well as the bandwidth of the receiver stays the same so I assume that this mode will be for niches where you cannot solve your problem with a directional antenna what experience do you have with this mode and with orts containing PCB antennas and antenna connectors maybe you leave a comment for the other viewers one last thing after returning to my lab I can show you my trick to ease the work on my remote project I always use such a box where I put everything I use for this project simple to carry and enough space for small and bigger parts like that I do not forget things and do not need to walk 10 times back and forth to my lab during a remote project I hope this video was useful or at least interesting for you if true please consider supporting the channel to secure its future existence you find the links in the description thank you bye you

Channel: Andreas Spiess

Views: 63,994

Keywords: esp32 external antenna, arduino, arduino project, beginners, diy, do-it-yourself, eevblog, electronics, esp32, esp32 datasheet, esp32 project, esp32 tutorial, esp32 weather station, esp8266, esp8266 datasheet, esp8266 project, greatscott, guide, hack, how to, iot, lorawan, nodemcu, smart home, ttgo, wemos, wifi, antenna, helix antenna, helical antenna, helical antenna wifi, tutorial, internet of things, esp32 arduino, esp32 arduino ide, esp, arduino ide, raspberry pi, internet of everything

Id: PUppoaePi3A

Length: 12min 0sec (720 seconds)

Published: Sun Oct 13 2019