Understanding technology is not easy. That's why Technology Master Kam is here to help. As a technology blogger, my aim is to make complex concepts accessible to beginners through RU-vid videos and social media interactions. I cover a wide range of topics including Ham Radio, SDR, Meshtastic, LoRa, digital communication, antenna designs, DIY projects and more. My passion for technology and desire to help others learn is what sets me apart. Join me on this journey and let's explore the world of technology together!
Range of communication is complicated. So make it simple we use line of sight communication. Antenna, coaxial cable/feeder and RF power also have their role. I have done a test on line of sight between two nodes using 22dbm on each side. 15 meter LMR400 cable with 3dbi vertical on one side and builtin antenna on the other side. I got reliable communication around 7 to 9 Km. Done another test with AB-89 transmitting 1.3watts in urban area, range increased to 2 km to 3km which was about 100meters without PA using its own 22dbm.
@@thierryf4ewi69 I just checked in DE. I am sure it is available elsewhere as well. If still cannot get it, please post here. (disclaimer, I am not affiliate of any seller) www.amazon.de/-/en/Amplifier-5M-6GHz-Broadband-Signal-Module/dp/B08CRFNKY9/
Thanks for appreciation, it helps keep me making more videos. Radio, scanner or receivers are the same for analogue as well as encrypted signals. We need to be sure that 1-our receiver/scanner is able to receive frequency of interest. 2-should have ample bandwidth to receive whole signal e.g an am radio with 500khz (don't remember exact) will not be able to receive FM radio signal as FM broadcast has 10MHz or more bandwidth. 3-receiver should have the capability to receive modulation type of the signal. Some modulation types are AM, FM, SSB etc. Some of the hardware that can be used for most signals include RTL-SDR, Hackrf-one, AirSpy R2 etc. Here is a list en.wikipedia.org/wiki/List_of_software-defined_radios
@TEKENGLOBAL Here is the video shedding some light on Meshtastic RF Birectional amplifier and its interconnections. I hope it helps. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Z3bmlwLmAjI.html
No, It does not. We need to reduce power of PA or SX1280 will be overdriven and burn out. What is the point to having PA? I am still looking for a good answer. You can find more info on this here www.lilygo.cc/products/t3s3-v1-0 An excerpt is given below. "⚠Cautions⚠ When using the "SX1280 2.4G With PA [H658]", it is recommended that the software control 1280 chip output 2 to 5 dbm, so that the entire module will output 20 dbm of power....................."
It is tricky. I PUT IT BETWEEN RADIO AND AMPLIFIER. Radio is usually the main source of harmonics and amplifier has no or very little contribution to harmonics. I will put filter between ANT and amplifier if there is too much interference in the area and my priority is to increase receiver sensitivity (remember this is a bidirectional amplifier i.e amplifier for TX and LNA for RX side). There is a 3rd scenario where I cannot ignore harmonics and I need best selectivity for LNA. I would go for two filters i.e one for TX between radio and amplifier and other for RX between Ant and amplifier(LNA)
Price mainly depends upon from where you are buying. Heltec Mesh Node T114 around USD 33 with NRF (not esp32) GPS is a good choice. See my this video for specs ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-5geXnH-ct2A.html on a little less around USD26 Heltec ESP32 LoRa Meshtastic Asset Tracker also called wireless tracker. If you dont need GPS you can go cheaper than $20. ESP32 consumes much more power as compared to NRF based chips. So ESP32 based boards should be low priced. I have checked prices from China. From Amazon UK they are +5. Apologies for the late reply. I am just coming back from unenforceable long break.
i accidentally dissabled the serial on my node while the node has BLE and Wifi dissabled. what is the command to turn Ble back ON thru the CLI? or even turn serial back ON?
Enable/Disable Bluetooth Module meshtastic --set bluetooth.enabled true meshtastic --set bluetooth.enabled false If nothing else works, take the some notes and reset the device. It will give you opportunity to reconfigure it. Apologies for the late reply. I am just coming back from an unenforceable long break.
@@technologymasterkam nothing worked, i coudnt talk to it thru USB serial. in the end after a couple of hours trying everything i somehow managed to start the flashing process by plugging it in and pressing buttons randomly. i think if you restart it at just the right moment as the computer try to flash, it suceed.
You can solder and USB connector on board for easy attaching to any charger etc. If you cannot find this connector for soldering on board, you can go ahead with cut and direct solder. You need to keep in mind that your charger should be able to provide 2 ampere or more current. May be you can try this search on Amazon www.amazon.co.uk/s?k=usb+connector+for+soldering Apologies for the late reply. I am just coming back from an unenforceable long break.
I don't find it in specifications. Keeping in mind the construction of a SAW filter, I can estimate(take it as my guess), it power handle capacity is more than 50watts RF. Apologies for the late reply. I am just coming back from an unenforceable long break.
Yes, of course. It works on 2.4Ghz frequency so it sees the signal coming from SX1280 and knows nothing about what we are using behind SX1280 i.e ESP32 or NRF based microcontroller. Apologies for the late reply. I am just coming back from an unenforceable long break.
Také jsem udělal video o SAW filtru pro LoRa Meshtastic. Používám SMD filtry velké 3x3mm a pájím je přímo na desku Heltec V3.1 do RX cesty. To má tu výhodu, že útlum 3dB se neprojeví v Tx cestě, ale jen pro Rx.
To je super!! Proč mi neposlat odkaz na vaše video, abych se s nimi mohl podělit se svými diváky. Omlouvám se za pozdní odpověď. Právě se vracím z nevymahatelné dlouhé přestávky.
I used the jpole calculators given in the description of the video. I added a few millimetres for hit and trial cutting. It is kind of too late reply. If you still need help, let me know. Apologies for the late reply. I am just coming back from an unenforceable long break.
Thanks. You can also add a BME680 Sensor pack to meshtastic for air quality telemetry. As well as tVOC gas resistance (air quality), it also includes temperature, humidity, and barometric pressure data.
@@technologymasterkam Did you see on the Meshtastic website that there is a group of paragliders in India who are using Meshtastic for communications and safety for Pilots who fly in the Dhauladhar Range. 😊 There is a link to their website and telegram chat group in the local community page of Meshtastic.
I am not in favour of using Meshtastic for safety, SOS and emergency mobile use. In my opinion, Meshtastic is not that reliable. For safety and 911 purposes, in a limited budget, get satellite communicator (Garmin etc) or at least a VHF HT (with good repeater coverage).
@@technologymasterkam I completely agree. . . For off grid casual communications I'd have to say it is very practical. The mesh in our city is really taking off. There are more than 100 active nodes.
For Signal Identification we are using eyes (FFT and Waterfall display) and ears (AM audio in this video). Here I explained ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Tv27mm7jmR0.html that we are using AM to listen to the signal and will use ADSB demodulator for actual decoding of signal. I hope it clears your concern.
Yes, 2.4GHz is old WiFi. I have a few videos on 2.4GHz Meshtastic band. Please let me know what you want to know and I will try to dig further into it. Thanks
@@technologymasterkam Well, a few things immediately come to mind. #1. The official Meshtastic frequencies are 433MHz / 868MHz / 915MHz. 2.4Ghz isn't an official Meshtastic frequency. The only item I can find on Meshtastic is if you actually use LoRA24 which is 2400.125, which is an extremely specific frequency. #2. Being that 2.4G WiFi is still heavily used worldwide, wouln't running a Meshtastic node on a WiFi frequency cause interference for both? (Unless I suppose using the precice LoRA24 frequency above?) Thanks. :)
Here is reply to your questions and assumptions. -Information posted about Official Meshtastic Fequencies is incorrect. Please check/recheck the source of information. -This is also incorrect. "The only item I can find on Meshtastic is if you actually use LoRA24 which is 2400.125, which is an extremely specific frequency." LoRa 2.4GHz band has 334 slots with a total bandwidth of more than 483MHz. This is the largest bandwidth available to Meshtastic in any band. -2.4GHz is not a WIFI band but an ISM band. WiFi uses this band with same privileges and priority as LoRa, Mestastic or DJI (proprietary protocol for VTX and control) is using it along with many others. How different services use the same frequency is a networking lesson for another time. However its basis comes from Ethernet Carrier Sense Multiple Access (CSMA). Present is far away from CSMA. en.wikipedia.org/wiki/ISM_radio_band Meshtastic uses LoRa protocol for its transceiver needs. Meshtastic/Lora 2.4Ghz band is an International band for Worldwide use. Its region setting is LORA_24. You can use it without license in any law abiding country. Here is the list of Meshtastic regions meshtastic.org/docs/getting-started/initial-config/ meshtastic.org/docs/overview/radio-settings/#frequency-slot-calculator If you still have any doubts or ideas, you are welcome to ask.
Nice video. Would the reults perhaps e more accurate if the antennas were vertical and in free space ? I found that many antennas are easily detuned by laying them down on a surface. Also it would be useful to see a table of your results to se how the antennas compare to each other. Keep up the good work !
Please see inline. -Nice video. 😌 -Would the results perhaps e more accurate if the antennas were vertical and in free space ? I think there is no concept of accurate results without high accuracy test equipment. This video was not using any of those. Polarisation of antenna does matter. It has to be same on receiver as on transmitter. It does not matter if it is vertical, horizontal, LHCP or RHCP. For Free Space, here is my reply ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-5KqB_qgxAaE.html - I found that many antennas are easily detuned by laying them down on a surface. It is not always true. It depends upon the type of surface and the surrounding objects. Anything that can interfere with Magnetism will change the properties of the antenna. Even things can interfere with magnetism will have varying degree of effect e.g fibreglass has very little effect than copper. The table I was using had little effect for the purpose of this experiment. The lab where we test antennas for educational or commercial purpose is a different world. I do not have video of it handy. -table of your results. It is a good suggestion but as we can see video is already around 8 minutes. I just added something very important in the end but stats show that very few people have time and patience to find it out :) No player likes to play a difficult match without supportive audience. Luckily I am getting more and more interested people like yourself. This makes me devote more time and effort. Thanks.
Necesita un filtro de 433 MHz entre la antena y el amplificador. Sería genial si pudieras conseguir un filtro SAW. Si tiene una estación de radio FM cerca de usted. Tienes que ver este ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-oDjI-1BmMNE.html Gracias por preguntar.
I have done my research before the video. I have already added some explanation (see comments below) and a link to Meshtastic website regarding 2.4Ghz International band. This is also available for US in addition to 915Mhz band.
Hello. Heltec wireless tracker boards have a hardware selection of the operating frequency range. The jumper is located between the Lora and GNSS antenna sockets.
@@technologymasterkam The source of my information is an inspection and comparison of two Heltec wireless tracker boards. One for the frequency range 433-510 MHz, the second 863-928 MHz. The first has a jumper on the contacts designated "RLF", the second jumper closes the "RHF" contacts. I would also like to note that the printed circuit connecting the SX1262 chip and the antenna connector has a choke and two capacitors of unknown value. It is quite possible that the choke is an antenna extension coil. In this case, the matching of antennas of 433 and 868 bands will not be interchangeable. In addition to all of the above, I noticed that the antennas included in the kits are poorly matched to European bands. For example, changing the frequency from 868 to 915 MHz gave a significant increase in signal level, signal-to-noise ratio and communication range. The antenna of the 433-510 kit is tuned to a frequency of approximately 480 MHz.
@@technologymasterkamAn inspection of both Heltec wireless tracker boards 433-510 MHz and 863-928 MHz showed that the first one has a jumper on the “RLF” contacts, the jumper on the second board closes the “RHF” contacts.
@@isthereafeeforthis 902.125 is confirmed. You can have a different frequency due to any other configuration change. If you need further help, please share you configuration for LORA. You can see screenshot on my website for frequency calculator by Meshtastic. technologymasterka.wixsite.com/technology-masterkam/post/how-to-switch-meshtastic-915-mhz-868-mhz-and-433-mhz-bands-on-sx1262-devices-technology-master
That looks really useful. Thank you for bringing it to our attention. Again, please provide a link to wher it can be obtained. Where are you located ? Is there more 433 or 868 activity where you are ? I have not yet tried it on 433.
Thank you, so nice of you. Here is url for RF amplifier www.aliexpress.com/item/1005006699272675.html Meshtastic is not happy with 433 due to duty cycle and EIRP limitations. However on 433 I have tried 2m and 70cm dual band antennas. They are economical, easily available more durable. Their performance is also great.
It is available on aliexpress. Available from many vendors. www.aliexpress.com/item/1005005445930926.html Option is Color: 868M Filter 2in1 B. I have seen people complaining and saying that they threw it away. In my view there are two most common reasons for problems with RF amplifiers. 1- Unstable and starving power supply. It has to be able to provide sufficient current with stable voltage when we are transmitting. 2- Is the overdrive. We should start at a lower dbm and keep increasing while keeping an eye on its performance. I know you are a master of Meshtastic, still adding my 2 cents. :)
@@technologymasterkam Have you done any tests for the overdrive? it seems that the default TX gain is 0. Have you tried to increase it? What's the default TX gain that it comes with? What was the TX gain that worked best for you? And thanks for all the informative videos you create.
I have not tried overdrive as it is not recommended by Semtech and others too. I usually keep drive a bit below the upper limit given in the specs. It produces unwanted noise and signals due to unstable or over voltage. When using an amplifier, we can start with minimal drive and then increase it keeping an eye on the received signal. - I am not aware of any default value. I have seen different value from different manufacturers. Mostly it is 22dbm. If we increase this TX value in the software, actual transmission still stays at MAX e.g 22dbm. - I usually use 22dbm while using node without amplifier. In my videos I have shown what value I am using for a specific test or experiment. If I have missed it somewhere or if you have a question about a video, do ask :)
@@technologymasterkam I was asking if you've tried the different TX levels on the amplifier. From what i see, the amplifier in your video comes with a default tx gain of 0.
Meshtastic uses LoRa protocol for its transceiver needs. It is not limited to 940MHz. Meshtastic/Lora 2.4Ghz band is an International band for Worldwide use. Its region setting is LORA_24. You can use it without license in any law abiding country. Here is the list of Meshtastic regions meshtastic.org/docs/getting-started/initial-config/ If you still have any doubts or ideas, you are welcome to ask/share.
@@technologymasterkam Oh WoW! I had no idea, I thought it was just the tri bands ..... so there's people/nodes out there all meshed on 2.4ghz band? With this amplifier you have here on the 2.4ghz , roughly how far transmission would you think to get compared to say the common 915mhz ~22db devices here in the states?
It may not win in the long distance due to many factors causing more attenuation to 2.4GHz than 915MHZ. I have outlined a few of these factors in a previous video. I have just published a video in response to your comment as it may help others asking about 2.4GHz. Here is the video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-cEPmm2q0HxA.htmlfeature=shared
ha ha ha. Yes that is true. I just don't want to miss anything that comes to my mind too related to the topic. May be I should drop more info. If you are missing something, please use CC. I could help in understanding what I am talking about. Thank & welcome to my channel :)
This is the main video. Tools used are explained here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ke2e0uyvDZ4.html If need any more info about the video, feel free to ask.
Great video. How did you get the board to transmit continuously ? Normally the pulses are very short. Does your power meter have a peak hold function ? SUBSCRIBED !
Power meter does not have the peak hold function. Taking reading of short pulses of LONG_FAST preset is really challenging. So I have changed preset to LONG_MODERATE which transmits for longer time as I explained here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ke2e0uyvDZ4.html also details of presets and transmissions are here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ytr4yWl77NA.html. Board is not transmitting continuously but I send text message to take reading. I have not setup a node to respond to these messages, so it transmits again and again for 3 times giving me enough opportunity to record video. I show screenshot from recorded video to make it more easy for viewer to read. Thanks for Sub and posting your question. If you get any other question related to videos, do ask :)
to do the bottom corners of the stub neatly without all that ugly crinkly bunching you get trying to "bend it" around the corner..... go flat/straight to the corner (say upper radiating element running left).. put a 45 degree bend on the flat to send the tape THE WRONG WAY flat with the sticky side upwards (ie going UP the page) but then immediately fold it back on itself to go down with the sticky side down for the bottom of the stub... then 45degree fold on flat to send the foil LEFT with the sticky upwards but then immediately fold back to run right with the sticky down to run the lower leg of the stub.... perfectly neat flat conductive corners with no bunching.
Thanks for sharing your thoughts. Short Answer: I just did what I planned to do. Long Answer: "Why are you doing it. Why don't you buy it. Look at your hands ..." I hear these things at times from people who in a way trying to help or guide me. If you look at my website, my tag line is "TECHNOLOGY FOR NON-ENGINEERS". If you check descriptions and tags etc you will find word "HAM" or "Amateur" frequently. I am not doing these videos to help professionals become more professional. RU-vid and Internet is already full of resources for that. I want to help anybody who wants to do it, just do it. What matters to me (fulfils my goal) is that it works. These antennas are not for sale. They are made with heart and love for oneself or friends.
@technologymasterkam Apologies; I am having to reply this way, for some reason my "reply" button doesn't work in the comments. Thank you for finding the video on the matching circuits. I will be examining the various boards in greater detail, and read the values of the matching components for the three 915 MHz devices I have so far. A few months ago I also mistakenly purchased a Heltec LoRa V3 tuned for the 433 MHz band instead of 933 MHz, and wondered if I could simply reprogram the SOC to 915 MHz, but I got warnings from advanced RF people to look carefully at the antenna matching network before doing so. They said this is because even though the SX1262 supports multiband antenna matching, the circuitry must be onboard to allow it to select the correct network, so when the manufacturer offers their boards in discrete bands rather than a "universally tunable" device, is it important to select the correct one for best performance. Another feature you could educate us about is the importance of using very short antenna leads, and selecting a quality antenna since those purchased from Amazon and the Chinese sites are often way out of tune. I found it to be very easy to build a 1/4 wave 915 MHz ground plane antenna with pretty good VSWR.
Thanks for the nice comment. Yes, I agree with 1/4 wave. It is easy to build, has great performance. It radiation pattern reaches all around. I have experienced incorrect antenna in this video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PZgHF0R1vkw.html and its followup here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BUB-kq8LP2I.html. I have just explained to another respected visitor the purpose of this youtube channel. I am very sure I cannot mislead professionals & engineers by my videos. They are fully secure :) Strip Quote " If you look at my website, my tag line is "TECHNOLOGY FOR NON-ENGINEERS". If you check descriptions and tags etc you will find word "HAM" or "Amateur" frequently. I am not doing these videos to help professionals become more professional. RU-vid and Internet is already full of resources for that. I want to help anybody who wants to do it, just do it. What matters to me (fulfils my goal) is that it works. These antennas are not for sale. They are made with heart and love for oneself or friends."
Interesting video, I was suprised using two apps simultaneously with different setting. But one thing I am missing here: The modules with SX1262 typically have 2 different LCR component placements, one setup for LF (433MHz) and another for HF (868+915MHz). I guess there will be some losses, if using a frequency which was not intended by the actual component placement.
It is very interesting to find out if there are losses, YES must be. I have just posted a video which I hope you will enjoy. It will provide you with more info. Thanks & welcome for sharing your thoughts. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ke2e0uyvDZ4.html
It's the antenna matching network that bothers me on some of these boards. The manufacturer's block diagram does account for an automatic antenna matching network, but the matching circuitry is external to the SOC, so are these devices equally equipped? The Heltec LoRa V3 is sold to operate on specific frequencies, and although the Meshtastic and other LoRa software allows band selection, the Heltec devices appear to use a simple matching network tuned for a specific frequency. It would be nice to know which boards have active multiband antenna matching.
This channel provides help to people who like to do experiments with radio, SDR, digital communication etc as a hobby. This is not targeted towards research and academic audience. Having said that, I appreciate your comment. Here is schematic of the device provided by Heltec resource.heltec.cn/download/WiFi_LoRa_32_V3/HTIT-WB32LA(F)_V3.1_Schematic_Diagram.pdf. In the LoRa section we can see the matching circuit which consists of c46, L7 and c47. Anyone can help the community by providing information about what values Heltec is using for different bands given in Meshtastic. Meanwhile I see no problem in switching between 868MHz and 915MHz. However there is some loss of power to/from 433MHz due to VSWR/mismatch which is still ok for experiments at low power.
@mbunds I tried further to address your question/comment and here is the video that can provide some more info into the subject. Thanks for sharing your thoughts ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Ke2e0uyvDZ4.html
RTL-SDR USB dongle. Rubber duck antenna as Meshtastic test node was nearby. SDR Software is SDR Sharp latest version with all plugins. Full video is here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ytr4yWl77NA.htmlfeature=shared
You can use UART (4 wires) or 2 wire protocol like I2c for hardware integration between Heltec Wiresless tracker and Sensors, Mortors etc. If you want to add Arduino between the sensors and tracker, you can also do that by using/soldering headers provided with tracker. On the software side Meshtastic Serial Module can help providing simple communication interface.
You can use I2C or any other 1 wire protocol. May be we can use GPIO but we need to see ultrasonic sensor and servo motor has support for which protocol that is available on Meshtastic node.
the USB-C port provides 5V, the board runs at 3.2v, so there is power loss stepping it down cause it is used to charge a battery. To get true readings you must measure the power draw from a battery instead of the USB-C port since it is meant to be used that way. On repeater mode at power save mode i've gotten readings as low as 13mA on idle and 105mA when sending messages.
I want to thank you for sharing your thoughts. There is more than one to reach a conclusion. Which way I chose or someone else chose depends upon how accurate results we need and willingness to spend time and money on it. The tests I have performed are not research level tests going as basis for scientific thesis. They are go people doing it as a hobby. So charging reading was taken with charging on - charging off while keeping all other things almost the same. 2) As you have mentioned that you were using power save mode, these reading will not match reading shown in the video as I was not using power save but trying to emulate normal use. 3) I am really happy that you are experimenting with these devices and sharing the results. Meshtastic Discord group is very active community where you can ask/share your results in addition to comments here.
