Looking for long Range Wireless Audio transmitter and receiver - Page 1
Forum section: electronics / rf-microwave

author: jtronix
author_rank: Regular Contributor
timestamp: April 10, 2017, 03:54:53 pm
content: Hello,I'm looking for long distance about (5-10 km) audio voice transmitter and receiver.I'd seen few chip from TI and NXP Sub GHz but i'm unaware of that whether it is suitable for audio or notcan someone plz suggest any ready device and any chip for development

author: BravoV
author_rank: Super Contributor
timestamp: April 10, 2017, 03:56:14 pm
content: Quote from: jtronix on April 10, 2017, 03:54:53 pmWhats wrong with ordinary CB radio ?

author: jtronix
author_rank: Regular Contributor
timestamp: April 10, 2017, 04:21:30 pm
content: I would like to design my own device with microcontroller so that i can assign each devices to unique ID and it can only communicate to that particular device.

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: April 10, 2017, 04:51:40 pm
content: The problem is, that radio frequency bands are a scarce resource. For the range you want to achieve, you would need to stick to CB, using gear officially tested for compliance (with the ups and downs of sharing it with other users for free), or buy a dedicated frequency band (what is close to impossible for private persons and also pretty darn expensive).Especially for high power transmission there are a lot of regulations in terms of frequency bands you are allowed to use, what type of modulation, if you are allowed to use encryption and so forth - not to mention, your self-builds need to comply with your states laws.If range is the main concern, maybe stick to GSM and use the existing cellular network? (Also there is the ISM band, but I do not know a lot about that)Keep in mind, that you are not allowed to just build a device capable of transmitting on RF and pump out 1.21 Gigawatts, so your signal reaches its destination.DON'T DO IT.If you are lucky, it is just a whole lot of money you need to pay as a fine. But in case you somehow interrupted professional frequencies for air traffic, or emergency services (police, fire brigade, search & rescue,...) you are in deep shit.

author: eb4fbz
author_rank: Regular Contributor
timestamp: April 10, 2017, 07:46:26 pm
content: Simple: you can't(*) get that range with an unlicensed transmitter.(*) Physics says you actually can, but only in line of sight conditions, which includes fresnel elipsoid. With no interferences from other unlicensed transmitters sharing your band... So no, at least not in a repeatable manner or with a minimum reliability.

author: ebclr
author_rank: Super Contributor
timestamp: April 10, 2017, 08:32:29 pm
content: http://www.brickolore.com/2012/03/baofeng-uv-5r-schematics.htmlhttps://pt.aliexpress.com/item/HOT-2-Pcs-5W-128ch-Two-Way-Radio-Walkie-Talkie-Baofeng-Uv-5re-For-Hunting-Dual/32684470209.html?spm=2114.02010208.3.58.PjWyXk&ws_ab_test=searchweb0_0,searchweb201602_2_10152_10065_10151_10068_10136_10137_10060_10138_10062_10141_10056_10055_10054_10059_124_10099_10103_10102_10096_10148_10147_10052_10053_10142_10107_10050_10143_10051_10084_10083_10080_10082_10081_10110_10111_10112_10113_10114_10037_10032_10078_10079_10077_10073_10070_10123_10124,searchweb201603_6,afswitch_1,ppcSwitch_5&btsid=c4b44659-bc50-4dde-b413-e7216b4c1497&algo_expid=43f3205c-c1b3-40b3-9b7d-e117af18e69a-6&algo_pvid=43f3205c-c1b3-40b3-9b7d-e117af18e69a

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: April 10, 2017, 08:44:10 pm
content: You will still need to have an amateur radio operators certificate to use these Baofengs for transmitting.For packet ham radio start here:Wikipedia on packet radio

author: jtronix
author_rank: Regular Contributor
timestamp: April 11, 2017, 07:54:23 am
content: Is there any possible way to keep communication private because in wakie takie voice can be listen by other device.I want to use micro controller for get input from Mic and send it to some different format so that data can be received by only device who can decode it correctly.Any Device from NXP,TI,ST,Microchip,...etc??Does WiFi work for this?Note that i'll be use this in open space (at mountain) so there will be no wall or any object will come into picture for communication.

author: Jeroen3
author_rank: Super Contributor
timestamp: April 11, 2017, 08:02:24 am
content: This is called the cell phone network. You could also use satellite network, but that might be out of budget. You can connect to this cell phone network for a small fee.

author: Pete67
author_rank: Newbie
timestamp: April 11, 2017, 12:34:36 pm
content: If you have line of sight then it should be possible to set up a point to point WiFi network link over that distance and use VoIP protocols to carry speech. With decent encryption this can be fairly private. It's more of an IT solution than you had in mind but it should work.

author: KD0CAC John
author_rank: Frequent Contributor
timestamp: April 11, 2017, 12:52:56 pm
content: Quote from: jtronix on April 10, 2017, 03:54:53 pm1st put your country's flag up , so you can get more specific info ?But I suspect that there is no place that allows unregulated RF transmission .Then you are basically talking about voice encryption , so falling into another regulated part , depending on country ?

author: Jeroen3
author_rank: Super Contributor
timestamp: April 11, 2017, 01:01:56 pm
content: Quote from: Pete67 on April 11, 2017, 12:34:36 pmYes, but you'll need those Ubiquiti AirMAX dish stuff for it to work.

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: April 11, 2017, 01:16:11 pm
content: Also, for line-of-sight situations:optical communication

author: LaserSteve
author_rank: Super Contributor
timestamp: April 11, 2017, 02:19:32 pm
content: Most countries, even the harshest dictatorships have some form of Land Mobile Radio dealers and a licensing scheme. Non line of sight communications in mountainous areas are usually High HF to Low VHF, 25 to 75 Mhz. They often involve a repeater opposite the mountain face, typically on another mountain. A license, either business band or amateur radio for non-profit events, is required. Unless this is some sort of strange hobby project, the original poster would be wise to use Cellular or contact a Professional.I can attest from years of doing this that line of sight is a "relative" thing. If you truly do not have a direct shot, or there is a forest, jungle, or dense foliage on the mountain, you end up needing a repeater, or specialized techniques like "Near Vertical Incident Skywave" or Packet Radio. Often your comms may have multipath or diffraction issues as well.Rarely will license free anything work well at your specified distance without large fixed antennas, or dishes/panel antennas in the case of microwave. 2.4 Ghz WIFI exists because that frequency is strongly adsorbed by anything organic, like trees and even water vapor in the air. Other then for Radar and point to point links, the 2.4 Ghz band is pretty much useless otherwise. Which is why WIFI is stuck there, the high adsorption makes it impractical to sell the frequency to cellular companies.This is not a "chipset" problem, this will require a moderate to high power radio, most likely a minimum of 5 or more watts at VHF, and most likely a type approved radio, certified by your local agency that handles RF regulation. Or a microwave system with a modest ERP if you have true line of sight.You will need really good antennas, and a good antenna usually means that you will be violating the allowable "Effective Radiated Power" for a license free service.Often the frequencies used are shared and coordinated, and while your nearest co-user may be 50 Kilometers away, you will not have "private or secure" in most cases. In my country, the simplest Business/Personal license for a coordinated frequency is 90 Dollars for five years plus a small fee to a private non-profit company that allocates the channels. That gets me five channels 6.25 KHz wide, of which I can use one at a time. There are five more channels paired with my channels five Megahertz up. These are the repeater outlet channels, if I need a repeater. I'm supposed to limit my activities to a 50 mile radius of the license point. I cant send data over a repeater with the present license.There are un-allocated "free" channels, but everybody and their brother/sister uses them, so I prefer sharing with 10 users across the region rather then anyone who can buy a radio at Amazon or Walmart.By the way, use my allocated frequency without an ID, and its a happy day on Sheldor while I ENJOY hunting you with a spectrum analyzer and various other techniques. Not much will happen when I find you, other then a simple request to cease and desist. If you don't, I document your signal with a screen shot and report it to the authorities. I'll give you an example:Last time such an event happened, I as a local ham, moderated the relations between a home owner and a local two way radio company. She was threatened with a 8,000$ a day fine, and could not understand that an oscillating TV antenna preamp was taking out a repeater input. She refused access to her home, and the radio company had already called the FCC. After all, she did not own any transmitters as far as she was concerned.She started calling around, including the local electronics store, trying to find a way to "Keep these strange men" out of her house. The broken preamp oscillated on the input of a digital repeater leased to Federal law enforcement. I just so happened to be at the parts store. I called her, then I called the company and explained her situation, they explained about tracing the signal to her attic. I called her back, , told her basically a warrant would not even be required, and urged the president of the company to reign in his overzealous technicians. I told him to buy her another pre-amp, pop up at the house door with it in a suit and with business card, and all would be over. That worked. Moral of the story, use a frequency where your allowed to be. The next day a Federal Marshal and the FCC Engineer would have been at her place, and neither would not have been a happy fellow.I'm also aware of a Swiss case where a Ham repeated a urgent distress call, saved a life, and lost his license and government job in the process. Listening to an un-authorized frequency with a scanner...In most nations, the license free frequencies are bordered by licensed allocations, and if you stray.. you do so at your own risk. If you do not know and check you can end up disrupting "Safety of Life" communications. Possession of the device after a complaint is pretty much an open and shut case.If you really need this, consult a professional, or get a amateur license for all involved if you are doing a non-commercial project. Most Nations now just have a "multiple choice" test to get the license and a modest fee.Steve

author: jtronix
author_rank: Regular Contributor
timestamp: April 11, 2017, 03:31:23 pm
content: please see DRA818U from dorji. It seems to be perfect for voice communication but not sure about range and interfacing with microcontroller

author: frozenfrogz
author_rank: Frequent Contributor
timestamp: April 11, 2017, 04:02:20 pm
content: Can’t figure if jtronix is trolling, or just ignorant.@jtronixLaserSteve and everyone else gave you all the information you will need. Go read, go figure.Don’t call on this frequency anymore. I’m out.

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 11, 2017, 04:41:16 pm
content: @jtronix would appear to have a history of asking questions and then arguing and not understanding the answers.His continued refusal to identify his location will limit responses to this question to very generic answers.

author: ebclr
author_rank: Super Contributor
timestamp: April 11, 2017, 08:36:25 pm
content: Raspberry pi and skype will do that

author: LaserSteve
author_rank: Super Contributor
timestamp: April 12, 2017, 04:01:21 pm
content: @jtronix,I'm rarely mean to fellow netizens, but in this case, I'm going to make an exception.Based on long experience, I and others told you what you need, and that you need specialized help for this task. I have a DRA818U on my bench, and you would find its the core of an Early Baofeng, thus unsuitable to your use. It tunes two of the most congested allocation bands in the world, and barely has enough power and receive sensitivity to hit a repeater, let alone go 10 KM without a YAGI or Log Periodic. Not to mention the need to certify it as a radio unless your a Ham, everywhere in the world. It also usually takes 30 days to ship.At least your not in charge of comms/data at the Ski Hill at the upcoming Olympics.Please QSY to reality.N8*** clear...Steve