Shortwave data transfer for land based rover

Thread Starter

jgreene44

Joined Dec 8, 2016
108
at this point i plan to transfer the data much like the very first dial up modems. computer generates tones that the receiver interpenetrates into usable I/O. if someone here with more wisdom then myself can see what im doing wrong before i do it or, knows a better way. id love to hear from you. thanks in advance.
 

Papabravo

Joined Feb 24, 2006
18,138
at this point i plan to transfer the data much like the very first dial up modems. computer generates tones that the receiver interpenetrates into usable I/O. if someone here with more wisdom then myself can see what im doing wrong before i do it or, knows a better way. id love to hear from you. thanks in advance.
Do you have any objection to using an existing method such as RTTY, PSK-31, Olivia, or JT-65?

https://en.wikipedia.org/wiki/Radioteletype
https://en.wikipedia.org/wiki/PSK31
https://en.wikipedia.org/wiki/WSJT_(Amateur_radio_software)
https://en.wikipedia.org/wiki/Olivia_MFSK
 

DickCappels

Joined Aug 21, 2008
8,685
at this point i plan to transfer the data much like the very first dial up modems. computer generates tones that the receiver interpenetrates into usable I/O. if someone here with more wisdom then myself can see what im doing wrong before i do it or, knows a better way. id love to hear from you. thanks in advance.
What is it that you are doing for which you seek an opinion?
 

Thread Starter

jgreene44

Joined Dec 8, 2016
108
papabravo! no i do not have any objection to using existing gear in fact that's what i'm hoping to do. i just know very little about shortwave. just the basics what it is how it stays in the atmosphere. would you mind to go one farther and tell me what gear you would use to do this? id like the rover to be able to communicate with a IOT website and also send back low res photo's so i can see where its at and where i need to tell it to go next. i did look at some psk31 transievers but i dont really know what im looking at as for as to compare or how it will perform.

mr cappels. im building a land based rover and communicating with it via shortwave. thats the intention anyway. data speeds will not be a huge issue as the unit will be able to lay dormant and await the next command.
 

Papabravo

Joined Feb 24, 2006
18,138
papabravo! no i do not have any objection to using existing gear in fact that's what i'm hoping to do. i just know very little about shortwave. just the basics what it is how it stays in the atmosphere. would you mind to go one farther and tell me what gear you would use to do this? id like the rover to be able to communicate with a IOT website and also send back low res photo's so i can see where its at and where i need to tell it to go next. i did look at some psk31 transievers but i dont really know what im looking at as for as to compare or how it will perform.

mr cappels. im building a land based rover and communicating with it via shortwave. thats the intention anyway. data speeds will not be a huge issue as the unit will be able to lay dormant and await the next command.
Without more details it is impossible to offer advice. Will you be using "shortwave" frequencies that require you to have a license or were you thinking of using unlicensed spectrum? Will you be using commercially produced equipment or will you roll you own? I'm not sure what range and reliability requirements you have, but you need to start being way more specific.
 

Thread Starter

jgreene44

Joined Dec 8, 2016
108
papabravo. ok im sorry. i did not mean to be vague. currently im not limited by any certain frequency range. in fact this at the moment is for testing purposes only. so to over simplify it... in whatever way you think that would be the best to communicate with this rover. the only limitations would be setup and cost. as long as the setup can be accomplished in a reasonable amount of time by myself and is within a reasonable budget i'm all ears! recently i began i project where i convert 2.4 gig wifi into a proprietary signal generated at 63MHz. the lower attenuation of that freq was the main reason. many envision long range wifi. this has the ability to cross state lines! and no we dont use it! its not legal was for testing only. but nowww.... i want to start on this. being within what would be considered ham radio would be a bonus. i could actually use the thing. but defiantly interested in any solution you provide!

after reading your post again... (papabravo). you said the unlicensed band. that evaded me initially. is there a shortwave band that does not req. a license? if so yes that would be nice as well. however if i have to limit my data xfer because im only able to operate in that band. i would have no problem going and getting a proper licence. from the reading i have done, based on your initial suggestions. seems that around 31 baud is a decent rate. i do want to get a better understanding of what kind of speeds i should expect and via what method would give the best performance!
 
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Papabravo

Joined Feb 24, 2006
18,138
papabravo. ok im sorry. i did not mean to be vague. currently im not limited by any certain frequency range. in fact this at the moment is for testing purposes only. so to over simplify it... in whatever way you think that would be the best to communicate with this rover. the only limitations would be setup and cost. as long as the setup can be accomplished in a reasonable amount of time by myself and is within a reasonable budget i'm all ears! recently i began i project where i convert 2.4 gig wifi into a proprietary signal generated at 63MHz. the lower attenuation of that freq was the main reason. many envision long range wifi. this has the ability to cross state lines! and no we dont use it! its not legal was for testing only. but nowww.... i want to start on this. being within what would be considered ham radio would be a bonus. i could actually use the thing. but defiantly interested in any solution you provide!

after reading your post again... (papabravo). you said the unlicensed band. that evaded me initially. is there a shortwave band that does not req. a license? if so yes that would be nice as well. however if i have to limit my data xfer because im only able to operate in that band. i would have no problem going and getting a proper licence. from the reading i have done, based on your initial suggestions. seems that around 31 baud is a decent rate. i do want to get a better understanding of what kind of speeds i should expect and via what method would give the best performance!
If you have an amateur radio license, doing the development and testing will be easier. The unlicensed bands are called ISM bands. Here is the wiki on these bands.

https://en.wikipedia.org/wiki/ISM_band

We need to home in on your understanding of "shortwave". My definition of shortwave covers the frequency spectrum from the top of the AM broadcast band (1.6 MHz) to the bottom of the VHF band where the old analog TV channel 2 resided (54 MHz.) Even at low power signals can propagate very long distances, as in thousands of miles. I'm pretty sure you're not interested in that since the reliability of long distance propagation is low now that we are headed for a sunspot minimum. As you go up in frequency this effect is reduced. As we move into the VHF spectrum the effect is less and less. I recommend using a VHF frequency that will give you several miles of coverage but not reach people in the next county. My experience using data transmission is with typing messages on a keyboard and exchanging those messages over an RF link. I usually don't require error free data transmission since critical information can be repeated. I suspect this will not be true in your case. I would start by identifying some RF modules that you can doe data transfer experiments with. Since it will take you sime time to get the amateur radio license you require I would start with some modules for one of the unlicensed ISM bands. You want this module to have a data input from a computer so you can try various pieces of software to send and receive data.
 

Thread Starter

jgreene44

Joined Dec 8, 2016
108
ok my understanding of shortwave is not much better then knowing its a very low freq. and no i did not know it went so high. i consider that i great thing. i defiantly need your understanding of these lower freq.'s 54MHz is a good start for me that begins the range i worked on for a portion of my career. im an aerial linesman. my title at the time was system tech. hope that doesn't sound boastful just want you to have an idea of where my understanding is. fairly complex understanding from 54MHz to about 1 gig. 2.4 perfect understanding of the basics. been getting into some really advanced stuff. shortwave. i had a 1950's tube radio that im pretty sure no one thought worked when i found it. gosh it was kewl! but that's about it. oh wow! i did just learn something from you. i was about to ask if i could broadcast just under 54MHz and that didn't seem right so i took a quick peek at the united states frequency allocation chart. there it is! right under 54. i wonder what kind of gear is available at that freq. all the same as any shortwave transmitter? i'm thinking not. halp! lol cant wait to hear from ya!

few other words i just wanna toss in there... arduino. IOT navigation. control the movements via rf? alot to consider. i mean maybe im just dreaming thats what im trying to determin. pisk31 was it? sends simple data back and forth. its the only setup i can think of that currently exists and could be compatible with the IOT website
 
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Thread Starter

jgreene44

Joined Dec 8, 2016
108
then im not even sure i really need web access or IOT. normal toy rf receiver. low freq. crystal. shortwave low. could i then navigate with just rf.... how would i get photo's back i can easily get the arduino to take a pix and transmit it. via rf with one servo move. not real sure about transmitting that low or receiving. im guessing you can... i think the transmitting and receiving of a photo is where im really lost. getting the data to move stop wait turn. that part seems more clear. lastly i can get a few miles on my current setup but honestly if i can only go a few miles its not much better then my long range 2.4. most of what i would want to see around the area in which i live is happening right here anyway. now if i could send it off on a journey that has no limitations. that would be worth sharing with others!

i have to add this too. i have heard about concerns of reliability. like it would be a deal killer. i think not however. this rover will be able to be dormant for long periods. actually gaining voltage via solar as it waits for its next command. that part i think i'm ok on. and if you include a setup that may go in and out. ya thats fine. i just want to try what you think is best. you got a lot more wisdom in this then myself.
 
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Thread Starter

jgreene44

Joined Dec 8, 2016
108
i would have wrote this all in one message. not letting me edit after 10 minutes and i keep having after thoughts. i keep thinking about coming in just under 54. however. will that high of a freq. stay in the atmosphere like the shortwave radio i had long ago?

i have one of these:
http://www.ebay.com/itm/26265172962...49&var=561559741766&ssPageName=STRK:MEBIDX:IT

and a demod i/c. i could demodulate to baseband. output to 52MHz but im not sure if the signal will keep its integrity.
 
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DickCappels

Joined Aug 21, 2008
8,685
Based on an earlier comment, you appear to be in the United States. If that is the case, you will probably benefit reading the brochure from the FCC below. This forum cannot support illegal activity.

UNDERSTANDING THE FCC REGULATIONS
FOR LOW-POWER, NON-LICENSED TRANSMITTERS


Those ESP8266 modules should be able to do the trick and are probably "legal", but they are not easy to use. If you find a way to get one to do something interesting, please share it with me.

You might find the Nordic NRF2401 modules easier to work with. Scott Vitale includes direct support for it in AttoBasic (for AVR/Arduino).
http://www.ebay.com/itm/2pcs-NRF24L...sceiver-Module-For-Microcontrol-/251044600998
http://www.ebay.com/itm/2pcs-NRF24L...sceiver-Module-For-Microcontrol-/251044600998
 

Papabravo

Joined Feb 24, 2006
18,138
I don't think anybody was contemplating anything illegal. Specifically I mentioned the use of modules that do not require a license, using the ISM bands so you can experiment with higher than milliwatt power. While conducting these experiments I suggested getting an amateur radio license. It took me about 5 months to get my technician and general class licenses. That was in 2005 before they eliminated the Morse Code Requirement. If you want to use the spectrum just below 54 MHz, that is part of the amateur 6M band and I can tell you from experience there is very little activity there. One problem with that frequency is if your transmitter has a 2nd harmonic spur it will crash your neighbor's FM radio while he is listening to Mozart on a Sunday afternoon. Bad ju-ju!
 

Thread Starter

jgreene44

Joined Dec 8, 2016
108
@cappels. this post actually speaks of myself making sure to comply with the laws set by the fcc. furthermore states currently for testing purposes only. no offense but it does clearly speak of this. i do have both of those modules and i will let you know if i find anything usefull and outside their normal parameters. be glad too!

papabravo! hey thanks for the advice but none of that pertains to the many questions i have. can you or anyone look over my last post and give it a go? i would sure be greatfull. thanks in advance!
 

Papabravo

Joined Feb 24, 2006
18,138
@cappels. this post actually speaks of myself making sure to comply with the laws set by the fcc. furthermore states currently for testing purposes only. no offense but it does clearly speak of this. i do have both of those modules and i will let you know if i find anything usefull and outside their normal parameters. be glad too!

papabravo! hey thanks for the advice but none of that pertains to the many questions i have. can you or anyone look over my last post and give it a go? i would sure be greatfull. thanks in advance!
Let's take things one at a time. You last posts were #9, #10, and #11. I don't have any experience with the ESP8266 so I can't advise you on the uses of such a device.

You could have one of these devices in the vehicle and one at your base station. Your range would be line of sight and range maybe 50', using 2.4 GHz as the RF link.
 
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