hi i need help! i want to send data via a uhf voice tranciver(walkietolklie) with a low bitrate(i dont mind). so ineed some good ideas about that. i have a pair of uhf transceiver with a total bandwidth of 700khz and it is from 700khz to 1400khz. so i need to convert data to voice and then voice to data.plz help

 

You can convert data to voice by ripping out the microphone on the transmitter, and replacing it with an astable multivibrator running at a few dozen hertz. The multivibrator promotes the data. When the multivibrator is not functioning, a binary 0 is sent.

For voice to data, rip out the speaker in the receiver and replace it with the Stereo VU meter found at talkingelectronics.com.

For best results, make sure the reveiver recognizes the speed of the transmitter (multivibrator frequency), or you will lose characters.

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

 

thnx for that but my real problem is that i dont want to remove mic or speaker! i need to use it for sending data and voice and i dont want to recieve fake data if someone talks! So i need some kind of modulation or something! of course i dont want to send data and voice at the same time.

 

How can you send data with a speaker? are you going to runthe transmitter through a food procesor so that the receiver makes a continuous clicking sound? :lol: or are you going to consistently smash the transmitter until you hear something in the receiver? :lol:

In other words, speaker should not be used as data input because it isn't reliable. It is better for voice input.


Thats why I said rip out the microphone. The microphone is the thing someone talks into. The only other way your transmission is screwed is if a nearby transmitter is transmitting at the same frequency.

use the transceivers you already have. the speaker accepts input, and modulates it to a higher frequency.

then go with my above suggestion in my first reply.

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

 

man here is paint about! i know its hard! but plz give a try! i need those 2 boxes (audio2data mod & data2audio demmod)!!!!!!!!!!! thats what i need and if i get those 2 boxes i ll have both data and voice com!!! and i dont mind if i have a beeep on speaker when i send data! thnx a lot!!!

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It sounds like you are describing a modem - modulator/demodulator. Sometime between the time that dinosaurs ceased to roam the earth and the present time, computers were linked to each other via a telephone modem. You put the handset in the modem's cradle on each end and the modem converted the datastream into audio (modulate) and then at the other end it converted the audio into a datastream (demodulate).

With your transceivers you'd be limited to one way communication however you could use two pairs for two way communication.

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stevez

 

stevez:
It sounds like you are describing a modem - modulator/demodulator

me:
thnx for info


stevez:
Sometime between the time that dinosaurs ceased to roam the earth and the present time, computers were linked to each other via a telephone modem. You put the handset in the modem's cradle on each end and the modem converted the datastream into audio (modulate) and then at the other end it converted the audio into a datastream (demodulate).

me:
if i want a historical review ill to find it in an ather place

stevez:
With your transceivers you'd be limited to one way communication however you could use two pairs for two way communication

me:
pls take a look at that photo is it or not HD 2way com??? IN ONE PAIR???

IF SOMEONE HAVE A GOOD IDEA (electronic idea)ON HOW TO MAKE THOSE 2 BOXES (data to audio mod & audio 2 data dem) PLZ SHARE IT WITH ME!!!!!!

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It's only one way at a time, which means you have to control RX/TX switching as well, you might also consider the legal implications?, are you permittd to send data on the frequency in question? - most usually NOT!.

I suggest you try googling for "packet radio modem", which is what radio amateurs use for data communications, on specific allocated legel frequencies.

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a microphone can be considered as a speaker, so your hand drawn diagram indicates to me that your microphone will function exactly the same as your speaker, because they are connected in series.

You could also do full-duplexing which means two frequencies are required. one for sending, and the other for receiving. But some stations you connect to may not support it which in that case, use Nigel's idea.


I searched for that myself. The best I got was a circuit for an interface between the computer and the radio (a.k.a. a ridiculously simple TNC)

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

 

"It's only one way at a time"
i know that "pls take a look at that photo is it or not HD 2way com"
the HD=half dublex
BUT I REALY THANK YOU FOR "packet radio modem"!!!!!!!!!
THANK YOU SO MUCH I FOUND WHAT I WAS LOOKING FOR!!!!
THANKS AGAIN!!!!!!! FOR MY NEXT QUESTION I'LL PM YOU FIRST!

 

An electret mic can't be used as a dynamic speaker, but a dynamic (coil and magnet) mic can.

They aren't in series. Both are connected to ground.

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Uncle $crooge

 

Like most of the answers msecha writes everyone needs to be corrected. Looks like he should get off the organic smokes and go back to school well pre-school should be a good start

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" The only way to avoid human error is to avoid the use of humans"

 

Many of us Ham Radio Operators were treated to a new digital mode invented by a gentleman in the UK several years ago called PSK31... It's very narrow bandwidth provides an excellent signal-to-noise ratio and many of us have acheived some very nice low power/weak signal contacts with it... Best of all, it utilizes the DSP capabilities of the sound card in your PC and connects easily from the sound card to the audio connectors on our transceivers... It also works quite well from PC to PC simply using speakers and mics' on both PCs (grin)...

Try googling PSK31 and download one of the many free PSK31 programs...

Have fun... Regards, Mike

 

normally I don't answer completely wrong, but this time I did, because his ground symbol was not a standard one, and his circuit looked like he drew it in 10 seconds.

When I was answering, I missed the ground symbol.

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

 

Hi MStechca,
You're forgiven this time. :lol:

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Uncle $crooge