build two RF using Tranceiver IC which can communicate each other!

[Nigel Goodwin]

Do you mean using something like this:

Not at all like those, which are data modules, not voice ones.

 

[Dick Cappels]

200 Meters (1.5 Mhz) is not a very good choice for a walkie-talkie because an antenna that would be physically possible for a person to carry would be very inefficient

 

[transistor495]

Actually it is easy to build a walkie-talkie

I've googled 'walkie talkie circuit' images, and it executed lots of interesting circuits works on different bands. Try it and come with a circuit best suitable for you. You'll get debugging and construction techniques further here.

If it's just for a demonstration for your professor, then an AM transeiver working on 1MHz would be rather easy for you. Transmitter can be a single transistor wired and receiver an op-amp based with an LM386 output driver.

 

[marcbarker]

Not at all like those, which are data modules, not voice ones.

I don't think the OP asked for voice (until we suggested it!), I thought he/she asked for something just needed build two RF tranceiver and both circuit can communicate each other?

I suppose it might work with a data rate of 300Hz to 3 kHz and up to 100 % THD (Loudhailer sound quality).

 

[trennonix]

hello,
i opened up an rc car to try and replicate the radio in it, and i was wondering, why do they build their own inductors, i mean it's alot cheaper to adjust the circuit to work with ready made ones, isn't it?
What am i missing?

 

[Nigel Goodwin]

I don't think the OP asked for voice (until we suggested it!), I thought he/she asked for something just needed build two RF tranceiver and both circuit can communicate each other?

As the post you actually quoted included the requirement "walkie-talkie" twice it rather makes a mockery of that excuse

anyone have idea about walkie talkie?i need to build a 200 metre walkie talkie..can help?

I suppose it might work with a data rate of 300Hz to 3 kHz and up to 100 % THD (Loudhailer sound quality).

It's an offence to use audio over a licence free radio data module.

 

[marcbarker]

As the post you actually quoted included the requirement "walkie-talkie" twice it rather makes a mockery of that excuse

It's an offence to use audio over a licence free radio data module.

I wager the application isn't audio.

Is it really illegal to send voice over licence-free module? I suppose near-instantaneous voice encoding is "voice", while pre-recorded voice soundbytes sent as compressed data counts as "data". I wonder how it'd be enforced?

 

[Nigel Goodwin]

I wager the application isn't audio.

So someone asks for a "walkie talkie" with a 200m range, and you wager it isn't for audio?.

Is it really illegal to send voice over licence-free module? I suppose near-instantaneous voice encoding is "voice", while pre-recorded voice soundbytes sent as compressed data counts as "data". I wonder how it'd be enforced?

Yes, it is illegal, read the terms and conditions for the use of the licence free modules. As with all radio offences in the UK, it would be enforced by OFCOM.

 

[giftiger_wunsch]

It's fascinating how young people, the future of our planet, communicate. The thing is, apparently between peers that form of grammar is 'perfectly' understandable, so in no way am I singling out the OP for any blame. I probably over-reacted anyway, with what appears as my 'shakespearean english' response

Hey, don't stereotype youthful people I for one am happy with my ability to communicate.

Yes, it is illegal, read the terms and conditions for the use of the licence free modules. As with all radio offences in the UK, it would be enforced by OFCOM.

Wow, that law's even more ridiculous than the american law against data encryption

But unless you're broadcasting the phrase "this is an illegal broadcast" and a group of OFCOM officials are walking down the road within 200m listening to the correct frequency, it's unlikely to be enforced.

 

[Nigel Goodwin]

Wow, that law's even more ridiculous than the american law against data encryption

I would imagine the law is probably the same in the USA?, it's a specific licence free data frequency.

But unless you're broadcasting the phrase "this is an illegal broadcast" and a group of OFCOM officials are walking down the road within 200m listening to the correct frequency, it's unlikely to be enforced.

It's likely to be enforced when your long term audio transmissions wipe out legitimate data users in the area - a key fob for a car transmits one burst of data a tiny number of times per day, so many users can (and do) share the same frequency. Talking to your mate is a much longer affair and will cause much larger problems.

 

[giftiger_wunsch]

it's a specific licence free data frequency

You mean a specific frequency which anyone can use without requiring a license? Fair enough then.

 

[marcbarker]

So someone asks for a "walkie talkie" with a 200m range, and you wager it isn't for audio?.

Yes, it is illegal, read the terms and conditions for the use of the licence free modules. As with all radio offences in the UK, it would be enforced by OFCOM.

A far as it's possible to tell from what the OP has written so far, the original requirement is for building "two circuits RF tranceiver" (whatever that is?), but using an IC as a transceiver, so both RF tranceiver can communicate with each other. Somehow. And he/she did mention a 'handphone' =W/T too.

ahyap90 ? Help us help you. Please tell us,.. Do you want specifically need audio involved with your RF tranceiver to communicate with each other?

In my experience, the authorities don't search for individuals transmitting illegally, they only react to specific complaints from other radio users or from local government. There are many 1000's of community radio stations operating in London and if they have a clean signal and behave themselves (not transmit subversive content) on air they are left alone. Sometimes the authorities do have area 'crackdowns' from time to time, but they're not that well carried out. A freind of mine operating a station actually approached a Unit (as a passer-by) who were trying to detect his signal (switched off at the time), and spoke with the 'radio police' for a few minutes about the job they do.

Back to OFCOM, I'm sure they would get involved proactively though with an organisation who was trying to release a consumer product without full RF legal certification. They'd have to it's their job!