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micro
04-16-2007, 02:49 PM
Hi all,

I need to know whether it is possible to construct a small device using minimum components to get something like a walkie talkie - the kind of thing they keep using in movies to communicate among themselves. (Just like a device with which a solder keep communicating with his mates while doing a stealth operation. :wink: )

If yes, what would I need to construct such a device. I need only a short distance communication, maybe a 50 to 100 mts.

Please provide me with links.

Price lists of components also expected.

Thanks.

Ulhas
04-17-2007, 11:36 AM
look for fm trx on this link

http://www.electronicsforu.com/electronicsforu/lab/default.asp

and also look some previous issues of the same magezine for super simple FM receiver. Only one additional thing you have to do is change the trx frequency of trx and rcx.

Both trx and rcx is small enough to mount inside the cabinet

regards

ulhas

micro
04-17-2007, 12:30 PM
I am sorry, but Iam a bit confused :?: 8O :?:

Can you please tell me the name of the circuit... I am not familiar to terms like "fm trx". I think its "FM Transmitter". I searched for the word on the page I found three occurrences of the same. I hope, you referred me to "Medium-Power FM Transmitter" http://www.electronicsforu.com/electronicsforu/lab/ad.asp?url=/EFYLinux/circuit/aug2005/CI-01_Aug05.pdf&title=Medium-Power%20FM%20Transmitter

Neways, thanks.

docel
04-18-2007, 12:44 AM
1. Trx & Rcx are "wrong" notations/ terms for Transmitter (Tx) Receiver(Rx) and Tranceiver (TxRx) by Communications protocol.

2. The 'minimum' component' Tranciever ( Handie) used by the 'solder" is a sophisticated communication equipment that is a combo Tx/Rx, about at least 5W Rf PO, Encrypted/Scrambled AF/IF, Spread Spectrum ( where the AF is transmitted across a 'wide' band of frequencies running into several MHz's!!!)
These are true Communication tech marvels and are NOT simple!!!
3. They cost a LOT OF MONEY TO BUY ( but are restricted by stringent WPC, Min. of Comm. rules)
4. Ordinary humans can NOT EVEN SEE them, according to the Rules.
5. There is a Legal limit of 10mW for non-licenced TX, Special SWL licencing to possess a "HF/VHF/UHF Rx....if you are polite and law abiding. :oops:
6. MAKING a VHF RX is Not in the students domain, due to lack of proffessional RF equipment and expertise.
7. Human Voice channels are thus prohibited for both Tx and Rx. These things can ONLY happen in movies. In real life, you can get away with TxRx in the ISM frequency bands. The appropriate frequencies are subject to Local Wireless rules and regulations and are NOT standard across the globe.
8. Your requirement is for a Walkie-talkie. The suggestion by Ulhas is for a Data only TxRx!!!