Walky-talky without using inductor or coil

Walky-talky in this website is world 1st verified walky-talky project without using coil. Walky talky is very interesting and attain grabbing project for electronics hobbyist. Communication is done without any physical connection and mobile network up range of 500 meter. Almost all communication devices utilize coil which is burden for electronics hobbyist. So, we design this circuit without using any coil.

Circuit Descriptions of walky-talky

The entire circuit of walky-talky is divided into two main section transmitter and receiver section.

Transmitter section:- Transmitter section utilize  IC NE566 (IC4) as VCO (Voltage Control Oscillator) for generating frequency about 30 KHz. Resistor R24 with Capacitor C24 used as frequency components for frequencies determination. Voice is pick-up by mike (MIC1) and changed it into equivalent electrical signal. Signal from microphone is amplified by transistor T4 and given to pin no 5 0f IC4. NAND gate N1 with crystal oscillator XT4 finalizes the output from pin 3 of IC3. Lastly, signal from NAND N2 through N3 and N4 given to antenna for transmission.

Receiver section: - Transmitted signal from another walky-talky is received from same antenna which is used for transmission. Field effect transistor T1 boosts the received signal and make more powerful and send to amplifier section made from transistor T2 and T3 with crystal oscillator XT1 through XT3. Detector section is made from diode D1, Capacitor C6 and resistor R12. 30 KHz frequency is obtained from detector section.

Frequency of Phase Locked Loop IC NE565 (IC1) is adjusted by capacitor C9, resistor R17 and variable resistor VR1. Amplifier IC LM386 (IC2) is used to amplify the signal and given to speaker.

PARTS LIST

Resistors (all ¼-watt, ± 5% Carbon)

R1 = 47 KΩ

R2 = 100 Ω

R3, R4, R11, R27 = 2.2 KΩ

R5 = 330 KΩ

R6, R10 = 560 Ω

R7 = 1 KΩ

R8 = 220 KΩ

R9 = 100 Ω

R12, R15, R16 = 4.7 KΩ

R13, R31 = 10 KΩ

R14 = 15 KΩ

R17 = 1.8 KΩ

R18 = 1.2 KΩ

R19 = 1 KΩ

R20 = 4.7 Ω

R21, R22 = 100 KΩ

R23 = 120 KΩ

R24 = 5.6 KΩ

R25 = 22 KΩ

R26 = 150 KΩ

R28 = 330 Ω

R29 = 220 KΩ

R30 = 47 KΩ

VR1 = 4.7 KΩ

VR2 = 22 KΩ

Capacitors

C1, C6, C10, C24 = 1 KpF

C2, C4, C5 = 47 KpF

C3 = 20 KpF

C7, C9, C23= 2.2 KpF

C8 = 4.7 µF/16V

C11 = 22 KpF

C12, C16 = 0.1 µF

C13 = 2.2 µF/16 V

C14, C19, C25, C26 = 0.22 µF

C15 = 10 µF/16V

C17 = 220 µF/16V

C18, C20 = 10 KpF

C21, C22 = 68 pF

C27 = 1000 µF/16V

C28 = 10 µF/16V

Semiconductors

IC1 = NE565 (Phase Lock IC)

IC2 = LM386 (Amplifier IC)

IC3 = CD4011 (Quad 2-input NAND Gate IC)

IC4 = LM566 (Voltage Controlled Oscillator)

IC5 = LM7812 (Voltage Regulator)

T1 = BFW10

T2, T3 = BF194

T4 = BC148

D1 = 1N4148

Miscellaneous

XT1 – XT4 = 10.7 MHz crystal

SW1 = Single pole double throw switch

LS1 = 8Ω speaker

MIC1 = Condenser microphone

Areal

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62 thoughts on “Walky-talky without using inductor or coil”

1. Archanagond412 says:

thanks sir…….

2. Mahesh kunwar says:

is this correct ckt?

yes the circuit is 100% working.

1. kalpa kr sonowal says:

thx 4 the ckt…:)

2. kalpa kr sonowal says:

sir what is the maximum range of this circuit…

3. rahulkushwaha says:

tell me range sir

4. Tatang says:

Hi ..
It’s interesting circuits but I’m wondering about the interference effect to public FM radio receiver, since it’s use 10,7 Mhz Frequency carrier ..
Is there any info regarding this ?

BR//Tatang

1. Here we are using the Intermediate frequency band with frequency 10.7 Mhz for transmission and the public FM in most countries uses VHF band for FM broadcasting , So it should not be a problem in most countries.
The Frequency is also used by some Satellite and FM broadcasters in some few places ( Which I haven’t heard of till now) .
But I suggest to make sure that the frequency 10.7 mhz is not used by any other broadcaster in your place before building this project.

5. Tapan says:

6. prathamesh says:

wats the range of thi walky talky sir

1. As written above in the circuit description the range of the walky talky is about 500 meters.

7. Sattwik Jana says:

i like this project

8. tapan says:

what is the use of nand Ic???…and if you have circuit explanation please provide us….

1. The use of the NAND gate here is for construction of a simple oscillator with the help of the Crystal (XT).

9. LALIT SHARMA says:

1. What is the aerial antenna and what are its specifications for buying it so that it can be used in the above circuit??
2. Is it possible in this circuit to transmit or receive the signal at a time???
3. can you elaborate the working of the complete design circuit (not the working of vco, amplifier, etc.but the working of what mode in which it receive or in what mode it transmit)?????????

Thanks

10. LALIT SHARMA says:

what parameters are defined to buy the aerial antenna so that circuit works properly???????

11. LALIT SHARMA says:

NICE

12. LALIT SHARMA says:

13. Sandeep reddy says:

Hi sir,this is excellent.i’m not an electronic student but i am interested in doing these projects.Is there any chance in increasing range.

14. LALIT SHARMA says:

.

15. LALIT SHARMA says:

hello

16. LALIT SHARMA says:

ckt not working

17. murali krishna says:

how to increase the range

18. JOhn says:

Sir what kind of antenna?

Thanks…

19. Aqeel says:

can u please explain function of each component of this circuit…..
I mean detailed working of the above circuit…

20. john says:

Sir…. what kind of antenna i might use in this walky talkie… Thanks..ASAP!

Good evening sir,
Is it legal to work on this frequency in india. I mean, i will be not the violation of rule?

22. gurudev says:

hi sir,
can i get circuit with inductor or coil????
is it simpler 1 than this circuit!

23. Irfan says:

Layout sir

24. SIddhant Badode says:

what is the range of the circuit ?

25. LALIT SHARMA says:

hi
I have a question
XT1-XT4 means crystal quartz.? crystal quartz have two pin but this part have 3 pin? why?

27. Akshay says:

Can the 10.7 Mhz crystal be replaced with 10.24 Mhz crystal

28. Sakar Pudasaini says:

Which modulation is used by this circuit to transmit and receive signals FM or AM?

29. Akshay says:

Is XT a ceramic resonator??

30. Learner123 says:

Sir which type of communication is used in this circuit ?? I mean RF or something ??

31. biju says:

how much is the value of ‘KpF’???

32. Learner123 says:

Sir Plz do reply, I have few questions !!
1) My NE566 IC heated up like a burning coal whenever i applied the voltage, i have checked every single connection, i have done the connections exactly instructed in the circuit, so whats the problem? Is it normal?
2) Any equivalent of BFW10? in my area there is no BFW10 available so i am using BC246A. Is it correct? Because BC246A is also N-channel JFET, can U recommend any equivalent??
3) Can i use 11.0592Mhz crystal instead of 10.7Mhz ???
Please sir do reply urgently, I have to submit this project within a week.

33. clark says:

Is there 10,7MHz crystal or ceramic filter? As i know 10,7MHz is a ceramic filter (CF). Or maybe i dont know if 10,7MHz is crystal too. And how about pin number if that is a ceramic filter (CF)?

34. hello,
can you please provide me the complete description, use & working of each component of this project.on my registered mail ID.

I’ll bethankfull

35. V.Sambath kumar says:

Sir, can i connect an audio signal direct to the mic input point after removing the mic.
hope 500 mtrs range will not violate the fcc rules,is the transmission free from disturbances,is a thin shield
metal cover grounded to the negative supply required for any section to avoid noise and disturbances,what is the min and max current drawn by the circuit when the system is on ideal cond and current during transmission /receiving . Regards Sambath kumar.

Pls tell me the alternate IC’s for NE565 and LM566. That is not available in our place

37. salah badr says:

sorry, how can i calculate frequency?
the frequency at Tx as same as Tx ?
thanx alot 😀

1. salah badr says:

Tx as same as Rx

38. daramora says:

What is the unit KpF used in capacitors value? What is the equivalent in uF or pF? Thank you

39. Sir i want circuit making video if any on youtube
And also can i used 25v capacitor instate of 16v capacitor.

40. Sir can i use bc548 & bf494 instant of bc148 & bf194.

42. please sir tell me about why crystal oscillator is used in this ckt????

43. Please sir tell me What is the use of crystal oscillator in this ckt please sir its very important.

44. jeffrey marius says:

How is that you build these circuits? I mean like how yo know where to play e the resistor and the values of the resistor , though I know that its done by calculation how to actually build these complex circuits on my known. I am sure my questions is difficult to answer or could nor be explained in a comment so please at least direct me to the materials that can help me develop these skills of building and designing circuits on my own. Your help would be appreciated and beneficial. Please reply me positive. Thank you very much.

45. MEHEDI says:

what is the funtion of lm566 BC194 BWF10??
is there any alternative IC please inform me…

46. jeffrey marius says:

I am a novice in electronics. Well concerning the circuit it contains an oscillator with three pins can a two pin oscillator also be used.

47. Cryptic says:

Hi,

I am struggling to find the transistors – T1 = BFW10; T2, T3 = BF194; T4 = BC148. Could you please suggest any other models that wiould replace these. Thanks in advance.

48. Cryptic says:

I am struggling to find these T1 = BFW10; T2, T3 = BF194: T4 = BC148 transistors. Any suggestions that could replace them. Thanks.

49. Vivel says:

Sir What should i use for antenna…..i built the whole circuit and i am struck in antenna……..plssssss help !!

50. Sir,

could you please specify the antenna buying specifications

51. En says:

Hello Sir, can you please message me regarding the antenna? What is it actually? and what type of modulation is used in this circuit? Is it guaranteed that this scheatic works? Thank you for the response, hope can have it sooner 🙂