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Why my RF circuit does not function?

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E-design

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Re: rf circuit not function

Here are a few tests you can do. Having a scope and a frequency counter will be very helpfull.

As the transmitted and received data is controlled by a PIC micro, you can start by
1. Connect the GND connections of both circuits together.
2. Connect a piece of wire between pin3 (RA4) and top of R3 (10k)
3. Press SW1 or SW2 and see if any of the relays RL1 or RL2 operate. There should be pulses on RA4
4. If that that works, you know the pic micro and program is functioning correctly
5. If that does not work, make sure that the comparator IC1 (LM358N) is feeding square waves to pin18 (RA1) when you press one of the buttons. If the square waves are present, you may have a faulty micro, 4MHz crystal not oscillating at the constant frequency or sporadic, or micro is not properly programmed. Pin RB5 and RB7 should go high/low in turn when you keep pressing the buttons.
6. If step 4 worked, you will need a scope and/or frequency counter on the antenna connection (collector TR2). With a scope look for bursts of RF when you press a button. You may also break the connection to pin RA4 to keep TR1 on all the time. This way you can measure the constant RF and determine the frequency with a scope or frequency counter. If there's no RF then the oscillator stage (TR1) or buffer stage (TR2) is not working.
7. Next you can check if this RF frequency passes through the receiver stages TR1,2. You should have a strong RF signal on LHS of C6. This will only happen if the resonant circuit (L1 & C1) is tuned to the same frequency coming from TR2 (ANT connection). You should adjust L1,2,3 for max RF on LHS of C6 using a scope with high enough bandwidth. If you lose the signal someplace, look for a problem in that region (wrong component, building mistake etc.)
8. Remember to reconnect RA4 and seperate GND's when you get all of the above sorted out before testing unit for proper operation

After typing all of this above I found the site also give hints and tests for this product https://www.hobby-elec.org/e_pic6_8.htm
Testing the TX oscillator: https://www.hobby-elec.org/e_pic6_8j.htm
Testing receiver: https://www.hobby-elec.org/e_pic6_8k.htm
 

zawani

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Re: rf circuit not function

sir try this projek but circuit not funtion also. i think code proggramming for pic not error but not funtion la can you help me check they programming
 

E-design

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Re: rf circuit not function

You must use the remocon_hex.zip and remo_r_hex.zip files of the project to program your PIC micros after unzipping it. Make sure that you select the correct device if you use a programmer like the PIC-start or similar. You must also set the configuration bits correct as well as the type of oscillator.
 

    zawani

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