What could be causing my RF transmitter and receiver to not work?

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SUMMARY

The discussion centers on troubleshooting an RF circuit using the T5-434-5V transmitter and R5-434-5-128 receiver, along with the HT12E and HT12D encoder and decoder. The user reports that the RF pair is non-functional despite successful direct connections between the encoder and decoder. Key suggestions include measuring current through the transmitter and receiver, using a scanner to check for 434 MHz signals, and verifying circuit connections to avoid potential damage. Resistance values for the HT12E and HT12D oscillators are noted as 1M ohm and 51K ohm, respectively.

PREREQUISITES
  • Understanding of RF circuit design
  • Familiarity with the HT12E and HT12D encoder/decoder pair
  • Knowledge of measuring electrical currents
  • Ability to use a frequency scanner for RF signals
NEXT STEPS
  • Measure current through the T5-434-5V transmitter and R5-434-5-128 receiver
  • Learn how to use a frequency scanner to detect 434 MHz signals
  • Research common issues in RF circuit connections and troubleshooting
  • Consult with a local Radio Amateur for hands-on assistance
USEFUL FOR

Electronics hobbyists, RF engineers, and anyone involved in building or troubleshooting RF communication systems.

jasonchong0
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Hey all!
I have just constructed a RF circuit to try out. I made use of the T5-434-5V and the R5-434-5-128 transmitter and receiver pair and also the HT12E and HT12D as the encoder and decoder for the transmitter and receiver respectively.

The schemetic I used can be found on page 6 of this datasheet: http://www.spelektroniikka.fi/kuvat/T5R5-434-5V.pdf"

After following exactly, the circuit does not work. I connected the DOUT of the encoder and the DIN of the decoder directly and it works, which brings me to suspect it's the RF pair that's not working.

HT12E oscillator resistance: 1M ohm
HT12D oscillator resistance: 51K ohm

If anyone has any idea as to why the transmitting and receiving isn't working, your comments would be greatly appreciated!
Thanks!
 
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Can you measure the currents of just the transmitter and the receiver? This might give a clue.

Also can you listen on 434 MHz with a scanner receiver? This might help to decide if the transmitter was working.

Did you get the connections wrong when you built it and then correct them after applying power? This could have damaged one of the circuits.

What were those resistance values you gave? They seem high if they are the power supply connections.

Realistically, though, you will probably need to get local help. A Radio Amateur might be able to help if you can find someone who has equipment for 432 MHz
 

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