RF digital data receiver 433 Mhz low noise

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You don't, you buy licence free modules - if you build them yourself you would have to submit them for testing.
 
Nigel Goodwin said:
You don't, you buy licence free modules - if you build them yourself you would have to submit them for testing.

Even a receiver only circuit? Here is the US only transmitter come under various FCC regulations, with the exception that manufactured receivers for public consumers have to block out the cell phone bands, but even that can be worked around by calling it 'communications equipment' or some such loop hole.

Lefty
 
Obviously only transmitters, but if you're buying a transmitter you may as well buy the matching receiver - and the technology involved isn't really within the scope of home construction (ceramic substrates etc.)
 
That's a CMOS inverting buffer, and of no use for a UHF receiver.

You don't appear to have any idea of the difficulties involved?, layout is crucial at these frequencies - you don't wind coils, you use short pieces of wire or PCB tracks for your inductors.

If you need to ask, you aren't capable of building one.
 
Thank you

This is my problem in detail...

I build a project IR remote control transmitter and receiver RC5 protocol with PIC16f628, and I want to make it RF remote control with digital ICs and transistors.

In the transmitter I send the signal with transistor ss9018.
In the receiver I process and amplify the signal with 4049.

But the signal distorts so that the led in my receiver that indicates that signal received run and refer to it's not RC5 protocol and the (PIC) receiver ports didn't response !!!
 

Post the circuit for both transmitter and receiver - but I fail to see how you can expect to build a 433MHz receiver using a CMOS buffer?.

Also have you built them on correctly designed PCB's? - layout is absolutely critical - and I get the horrible suspicion that (like everyone else!) you may be trying to build it on breadboard?.
 
Hi

In the transmitter I send the signal with transistor ss9018.
In the receiver I amplify and modulate the signal with 4049.


But the signal distorts so that the led in my receiver that indicates that signal received run and refer to it's not RC5 protocol and the (PIC) receiver ports didn't response !!!

Note:
The kinds of 4069 ICs in my country is very bad and some of them have 16 pins !!!


This is my schematics:
 

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tohu said:
Hi

In the transmitter I send the signal with transistor ss9018.
In the receiver I amplify and modulate the signal with 4049.

Yes, but the receiver itself uses another ss9018, NOT the CMOS buffer, that's just to give a logic output.

How have you built and aligned it?, like I've said previously construction is absolutely critical, and as crude free running LC oscillators they will require tuning to each over.
 
Even though it is 10Meg the resistor around the 4049 gates may cause oscillation, try a very small eg 10pF capacitor to ground on the 1st gate(closest to RF side)
 
Note:
The kinds of 4069 ICs in my country is very bad and some of them have 16 pins !!!
The 4069 has 14 pins and the 4049 IC has 16 pins. Are they marked incorrectly? Do you have them mixed up in the bin?

[oops.... I just replied to a very old thread.]
 
Last edited:
tohu,
In your infra red link are you modulating the infra red directly with RC5 signals or are you modulating a 32 Khz (Or other frequency.) with the RC5 signal and using the modulated 32 Khz to modulate the infra red. This is the normal way infra red remote controls work.

Les.
 
Warning - Ancient thread.

Tohu has not been here since 2009.

JimB
 
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