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RF problem with interference between transmitter & recei

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Member level 2
Feb 21, 2002
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RF problem

I have a 433.92Mhz transmiter .On a other site have a Reciver.It is new but it have very much interfenece. Because? PCB? GROUND or it need a protocol?
Thanks in advance

Can you more precise describe your receiver ? Is it super-regenerate, single conversion... ? What is the data rate you are now using .....

Is it meet your target sensitivity?

It is a Saw RF Transmiter

square wave modulation = 3khz
modulate on-off
RF carrier with digital signals

It is AUREL component.

The reciver is aprox. the same expecifitations. It is too form AUREL.
I'm using 1200 baudrate.

If the Tx, Rx are standard off the shelf units, the reason could be power supply and grounding. The PCB/protocol problems will arise only if u have tampered with the units. So give more information about, test setup.

I have to agree that poor grounding is highly possible. Sometimes it could be due to poor decoupling..

What are the AUREL part numbers?

How are you connecting them to RS232 signals?

If the noise is sound likes a high frequency audio sound, it is most likely came from the microcontroller control the 433MHz transceiver. If the noise is random in nature, either your channel is not correctly tuned or your grounding is poor.

As it is an open freq. band, isn't it possible that another 433.9 MHz transmitter works nearby ?

what does it mean "a grounded problem"?

try this

One trouble shooting approach is to put an ear phone on the demodulator output of the recceiver and see what you hear. Another is to put the transmitter and receiver in the same room and try to communicate. From the first test you can tell if some other signal is on the frequency. From the second test you can tell if it is some protocol problem. An oscilloscope would be useful to trace the signal. Is it what you expect at each point?

We had a problem once where harmonics from the uP pcb on the other side of the RF pcb got into the I/P as harmonics from the XTAL osc. This was strong enough to swamp the RX I/P. Putting a HPF directly on the RF in of the chip cured it.

Hi. Guys

Thanks all.
The reciver model is 650200208 / BC-NBK from
**broken link removed**
The transimiter model is in this fpf
**broken link removed**

Thanks all.
Best Regards cb30

This ancient thread never had a solution, but I have same problem: I'm using an **broken link removed** and I see very high noise on RX pin.
Datasheet says "at least 100.000 pF ceramic capacaitor is needed"; I do not have it, so I used a 0,10 uF polyester cap: is it ok?

What else could interference depend on?

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