# Failure to receive the correct Preamble

#### bravehamid

##### New Member
HI
I'm using a USRP to receive a signal on the 900 MHz frequency band, but the signal received after demodulation has no preamble. Does anyone know what the cause is?
transmitter information:
Baud rate=10K
modulation = BFSK
deviation = 100K
channel spacing = 350K

#### Pommie

##### Well-Known Member
You may think you've given us all the information required but I've no idea what USRP means. Also, no preamble, no data too?

Mike.

#### be80be

##### Well-Known Member
USRP is a costly SDR radio

There are some cheaper in the $1000 to$2000 range.

Last edited:

#### ronsimpson

##### Well-Known Member
In collage, this is what girls said to me before they walked off "Failure to receive the correct Preamble".

#### unclejed613

##### Well-Known Member
there's
transmitter information:
Baud rate=10K
modulation = BFSK
deviation = 100K
channel spacing = 350K
ok, that's what you need to demodulate the signal, but once that is done, what is the protocol the transmitter is using? this is where sync/preamble/header and data format are defined...