Receiver for NOAA weather satellite

Hi,

I am new at RF. I read from books that the IF can be shifted by mixing a frequency with the input frequency.
I am curious that there's 87-107MHz IC. If I mix the 137Mhz input with an oscillator, say, 45Mhz, is it possible to get the sounds signals from the satellite?

Thanks.

A commerical FM receiver will have too wide a bandwidth. The old NOAA system uses a narrow bandwidth FM. The channel bandwidth is about 50 kHz. This is in comparison with 150 kHz for commerical FM and 20 kHz for a normal FM communications scanner which is too narrow.

Your best bet is to convert to 10.7 MHz I.F. and get a filter of 50 kHz to 60 kHz nose bandwidth. The demodulator can be a quadrature detector, just raise the Q of the quadrature coil circuit to reduce the bandwidth which will increase the recovered signal level.

Might be worth checking the broadcasts are still running. Several satellites have gone completely digital now and it is very difficult to decode the data.

Brian.