[amsat-bb] NOAA Weather Satellite receiver

[Kevin Schuchmann]

    Pick pretty much any 2m FM receiver design you like, recalculate the 
front end and
  your mixer for 137.5 MHz and then adjust the I.F. bandwidth to 40 KHz, 
APT is  a 2400 Hz
carrier  that is Amplitude Modulated on a FM Carrier at 87% modulation 
which makes
it about 34 KHz wide, any receiver design should have AFC or some sort 
of frequency
control  to compensate for Doppler or you will need to make your I.F. 
filter a little wider
to keep the signal in the passband.

Kevin WA6FWF

A good example is the RX2 
http://www.time-step.com/rig//pdfs/rx2c%20instruction_20.pdf

On 12/5/2014 1:34 AM, Rupesh Lad wrote:
> Hello all;
>
> I am an undergraduate Engineering student and a SWL. I have tracked many
> Amateur satellites from COEP Ground station, VU2COE.
>
> I want to Home brew a NOAA satellite image receiver as my academic project.
> I will be using WXtoImg to decode the image transmitted by NOAA satellite
> on APT frequency. So the task for me is to get the audio frequency output.
>
> Literature says that NOAA satellites transmit a signal of 40 kHz bandwidth.
> I have also observed the spectrum on Spectrum analyzer using my antenna.
> Want to know whether this is only RF bandwidth? and if it is so, then what
> is IF bandwidth of such signals?
>
> Can anyone help us in designing the receiver?
>
>