Abgeschickt von David Speight am 30 Mai, 2005 um 14:42:49
Can any one help me?
I have been recieving APT images from the NOAA polar orbiting satellites and decoding them with WXtiImg.
Fin. but one problem is baffling me:
(1) I am using an ICOM R7000, and a homebuilt 1/2 Wavelength Dipole. Each picture I decode is uniformly covered with 'white' noise which reduces picture quality, and when the satellite is directly 'overhead', there is a ~20 degree band across the middleof the picture that is totaly black! i.e. apparently no data.
Now, (if you're still reading) I understand that the bandwidth (?) of the reciever has to be about 25kHz to decode the images, and my R7000 specifications claim a "Selectivity" of +/- 7.5kHz minimum @ -6dB.
Does this mean that the reciever has a bandwidth too narrow for these images? and what is the significance of the black band in the pictures?
Any help extremely appreciated!