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A collection of thoughts, and my notes about experiments and ideas, technical or otherwise, connected to Amateur Radio, Satellite working and monitoring and other electronics.

Showing posts with label image frequency. Show all posts
Showing posts with label image frequency. Show all posts

Saturday, July 11, 2009

S-Band filters have arrived

I picked up the S-band filters on the post office today, and it turns out that there are indeed two different filters

1) Centre frequency 2125 MHz, Bandwidth 295 MHz (I assume 3 dB B/W)
2) Centre frequency 2375 MHz, Bandwidth 295 MHz

I tried both filters and it looks like the lower freqeuncy filter does not - to a sufficient amount - attenuate the unwanted signals, so I will use the second one .

The GSM sidebands have completely disappeared, much to my relief. (Not a trace of them in the spectrogram). I need a bit more amplification, but that is easily arranged using a second satellite TV in/line amplifier.


It looks like my theory of insufficient image rejection in the receiver is correct.

Now for some S-Band satellite signal hunting - and of course the LRO on S-Band.