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RE: WEFAX question



I found some information on GOES 8 at 
http://rsd.gsfc.nasa.gov/goes/text/goes.databook.html which states that the 
EIRP for WEFAX and Processed data is 54.9 dBm. Assuming path loss of about 
188 dB at 1691 MHz, and 20 dB of amplifier gain, that leaves a received 
signal level of -113 dBm. If the receiver is full quieting at -100 dBm, the 
antenna system needs to produce 13 dB of gain. I don't know what the loop 
yagi is rated at, but it should be at least that. It's also easy to see 
that just a few dB in the wrong direction sends the whole thing into the 
noise. I didn't notice the polarization in the documentation, but it may be 
circular. You can easily lose 3 to 6 dB by being linear.

AB2S

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