[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

RE: Geo Opportunity

>With all the calculations ive done, on all the
>different band i tried, a Geosat
>at ~35k klm
>with a 0dbi gain RX antenna would not be useable with
>anything less then an EME
>class station.
>I may be wrong but i dont think so. 

Only the moonbouncers would be making SSB contacts but
I think the CW and PSK31 ops could be happy, 'tho my
back-of-the-napkin calculations could be wrong. 
Assuming a 2 metre downlink, a 1 dBW ERP (LP) from the
satellite and a 1.8 wavelength long CP yagi in a quiet
location with a good preamp:

satellite ERP 1dBW
path loss -168dB
polarization loss -3dB
transponder loading -10dB
station antenna gain 13.7 (dBic)
antenna/system temperature 500 degrees k
receiver bandwidth 2.7 kHz

10log 1.38E-23 * 500 * 2700 = -167 dB noise power

I come up with a 1dB s/n ratio.  I guesstimated the
system noise temperature using the VE7BQH antenna
table at:


and then I doubled the Ta.

Post your free ad now! http://personals.yahoo.ca
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org