Re: [amsat-bb] RE: Geo Opportunity

[Jim.Walls@xxxxxxx]

Bob Brununga said (in part):
> Uplink 10m
> TX power         25W    43 dBm
> TX Antenna Gain          3 dBi
> Polarization loss       -3 dB
> Resulting EIRP          43 dBm
>
> Path Loss at 10m      -153 dBm
> Receiver Antenna Gain    0 dBi
> Received signal       -110 dBm
> Required for 10dB SNR
>   in 3 KHz bandwidth  -119 dBm
> ------------------------------
> Margin                  +9 dB
>
> Downlink 2m
> TX power         5W     34 dBm
> TX Antenna Gain          3 dBi
> Polarization loss       -3 dB
> Resulting EIRP          34 dBm
>
> Path Loss at 70cm     -167 dBm
> Receiver Antenna Gain   15 dBi
> Received signal       -118 dBm
> Required for 10dB SNR
>   in 3 KHz bandwidth  -120 dBm
> ------------------------------
> Margin                  +2 dB

Bob, you shorted yourself on both the uplink and downlink.  25W is 44dBm
not 43dBm (although you did not include feedline loss).  On the downlink,
5W is 37dBm not 34 dBm (although again you did not include any feedline
loss, but I would expect that to be small since it's not exactly a long
feedline run on board a satellite).  Just to keep someone from splitting
hairs, these numbers are rounded off, but are accurate to within .025 dB

73
-----------------------
Jim Walls - K6CCC
k6ccc@amsat.org
Mobile Radio Operations
Southern California Edison Co.
Ofc:   626-302-8515   -   PAX   28-515
FAX:   626-302-7501   -   PAX   27-501



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