<snip>
Charles,
Your point is well demonstrated,
except....
>6'
Dish: +34 dBi
Not sure what dishes you
are talking about, You can get 34 dbi out of an Andrews 3 footer.
With 6 foot you should be able to get > 37
dbi.
</snip>
Lol --
you're right
after
not sleeping for a week -- I guess I'm allowed to make a mistake
<wink>
-Charles
-------------------------------------------
The main difference is that the spectra requires 30 Mhz of ABSOLUTELY
CLEAN SPECTRUM in both the vertical and horizontal polarities (150 Mb "Air
Rate" transmits on V-pol & 150 Mb "Air Rate" transmits on H-pol -- cut
off 1 polarity, you halve throughput)
In
addition, the Rx sensitivity of the Spectra at the 300 Mb data rate (256
QAM) is -59 dB with an output power of +18 (so you'll need HUGE dishes to
guarantee the link budget)
So, lets do a "theoretical" path calc / comparison (15
miles)
11
Ghz Licensed Link (100 Mb Full Duplex)
Rx
Sensitivity: -76 dBm
Tx
Power: +21 dBm
4'
Dish: +39 dBi
Expected RSSI: -42.9 (>30 dB of fade margin = ROCK SOLID LINK
=)
5
GHz Spectra
Rx
Sensitivity: -59 dB
Tx
Power: +18
6'
Dish: +34 dBi
Expected RSSI: -49.4 (~10 dB of fade margin w/ 2' more of each
dish)
Then there's all sort of "real-world" performance issues that occur
with higher-order modulation schemes and license-exempt
operation
-Charles
-------------------------------------------
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