Can someone at smartBridges explain the
following?
I ran a little experiment this afternoon. I took an
aBO with a 13db Maxrad panel and put it on a tripod 3800ft from my tower with
clear LOS. The location was 13* off the centerline of the tower's 16db sector
antenna, which meant there was less than 1db of off-center loss. Link
calc comes out to a received power level of -57dbm. I used
Q-check to run speed tests across the link to a Q-check server in my NOC. I
started with the 13db in the same polarization as the tower and then started
turning the antenna to induce cross-pol rejection to simulate distance. I re-ran
the speed test at each angle and recorded the reported RSSI as well. The
results are below.
Here is the really curious part... look at the 70*
line. The antenna rotation had induced about -13.2db of
gain making the received power level about -70dbm. The reported RSSI is -23
and the thruput has dropped to 45K... what the heck? Why 45K at a reported
RSSI of -23db? and no data at all at a reported RSSI
of -27db?
Dave
| Degrees Rotation | Induced
db loss |
Reported
RSSI |
Thruput (Kbps) |
| 0 | 0 | -10 | 3390 |
| 30 | -2.7 | -10 | 3407 |
| 45 | -5.9 | -13 | 3310 |
| 60 | -10.0 | -19 | 1730 |
| 65 | -11.5 | -21 | 1327 |
| 66 | -11.9 | -20 | 1070 |
| 67 | -12.2 | -21 | 263 |
| 70 | -13.2 | -23 | 45 |
| 75 | -14.8 | -27 | 0 |
