User's Manual

Configuration
Trango Broadband Wireless — ATLAS4900 page 12
- Twice per second while in opmode ON and scanning for an MU or RU.
- Solid after unit is associated with the RU or MU.
RF Link Loopback Test (linktest command)
The linktest command tests the throughput and packet error rate (PER) on the current channel for each direction at all
speeds and reports results. This command also provides RSSI for both ends of the wireless link. The command can be
run from either the MU or the RU.
In running the linktest command the user must specify the modulation speed for each end of the link.
Command format: linktest <loc speed> <peer speed>
Valid modulation speeds are: 6,12,18,24,36,48, and 54 Mbps. Lower speeds will result in fewer dropped packets.
Example:
# linktest 24 24
local tx rate = 24 Mbps
peer tx rate = 24 Mbps
packet size = 1600 bytes
# of packets per period = 1000
# of Cycle = 10
0> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
1> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
2> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
3> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
4> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
5> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
6> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
7> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.00 Mbps
8> [tx] 1000 [rx] 1000 [rssi] -36 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
9> [tx] 1000 [rx] 1000 [rssi] -37 peer: [tx] 1000 [rx] 1000 [rssi] -40 -> 22.01 Mbps
--> [tx] 10000 [rx] 10000 [rssi] -36 peer: [tx] 10000 [rx] 10000 [rssi] -40
--> [Local PER] 0.00 % [Peer PER] 0.00 %
Success.
#>
In this example the linktest was run at 24 Mbps at each end of the link. The results indicated 10 cycles of 1000 packets
were transmitted and received from each end of the link without error. Actual achievable throughput is measured at 22
Mbps.
Link Speed & Power Settings
Users may change the radio’s over-the-air data rate and conducted output power using the speed and power
commands. Keep in mind that the lower data rates offer higher receiver sensitivity and higher allowable
conducted RF power in the ISM band. The following table shows the relation between speed settings, receiver
sensitivity, and allowable maximum power settings for each band. The lowest power setting for all bands in –4
dBm.
Speed Setting
(over-the-air rate)
(Mbps)
Receiver
Sensitivity
(dB)
Max Power
High (ISM) Band
(dBm)
Max Power
Low (U-NII)
(dBm)
6 -92 21 7
12 -87 19 7
18 -85 19 7
24 -84 18 7
36 -80 18 7