Understading of the Link Test

Hi -

I have a client that has:
-70/-71 signal
3/4 Jitter
8.3 miles out
900mhz.

[u:3t29pyde]The following is his link test:[/u:3t29pyde]
Stats for LUID: 3 Test Duration: 2 Pkt Length: 1522
Downlink RATE: 1695744 bps
Uplink RATE: 153600 bps
Downlink Efficiency: 100 Percent
Max Downlink Index: 100
Actual Downlink Index: 100
Expected Frag Count: 6624
Actual Frag Count: 6624
[u:3t29pyde]Uplink Efficiency: 31 Percent[/u:3t29pyde]
Max Uplink Index: 100
[u:3t29pyde]Actual Uplink Index: 31[/u:3t29pyde]
Expected Frag Count: 600
Actual Frag Count: 1882

What can I do to help the uplink Efficiency?

Thanks for you hlep.

Several possibilities:
1. Have you verified that all of your SM’s dB levels fall within 10 to 15dB of each other at the AP sessions page? An SM that too “Hot” will desensitize the AP from being able to pick up signals from weaker SM’s.

For example, if the lowest is -80dB, highest should be -65dB. If you have one or two SM’s with substantially higher levels than -65dB, you should lower those SM’s transmit power a little at a time until they fall within the 10 to 15dB range. The closer the levels are to each other, the better.


2. New interference. You could flip the AP to SM mode, and do a quick spectrum analysis to see what the noise level looks like on the frequency you are using. You might see another frequency that is quieter.


3. The SM transmit signal may be hitting some surface, or the edge of a tree that is affecting uplink only.

Jerry,

I dont’ understand your third answer:
"3. The SM transmit signal may be hitting some surface, or the edge of a tree that is affecting uplink only."
Won’t the downlink and uplink be hitting the same surface?

Not necessarily.

The signal coming from the tower only has to be picked up the surface of the antenna. The received power level at the SM is much, much lower than the transmitted power.

If there is some type of boundary or Fresnel Zone intrusion nearer the SM, it will affect the quality and level of the signal the AP can see from the SM.

Ok that makes sense, thanks.