My question is with regard to the 1x / 2x modes on this particular model and the jitter readings.
I just deployed a 5.4ghz 20mb back haul. These units are approx. 9,900 feet or 1.8 miles apart. These devices have the 8.1.4 firmware on them. When they are locked into each other, they see an average of 2200+ RSSI, -31Dbm and jitter of 1 ( While in 1x mode). When i change the mode of these devices to 2x, my rssi and Dbm stay the same, but my jitter rises to about 6-9. Is this normal behavior for this hardware? Is this a firmware bug? Is jitter 6-9 acceptable operating ranges for this model of back haul?
Any help would be duly appreciated.
Perfectly acceptable. Anything under 9 is fine in 2X
I am going to take a guess and assume you are using reflectors on these? The reason I ask is that -31dB is actually overloading the receiver on the radio.
I would suggest lowering the Tx power to Low Power (-18dB reduction it Tx power) which will bring the radios down to about -49dB which is still a little hot, but will be rock solid.
Lowering the power is actually better than removing the reflectors. The reflectors reduce the beam-width to about 8 degrees which helps in rejecting off-axis noise.
I appreciate your prompt response. I was a little concerned due to my jitter bouncing all over the place. If anything 9 and under is good in 2x mode, then i should be good to go.
Again, I thank you for your help.
Go with Jerry’s recommendation and lower the power, too. We have found that a link that’s too hot can be unstable just like a link that’s weak. You can pick up a lot more multipath with a really hot signal.
I have reduced the power on this link substantially. I now see about 1400 rssi, jitter 1 and -51 to -53 Dbm on this link. It appears to be rock solid and passing traffic flawlessly.
Thanks for the help guys,
please jerry or anybody, how can i low the power of TX in a BH.
Thanks for your response
On the config page, there are two power options, it’s labeled Power Control (in 7.3.6, anyway…) and the options are low and normal. I believe that low drops power output by 18dBi.
Take time to read the manual…
As Jerry mentions, more isn’t always better. Turning up the power can sometimes just turn up the problems, for you and your neighbor.
A related comment - 5.4s have had adjustable power in 1 dB increments since the beginning. This gives better transmit power control than the normal/low 18 dB drop in 5.7 P9 modules, for example. With P10, all frequency bands get adjustable power in 1 dB increments.