I am planning a PTP link (29.7km) LOS profile is good.
I intend on using PTP850E. My current link planner setup is as follows:
Maximum Modulation: 256QAM
Minimum Modulation: BPSK 0.5
Hi: Site 1
Using 2ft Single Pol 50.8dBi on both ends.
Site 1 Tx Frequency: 85435
Site 2 Tx Frequency: 75435
Aggregate IP Throughput: 5.144 Gbps
Lowest Mode Availability. 79.9748%
Now the Min IP Availability Predicted for site 1 is 78.0661% and Site 2 is 80.5607%.
The IP throughput im very happy with as this site is intended to move alot of traffic (it links a mesh network with about 200 e500, e510 & e700 AP) so it will be the backhaul to the Fibre link. My question is the Lowest Mode Availability is it in a safe bracket. Im new to cambium and the linkplanner i just want to know if proceeding with this installation would be considered sufficient and stable.
The PTP 850E is a great product for high capacity, however as it works in the 80 GHz band it is expected to be used on relatively short links. Your link at nearly 30 km is much longer than we would typically expect to use for 80 GHz (although it does depend on where it is in the world and what the rain rate is in that area).
For high capacity backhaul links most operators are looking for availabilities above 99.99% (often described as four nines), which allows for ~52.5 minutes downtime per year. High availability links running at 99.999% will be looking for less than 5.25 minutes outages a year.
The availabilities you are getting equate as follows:
- 78.0661 % will result on average in a total outage of 80.1 days/year
- 80.5607% will result on average in a total outage of 71.0 days/year
You can see this information in the hover-help when you move your mouse over the Min IP Availability Predicted text in the Performance Summary panel.
How much outage an operator is willing to tolerate is dependent on a number of factors, but it would be unusual for these amounts to be considered acceptable.
If you have to run a single hop over this distance you should look at coming down to a much lower frequency band.
I would recommend that you get in touch with your local Cambium representatives to work out alternative options.