I have just made up a mock PTMP scenario to show the difference between using the RF Elements Link Tool and Cambiums Link Planner.
I got very different results. I would like to know if Link Planner is taking into account the Beam resolution on Horizontal and Vertical calculations. Obviously this antenna puts out a conical beam rather than the traditional.
I am gettingt very different results between the 2 as seen in the images attached.
Yes, LINKPlanner uses three-dimensional antenna patterns; the planner cannot assume that the AP antenna is pointed directly at each and every SM that it serves.
Does the RF Elements Link Tool take this into account?
In addition, please note that the Force 200 does not have a 36 dBi antenna--it's closer to 18 dBi.
It is not clear to me what transmit powers the RF Elements Link Tool is using for the SMs.
I apologize for not noticing that earlier--do let me know if you've taken that into account. (The SM Tx power appears to be 11 dBm, so the EIRP would be conventiently close to 36 dBm.)
In LINKPlanner if you look at an individual SM in the Antenna Configuration section on the right hand side it will show the AP Antenna Gain, this is the gain of the AP antenna in the direction of the SM taking into account the azimuth and elevation angles (also shown in the same section) and any mechanical tilt that has been applied to the AP. This AP Antenna Gain value can also be displayed as one of the columns in the Links to Subscriber Modules table.
LINKPlanner also interpolates the gain values based on the frequency. If a channel plan has not been created to allocate a specific channel to an AP, LINKPlanner will use the mid-point of the frequency range for the band and regulation selected. For 5.8 GHz Australia the centre frequency is 5787.5 MHz, although this is likely to only make a small difference in the predicted results.
Looking at the RF Elements Link Tool in the CPE Settings it looks like it is doing a downlink prediction of received power at the CPE and to calculate this it needs to know the gain of the CPE rather than its EIRP, which would be used on an uplink calculation. The first value to be configured in the Gain box I believe does need to be the gain of the antenna as Dave suggested, although apologies the gain of the Force 200 at 5.8 GHz is approximately 25 dBi. This is 11 dB lower than the 36 dBm EIRP you have entered. If you reduce the receive power by 11 dB this will give results around -55 dBm, which are very close to those predicted by LINKPlanner.
You are 100% correct about the CPE gain input feild. That should be equal to the CPE antenna gain number not EIRP. The tool will calc EIRP based on that. Only the AP allows you to input a TX db value. Also, please note our tool is a Link Calculator not a very in depth planner like the Cambium tool. It only gives you general guidence with some simple knobs for MCS, Down tilt, and antenna gain. We find that it is fairly close to what you should see in the real world if you populate as much info as possible. Be sure to change your radio Freq and add a noise floor to get better results.
If anyone has any questions, feel free to reach out.
I noticed that attempting to use and/or select the RF Elements horns within LINKPlanner only works if using any other country besides the US or Canada. So essentially, trying to do a plan based on the FCC regulations of power and frequency requirements will not be based on the FCC / IC rules. I am not sure which other country to select that will have the same power and frequency requirements that are either similar or closely related to the FCC or Canada rules.
So how could you plan or do a fair comparison if the regulatory definitions are different? Which country should one choose that mirrors the FCC regulations?
Seems the LINKPlanner will certainly help to understand where your beam coverage or coverage map will look like. But for a link plan (path profile) to see what your SMs performance or client signals will look like in North America would be inaccurate or not the same as if you were to just use the Cambium sectors.
I am not sure why the Horns are not offered in the list when the country is set to US or Canada. Perhaps Cambium_Rachel can explain or provide a road map on when it might be? We are more then happy to provide extra information about our antennas if needed. Just let me know...
Sorry for the delay in replying. There is an issue with the forum that is preventing me from logging in with my Cambium account (Andrew_Haywood) so I've created a separate account.
We don't currently offer these antennas in the US/Canada because Cambium do not have type approval for these antennas with our products.
