PTP820s Tx level

In the PTP820s, the Tx level must be 27dBm according to the linkplanner but the limitation in the radio is (2…26) dBm so I chose 26


But the operational Tx level is 21dBm not 26dBm knowing that the ATPC is disabled that’s mean it’s must be choose the biggest value of the power! And that’s affect the Rx level which is must be -32dBm but we get -42dBm.

your suuport will be appreciated...

Hi Almajidi,

From your screen shots I can see that you have Adaptive Transmit Power enabled. This is a different feature from ATPC and allows the radio to change the transmit power based on the modulation mode being used. When you configure the radio you must enter the maximum transmit power for the minimum modulation mode you have configured in order to take advantage of this feature. The radio will then automatically change the transmit power depending on the modulation mode in use at that time and this is the value shown in the Operational Tx Level.

LINKPlanner takes into account the different transmit power levels for each modulation mode when it calculates the fade margin and availability for each mode.

The PTP 820S Technical Description has a table in Chapter 7 under Radio Specifications – Transmit Power Specifications, which shows the maximum transmit power that can be used by each modulation mode. This table shows that for an 11 GHz link if the link is operating at 21 dBm it is in 2048 QAM. Further details on ACM Adaptive transmit power control is given in the same document in Chapter 4 under Innovative Techniques to Boost Capacity and Reduce Latency – Adaptive Coding Modulation.

Can you please confirm what value you have configured for the minimum modulation mode on the radio? If the minimum mode is configured to 16 QAM, this will explain why it is only allowing you to set the maximum transmit power to 26 dBm.

You say that the Rx Level should be -32 dBm, but you are only getting -42 dBm. If you planned the link at 27 dBm and it is now operating at 21 dBm, you should only be 6 dB lower than planned and not 10 dB.

If you would like us to review your LINKPlanner project file, you can send this to



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Hi Rachel,

Thats mean if i want to reach to 27dBm the modulation must be 8PSK according to the list!

The minimum mode is configured as profile 0 - 4 QPSK, what will happend if i increase it?

Can you please send the PTP 820S Technical Description to chech all the tables?

I will send the link planner file to the mail that you sent to be check by Cambium.

Thank you very much