# 450 SM modulation

**URL:** <https://community.cambiumnetworks.com/t/450-sm-modulation/39136>\
**Category:** PMP\
**Created:** [December 5, 2014, 3:33am UTC](https://community.cambiumnetworks.com/t/450-sm-modulation/39136 "2014-12-05T03:33:22Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![CambiumMatt](https://d10gw3vjmzyp8.cloudfront.net/user_avatar/community.cambiumnetworks.com/cambiummatt/32/33533_2.png) [@CambiumMatt](https://community.cambiumnetworks.com/u/CambiumMatt)\
**Post date:** [December 6, 2014, 12:39pm UTC](https://community.cambiumnetworks.com/t/450-sm-modulation/39136/3 "2014-12-06T12:39:57Z")

</div>

Yes Nathan, I will agree with Rylan... that's about the healthiest link you can have.

Unfortunately, the way the modulation breakdown is reported is a bit confusing. When a fragment is received in 256-QAM modulation, it is&nbsp;_also_ counted in the lower modulations. This has to do with how OFDM technology works, and the constellation diagram of the OFDM signal.

To give a few examples, a perfect 8x link (i.e. a link that is able to achieve and maintain 256-QAM modulation) will report:

256-QAM: 25%

64-QAM: 25%

16-QAM: 25%

QPSK: 25%&nbsp;

just as you describe.

A link that cannot achieve 8x, but is a solid 6x link will show:

256-QAM: \<1%

64-QAM: 33%

16-QAM: 33%

QPSK: 33%

In real world deployments, it would be common to see something like:

256-QAM: \<1%

64-QAM: 14%

16-QAM: 42%

QPSK: 44%

which would indicate that the majority of the time, this link transmits at 4X (16-QAM), but sometimes is able to maintain 6X modulation... hope this explanation helps.

---

_[View the full topic](https://community.cambiumnetworks.com/t/450-sm-modulation/39136)._