# 4.2.3 Protection ratio

This mode is identical to the “sensitivity” mode since the only difference is that the Blocking value (relative to the noise floor) is provided in dB. The software processes the information using exactly the same method to obtain the value of the receiver attenuation (see [A8.7](https://ecowiki.atlassian.net/wiki/spaces/SH/pages/492697 "https://ecowiki.atlassian.net/wiki/spaces/SH/pages/492697")).

The function *block<sub data-renderer-mark="true">Protection Ratio</sub>*(*Df*) that you entered represents the protection ratio, i.e. the ratio of maximum acceptable level of interfering signal to the wanted signal level, at a given frequency separation.

In this case SEAMCAT calculates the receiver attenuation *a<sub data-renderer-mark="true">VLR</sub>*(*Df*) to be applied to the interfering signal by using the following expression (see Figure 105):

*(Eq. 24)*

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/GZW81QnpOQGHceTW-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/GZW81QnpOQGHceTW-image.png)

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/7bMtDiIykGnBdjjZ-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/7bMtDiIykGnBdjjZ-image.png)

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/xR43Rds7Q0tzHqSr-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/xR43Rds7Q0tzHqSr-image.png)

[![image.png](https://wiki.cept.org/uploads/images/gallery/2026-04/scaled-1680-/n8ZFCYfy45LY4C7J-image.png)](https://wiki.cept.org/uploads/images/gallery/2026-04/n8ZFCYfy45LY4C7J-image.png)

<div class="rich-media-item mediaSingleView-content-wrap image-align-start css-1u5mjaf" data-layout="align-start" data-media-vc-wrapper="true" data-node-type="mediaSingle" data-renderer-start-pos="782" data-vc="media-single" data-width="236" data-width-type="pixel" id="bkmrk-figure-105%3A-mean-irs"><div class="css-uxysyr"><div data-alt="" data-collection="contentId-494086" data-context-id="494086" data-file-mime-type="image/png" data-file-name="image2016-8-8 11:0:36.png" data-file-size="21146" data-height="132" data-id="aabbda9a-ddef-4fb8-a579-902ac5eb2f21" data-node-type="media" data-renderer-start-pos="783" data-type="file" data-width="236"><div class="_2rko18qm _vchhusvi _kqswh2mm _ect4ttxp _p12f1osq _c71l1osq _1bsb1qmm _4t3ine4n _1hlmd0i9 _1rquusvi _eg541i5c _mts3kb7n _1ntskb7n _yfmhtlke _5sb1v00u new-file-experience-wrapper" data-media-vc-wrapper="true" data-testid="media-card-view" id="bkmrk-figure-105%3A-mean-irs-1"><div class="_1reo15vq _18m915vq _2rko18qm _1e0c1txw _kqswh2mm _p12f1osq _1bsb1osq _4t3i1osq _c71l1osq media-file-card-view" data-cursor="pointer" data-test-media-name="image2016-8-8 11:0:36.png" data-test-progress="1" data-test-source="remote" data-test-status="complete" data-testid="media-file-card-view"><div class="_kqswstnw _1bsb1osq _4t3i1osq _1e0c1txw _2lx21bp4 _1bah1h6o _4cvr1h6o align-center" data-testid="ImageRendererWrapper">![](blob:https://ecowiki.atlassian.net/d6adea82-baea-410b-8dff-220d62a225fa#media-blob-url=true&id=aabbda9a-ddef-4fb8-a579-902ac5eb2f21&collection=contentId-494086&contextId=494086&width=236&height=132&alt=&clientId=113268fe-fe5b-4bc3-8ff3-07965dbf1d18)**Figure 105: Mean iRSS<sub data-renderer-mark="true">blocking</sub> in case of Protection-ratio mode**</div></div></div></div></div></div>