diff --git a/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf b/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf
index f2478e9a18..3a816159f2 100644
--- a/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf
+++ b/ci-scripts/conf_files/gnb-du.sa.band1.52prb.usrpb210.conf
@@ -190,6 +190,8 @@ RUs = (
        local_rf       = "yes"
          nb_tx          = 1
          nb_rx          = 1
+         # The higher att for TX than RX is because we use a circulator (as for TDD),
+         # while we should use a duplexer in the FDD case. However, it uses the same setup.
          att_tx         = 20
          att_rx         = 0;
          bands          = [1];