From 5a0878e0e56b01e4ca8a0b5c2161e1aecdba1e2e Mon Sep 17 00:00:00 2001
From: Sjef Verhoeven PE5PVB <pe5pvb@het-bar.net>
Date: Sat, 11 Nov 2023 12:23:37 +0100
Subject: [PATCH] RDS USA mode: When callsign not found in database and
 calculator ends up with wrong chars, only show a ?

---
 src/TEF6686.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/TEF6686.cpp b/src/TEF6686.cpp
index 0af34ed..b62bf78 100644
--- a/src/TEF6686.cpp
+++ b/src/TEF6686.cpp
@@ -540,6 +540,21 @@ void TEF6686::readRDS(byte showrdserrors)
               rds.stationID[3] = char(((stationID - 676 * int(stationID / 676)) % 26) + 65);
             }
           }
+
+          bool faultyID = false;
+
+          for (byte i = 0; i < 4; i++) {
+            if (!(rds.stationID[i] >= 'A' && rds.stationID[i] <= 'Z')) {
+              faultyID = true;
+              break;
+            }
+          }
+
+          if (faultyID) {
+            for (byte i = 0; i < 9; i++) {
+              rds.stationID[i] = ' ';
+            }
+          }
           rds.stationID[7] = '?';
           rds.stationID[8] = '\0';
         }