diff --git a/src/TEF6686.cpp b/src/TEF6686.cpp
index fb4e36e..62b0d5a 100644
--- a/src/TEF6686.cpp
+++ b/src/TEF6686.cpp
@@ -665,12 +665,12 @@ void TEF6686::readRDS(bool showrdserrors)
 
                 if (offset > 4) {
                   if (((rds.rdsC >> 8) * 10 + 8750) == currentfreq) {                                                                   // Check if mapped frequency belongs to current frequency
-                    if (eon[position].mappedfreq = 0) {
+                    if (eon[position].mappedfreq == 0) {
                       eon[position].mappedfreq = ((rds.rdsC & 0xFF) * 10 + 8750);                                                       // Add mapped frequency to array
                     } else {
-                      if (eon[position].mappedfreq2 = 0) {
+                      if (eon[position].mappedfreq2 == 0) {
                         eon[position].mappedfreq2 = ((rds.rdsC & 0xFF) * 10 + 8750);
-                      } else if (eon[position].mappedfreq3 = 0) {
+                      } else if (eon[position].mappedfreq3 == 0) {
                         eon[position].mappedfreq3 = ((rds.rdsC & 0xFF) * 10 + 8750);
                       }
                     }