diff --git a/rinex/src/header.rs b/rinex/src/header.rs
index 1cf330381..63afc1f00 100644
--- a/rinex/src/header.rs
+++ b/rinex/src/header.rs
@@ -1613,8 +1613,11 @@ impl Header {
                     for (constell, observables) in &obs.codes {
                         let mut descriptor = String::new();
                         descriptor.push_str(&format!("{:x}{:5}", constell, observables.len()));
-                        for observable in observables {
-                            descriptor.push_str(&format!(" {}", observable));
+                        for (i, observable) in observables.iter().enumerate() {
+                            if (i % 13) == 0 && (i > 0) {
+                                descriptor.push_str(&format!("        ")); // TAB
+                            }
+                            descriptor.push_str(&format!(" {}", observable)); // TAB
                         }
                         writeln!(f, "{}", fmt_rinex(&descriptor, "SYS / # / OBS TYPES"))?;
                     }
diff --git a/rinex/src/lib.rs b/rinex/src/lib.rs
index d604f4e2d..1ce62f1d7 100644
--- a/rinex/src/lib.rs
+++ b/rinex/src/lib.rs
@@ -147,12 +147,8 @@ pub(crate) fn fmt_rinex(content: &str, marker: &str) -> String {
         for i in 0..nb_lines {
             let start_off = i * 60;
             let end_off = std::cmp::min(start_off + 60, content.len());
-            string.push_str(&format!(
-                "{:<padding$}{}",
-                &content[start_off..end_off],
-                marker,
-                padding = 60
-            ));
+            let chunk = &content[start_off..end_off];
+            string.push_str(&format!("{:<padding$}{}", chunk, marker, padding = 60));
             if i < nb_lines - 1 {
                 string.push('\n');
             }
@@ -3471,4 +3467,16 @@ mod test {
             }
         }
     }
+    #[test]
+    fn fmt_observables_v3() {
+        for (desc, expected) in [
+("R    9 C1C L1C S1C C2C C2P L2C L2P S2C S2P",
+"R    9 C1C L1C S1C C2C C2P L2C L2P S2C S2P                  SYS / # / OBS TYPES"),
+("G   18 C1C L1C S1C C2P C2W C2S C2L C2X L2P L2W L2S L2L L2X         S2P S2W S2S S2L S2X",
+"G   18 C1C L1C S1C C2P C2W C2S C2L C2X L2P L2W L2S L2L L2X  SYS / # / OBS TYPES
+       S2P S2W S2S S2L S2X                                  SYS / # / OBS TYPES"),
+        ] {
+            assert_eq!(fmt_rinex(desc, "SYS / # / OBS TYPES"), expected);
+        }
+    }
 }
diff --git a/rinex/src/tests/production.rs b/rinex/src/tests/production.rs
index a7c42b939..13dfdcc4c 100644
--- a/rinex/src/tests/production.rs
+++ b/rinex/src/tests/production.rs
@@ -4,7 +4,7 @@ mod test {
     use crate::*;
     use std::path::Path;
     fn testbench(path: &str) {
-        // parse this file
+        println!("running on \"{}\"", path);
         let rnx = Rinex::from_file(path).unwrap(); // already tested elsewhere
         let tmp_path = format!("test-{}.rnx", random_name(5));
         assert!(rnx.to_file(&tmp_path).is_ok()); // test writer
@@ -67,6 +67,16 @@ mod test {
     }
     #[test]
     #[cfg(feature = "flate2")]
+    fn meteo_v3() {
+        let folder = env!("CARGO_MANIFEST_DIR").to_owned() + "/../test_resources/MET/V3/";
+        for file in std::fs::read_dir(folder).unwrap() {
+            let fp = file.unwrap();
+            let fp = fp.path();
+            testbench(fp.to_str().unwrap());
+        }
+    }
+    #[test]
+    #[cfg(feature = "flate2")]
     fn meteo_v4() {
         let folder = env!("CARGO_MANIFEST_DIR").to_owned() + "/../test_resources/MET/V4/";
         for file in std::fs::read_dir(folder).unwrap() {
diff --git a/test_resources/MET/V3/.gitkeep b/test_resources/MET/V3/.gitkeep
deleted file mode 100644
index e69de29bb..000000000