diff --git a/README.md b/README.md
index fd86b6e..8a59e27 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,11 @@
 # adif-pota2sig
 
-Convert POTA fields in adif files to SIG and SIG_INFO fields
\ No newline at end of file
+Convert POTA fields in adif files to SIG and SIG_INFO fields
+
+Parse adif file, if a record has one or more POTA_REF entries (delimited by a
+comma), add SIG POTA and SIG_INFO with reference. Multiply record such, that
+every POTA_REF entry is a separate record with own SIG_INFO.
+Extended adif file will be printed to stdout.
+
+Usage:
+adif-pota2sig.pl logfile.adi > extended-logfile.adi
diff --git a/adif-pota2sig.pl b/adif-pota2sig.pl
new file mode 100755
index 0000000..c27baae
--- /dev/null
+++ b/adif-pota2sig.pl
@@ -0,0 +1,65 @@
+#!/usr/bin/env perl
+#
+# SPDX-License-Identifier: Beerware
+# Wolfgang DM5WK Kroener wrote this file. As long as you retain this notice you
+# can do whatever you want with this stuff. If we meet some day, and you think
+# this stuff is worth it, you can buy me a beer in return.
+#
+# modified from perlmonks - TedPride - http://www.perlmonks.org/?node_id=559222
+# modified from https://scruss.com/blog/2011/05/23/parsing-adif-with-perl/
+#
+# Description:
+# Parse adif file, if a contact has one or more POTA_REF entries (delimited by
+# a comma), add SIG POTA and SIG_INFO with reference. Multiply contact such,
+# that every POTA_REF entry is a separate contact with own SIG_INFO.
+# Extendet adif file will be printed to stdout.
+#
+# Usage:
+# adif-pota2sig.pl logfile.adi > new-logfile.adi
+
+use strict;
+use warnings;
+
+# use filename.adi as parameter
+open(my $FH, '<', $ARGV[0]) or die "$ARGV[0]: $!";
+
+while (<$FH>) {
+	print;
+	# fast forward past header
+	last if m/<EOH>\s+$/i;
+}
+
+my @entry = ();
+my @pota_refs = ();
+while (<$FH>) {
+	push @entry, $_;
+	if (m/<EOR>\s+$/i) {
+		# entry complete
+		if (scalar(@pota_refs) > 0) {
+			# add sig_info to each pota reference
+			foreach my $ref (@pota_refs) {
+				# print all except last
+				print @entry[0 .. $#entry - 1];
+				# insert POTA SIG
+				print "<SIG:4>POTA\n";
+				print "<SIG_INFO:" . length($ref) . ">" . $ref . "\n";
+				# print last
+				print $entry[-1];
+			}
+		} else {
+			# no park reference in this entry
+			print @entry;
+		}
+		# clear entry and pota refs for next entry
+		@entry = ();
+		@pota_refs = ();
+	} elsif (m/^<POTA_REF:/) {
+		# get last element of split >
+		my $val = (split(/>/))[-1];
+		chomp($val);
+		# fill pota_refs with references
+		@pota_refs = split(/,/, $val);
+		chomp @pota_refs;
+	}
+}
+close($FH);