diff --git a/src/nf_modules/ucsc/main.nf b/src/nf_modules/ucsc/main.nf
index fefde3354f5687c30e98e49ebbdbad3ad811da1f..e88f35a2419d5f7271605adcbe43c454e2952758 100644
--- a/src/nf_modules/ucsc/main.nf
+++ b/src/nf_modules/ucsc/main.nf
@@ -52,7 +52,7 @@ process bigwig_to_wig {
 bigWigToBedGraph ${params.bigwig_to_wig} \
   ${bw} \
   ${bg.simpleName}.bg
-awk '{if(NR>1) {if(\$1!=lastChrom){printf("variableStep chrom=%s\\n",\$1);lastChrom=\$1;}print \$2,\$4}}' ${bw.simpleName}.bg > ${bw.simpleName}.wig
+awk '{if(NR>1) {if(\$1!=lastChrom){printf("variableStep chrom=%s span=1\\n",\$1);lastChrom=\$1;}print \$2,\$4}}' ${bw.simpleName}.bg > ${bw.simpleName}.wig
 """
 }
 
@@ -77,10 +77,10 @@ process bigwig2_to_wig2 {
 bigWigToBedGraph ${params.bigwig_to_wig} \
   ${bw_a} \
   ${bw_a.simpleName}.bg
-awk '{if(NR>1) {if(\$1!=lastChrom){printf("variableStep chrom=%s\\n",\$1);lastChrom=\$1;}print \$2,\$4}}' ${bw_a.simpleName}.bg > ${bw_a.simpleName}.wig
+awk '{if(NR>1) {if(\$1!=lastChrom){printf("variableStep chrom=%s span=1\\n",\$1);lastChrom=\$1;}print \$2,\$4}}' ${bw_a.simpleName}.bg > ${bw_a.simpleName}.wig
 bigWigToBedGraph ${params.bigwig_to_wig} \
   ${bw_b} \
   ${bw_b.simpleName}.bg
-awk '{if(NR>1) {if(\$1!=lastChrom){printf("variableStep chrom=%s\\n",\$1);lastChrom=\$1;}print \$2,\$4}}' ${bw_b.simpleName}.bg > ${bw_b.simpleName}.wig
+awk '{if(NR>1) {if(\$1!=lastChrom){printf("variableStep chrom=%s span=1\\n",\$1);lastChrom=\$1;}print \$2,\$4}}' ${bw_b.simpleName}.bg > ${bw_b.simpleName}.wig
 """
 }
\ No newline at end of file