diff --git a/speedtest_worker.js b/speedtest_worker.js
index c91f506..5d518d1 100644
--- a/speedtest_worker.js
+++ b/speedtest_worker.js
@@ -523,7 +523,7 @@ function ulTest(done) {
 						xhr[i].send(req);
 					}
 				}.bind(this),
-				1
+				delay
 			);
 		}.bind(this);
 		// open streams