"INTERVAL SIGNALS ONLINE" is a web site that links you to your short wave listening past - without the static.
With short wave broadcasts to North America by international broadcasters all but gone, there is no way to hear those "Interval Signals" that identified each station as it signed on and off the air.
The "Interval Signals" for BBC World Service, Deutsche Welle, NHK Japan, Radio Nederland, Radio New Zealand Int'l, Radio Australia Int'. .... and many more stations can be found on this site. The site is well organized and the audio quality is very good. So if you are interested n "Interval Signals" check out this site: http://www.intervalsignals.net/