Thank you so much for the web page on the properties of waves. I work in communications, where we use simulcast.( multiple transmitters@same freq ). It so clearly can be used to illustrate the principles that plague us- beating, phase nulling and phase shifting are all phenomena so easily viewed in real time...It was great. I was searching for formulas to predict and regulate beat rate and ran into your site, and sure am glad I did. We will be employing offsets to our transmitters, as null durations can last ( and corrupt/miss ) several bits at a 2Hz mismatch between transmitters. The nulls must be regulated to work in conjunction with bit interleaving error correction schemes, hence my searches on the subject. Again, fantastic educational work. Thank you ! Ed Domas edomas@ucom.com