Re: Azden dual system

$25 lavs can do a surprisingly fine job. But if you want something better, nobody's stopping you from buying a Sony ECM-44 and plugging it in to the transmitter.

Got to clear up something here, though:
Multiple frequencies is a good thing to avoid interference from other UHF sources, like church sound systems, police/fire radios, DTV stations, etc. However, having selectable freqs is NOT the same thing as having a diversity receiver.

A diversity receiver actually is TWO receivers, with separate antennas placed at slightly different locations. A comparator circuit constantly checks to see which receiver is getting the strongest signal, and uses that one.

What this does is to greatly reduce the chance of something called multipath distortion, or sometimes "RF dropout". The radio signal from the transmitter goes from the transmitter antenna to the receiver antenna...but it also goes in every other direction as well. The signal bounces off things that reflect RF, like steel beams, columns, chair frames, pipes...

These reflected signals ALSO arrive at the receiving antenna, but at slightly different times than the main signal. If the direct and reflected signals arrive out of phase, they tend to cancel each other out. This produces the aforementioned "RF dropout". It is this phenomenon that the diversity receiver was designed to counteract, since it's highly unlikely that signals will arrive at two separate antennas in such a way that the signal is cancelled out at BOTH locations simultaneously.

Regards,
Doug Graham