On 5/19/2022 11:38 AM, Jim Brown wrote:
Combining the outputs of the two receivers to a single (mono) channel is
problematic, because the phase relationships at audio have a good chance
of cancelling.
I should add that when diversity reception is used with wireless
microphones for broadcasting, entertainment, and worship, the outputs of
the two receivers are "voted" for best signal to noise ratio, just as
multiple receive sites are voted in VHF/UHF repeater systems. When I
lived in Chicago, I was part of a team maintaining one of several such
2M systems. The transmitter was on a tall building in the Loop,
receivers were at opposite ends of the metro area.
Here in the Santa Cruz Mountains, there's a very innovative system with
6-8 sites (a variable because wildland fires have destroyed several
sites), each of which receives and transmits the voted combination. The
transmitters are synchronized; cancellation is minimized because the
mountainous terrain combines with inverse square law causes arrivals at
any RX location from multiple transmitters to be nearly equal.
http://www.wb6ece.org/technical-info.html
73, Jim K9YC
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