Sal, KD6VKW wrote:
"Wharever the reason, performance was worse, not better."

Sal, thank you for your U.S. Navy service.

My experience with diversity was different. At Radio Free Europe we
relayed broadcast programs by HF radio before communications satellites
existed.

We used Hammarlund SP-600 receivers in triple diversity. We found most
other receivers deficient. Our receiving sites were remote ffrom our
transmitting sites to avoid interference. We used UHF for short haul
relay.

For HF triple diversity each of the SP-600s was connected via an
isolation amplifier with a separate rhombic antenna aimed at its
transmitter. Outputs of the three receivers was fed into a Crosby or
Pioneer combiner which elected the best signal and rejected the other
two.

The horizontal rhombics each required four towers because they were
laterally spaced about ten wavelengths apart for space diversity at one
of the lower allocated frequencies. We, at times resorted to frequency
diversity too.

The receiver operator listened to both of the sidebands of each
transmitted frequemncy and selected the better of the two for reception
manually.

By selecting the cleanest frequencies and sidebands and using the output
combiners to select the instantaneously best of three signals, broadcast
quality programs usually prevailed.

Best regards, Richard Harrison, KB5WZI