For some RF Switch installations, isolation is an issue. Isolation is a measurement of the amount of signal appearing at unselected ports. For example, in an installation where a single transmitter is selecting between one of multiple antennas, most of the TX power will be routed to the selected antenna. Some small amount will be routed to the UNselected antennas. Typically, 30-40 db of isolation is provided by a single relay switch. This means that if 1000W is going to the selected antenna, less than 1W is going to the UNselected antennas. This is entirely adequate for this system design.
However, in some systems, there are MULTIPLE RADIOS and a switch selects one antenna to one of multiple radios. In this case, isolation is VERY important. A similar situation exists in Matrix Switches which can select multiple radios AND multiple antennas.
Using the prior example, if you radio is transmitting with 1000W, each of the UNselected radios would have 1W going into their receivers. This is an undesirable situation. For this case, very high isolation is desired. Even if the isolation prevents damage, the power of the Tx can still cause considerable interference to the other stations Rx, yielding it unsuitable for contesting. A transmitter of 1000W (+30dbm) with 50db of isolation would still result in a -20dbm signal into the Rx radio. This is a HUGE signal to a receiver with sensitivity of -110dbm. These numbers are used to show that popular and expensive RF switch on the market today provides totally inadequate isolation.
The Team-XCR 2:6 Matrix to be released soon, provides 80db of isolation at 14MHz. That is 1000x better than the competitor.