>- one frequency had worked on everything it has been tested on
Perhaps it depends on the method of application but I do know from my tests, that from direct electrode application, other frequencies have faster, stronger effects than the 666 Hz frequency.
And our experiments with other frequencies showed that the 666hz worked the best. Rife's other two frequencies also worked, but were slower since they were off by one. Other frequencies we tried from the frequency lists really did not do much if anything so we stopped using them.
More importantly, we found that there was an actual basis behind the frequencies that Rife kept. They were not really random working for some things and not others. This is why he was narrowing down the frequencies he was using, not increasing them.