Meyers and Murdoch are discussing the radio signals they are receiving. Meyers says the frequency is so many "mhz". Murdoch says "that's megahertz". However the term hertz (for cycles/second) was not introduced until 1960. The correct earlier term would have been mc, megacycles or megacycles per second.
Murdoch says he needs two antennas to triangulate the signal. One antenna gives a bearing (straight line) and can be in front of and behind the receiver and can extend for a mile or more in either direction; two antennas give a cut (an "x") which narrows the transmitter's location to about a city block; three antennas give a fix (triangulate), which can pinpoint the transmitter to within a few houses. Murdoch needs a minimum of three receivers to triangulate the signal.
As Murdoch is working out the message coded in chemical symbols, in one of the shots it shows the symbol for Potassium as "Ka", but in two other shots it's abbreviated correctly as "K".