During the classical period (roughly 1750-1820) a number of instruments fell more or less entirely out of favour, including recorders, lutes and viols. The harpsichord was replaced by the piano, and the guitar was generally heard less often than before.
78s had been phased out by the 1960s so it's very doubtful you'd have any from that decade or from the 1970s. Are you referring to LPs? If so, please post a new question so that others can help answer.
Yes, it is possible to use direction finder devices (usually radio receivers with directional Antennas abbreviated to "DF receivers"), the most common and oldest method is triangulation of the the two way radio signal by two and ideally three DF receiver stations, these will compare results and they will be able to locate a two way radio device quite accurately as long as it is transmitting reasonably continuously. At VHF & higher frequencies there are direction finders that use a special antenna array on top of vehicle and use methods to detect the Doppler effect by doing timing comparisons of the received two way signal by switching the receiver to different positioned and phased antennas and the results from the receiver detected pass through a signal processor which can process and and indicate the origin of a two way signal with reference to the DF receiver antenna array position and display it on a screen. Cell phones locations are detected in a similar way by using various cell sites and special processing Software to get an accurate fix on the cell phone position.
Incidents for which there is a warning period
a phase is a period of time when an event happened. 'phased' must mean that event has passed. it WAS a phase. as in this is going to be phased soon.
initial phase : to provide temporary power...
Bay Rum cologne was popular although had to be phased out during WW2.
phased manufacturing process
The French Franc was phased out during the year 2001 (The Euro was phased in at the same time) and put out of commercial use on Jan 1, 2002 (but coins and notes could still be changed in banks).
Horses have not been phased out, they are still as popular as they were years ago.
Freon-11 and Freon-12, both refrigerants, were banned in 1996.
The Canadian one dollar bill was phased out by the Canadian National Government in the year 1987. They were phased out in July of that year. They have not been used since then.
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Buffer solutions reduces the ionization during the elution in the column and gives a long life for Reverse phased columns.
This is slowing being phased out at the Bell Center in Montreal. Chances are that by the next hockey season, smoking during hockey intermissions will be a thing of the past.