automatic car aerial tester

e- The circuit entitled "automatic car aerial" as dof 10 automatic car aerial control scribed in the Summer Circuits 1977 issue Elektor has proved to be very popular. However, some readers were less than fully happy about the circuit because it did have a tendency in some instances to have one slight problem: namely, the two relays used to switch the aerial up and down tended to give a certain amount of contact bounce. It would be far better for this type of automatic system to have a precisely defined time limit for the "up" and "down" operations. This is very easy to obtain nowadays with modern integrated "monoflops. Two of these monostable R2 multivibrators are contained in the CD 4098 IC as aerial used here. One monoflop is used to "run the at pin up and is triggered by a positive-going pulse 12. The other one requires a negative-going trigger pulse at pin 5 when the aerial is to be run down. are first The control pulses from the car radio and C1 to "debounced" by components...