Tips for adding voltage op amp to equipment
As the objective appears to be detection at a distance, of a series of maxima, whether they be a sine wave or a pulse train, here is an alternative approach that might be simpler:


Use a comparator such as the LM111 or a more recent, improved version, to convert the hall-effect sensor waveform to a series of pulses, by setting the comparison threshold around midway of the voltage range of the input signal. 


The "Zero Crossing Detector" in the linked datasheet is indicative.

Use the output to directly drive a current loop to the receiving end, e.g. the LM111 can sink or source sufficient current to "drive lamps or relays, switching voltages up to 50V at currents as high as 50 mA" (from the datasheet). No drive transistors or MOSFETs needed!
Use just a resistor on this current loop, at the receiving end, to read the pulses back as voltage pulses.


This Current Loop is a robust, standard long distance signaling mechanism used in industrial systems, such as the 4-20mA and 10-50mA systems. From the WikiPEdia page, "Current loops can be used over moderately long distances (tens of kilometres), and can be interfaced with optically isolated links.". 

The current loop mechanism is less sensitive to interference than any comparable voltage transmission solution, and the single-IC sense-and-transmit solution described above is hard to beat.