Welcome to TRS
You will need the Transceiver that is located around the key cylinder in the steering column of the explorer, along with it's wiring to the PATS module above glove box.
And of course the wiring between PATS module and computer
You can just put a working PATS key from the explorer inside the transceivers ring, tape it in place and put module and transceiver/with key, out of the way under the dash.
1998 PATS works like this
Key is turned on
PATS module powers up and sends a Radio Frequency(RF) Burst out of the Transceiver around key cylinder
PATS key's RF ID Tag gets energy from that burst and it sends out its unique RF ID Tag number, so no batteries required for PATS keys
Transceiver picks up that Tag number and sends it to the PATS module(transceiver = transmitter/receiver)
Module has a list of up to 6 Tag numbers, and compares in coming number to that list
If it finds a match then PATS module sends a unique code to Computer that allows computer to start fuel pump and fuel injectors for starting, starter motor relay was also added but not sure in 1998 PATS
If there is no match then computer never gets the "OK" to start fuel system
The PATS Module and Computer are "Married" at the factory, so they are a set, this means there is not a simple OK or NO that can be by-passed in the computer, they have an RSA encryption for OK or NO that changes each time they are booted up, so even if a thief were to intercept an OK code it wouldn't be any good for next start up.
If computer or PATS module are changed Ford Dealer needs to remarry them
So if working PATS key is in the transceiver when 1993 Ranger key is turned on the PATS will read the Explorer key's PATS number and allow vehicle to start.
Google: pats transceiver images
PATS is ONLY used for startup, it is not used once engine is running
You can also send out computer to a programmer who can delete PATS so it isn't require for starting