What is the distance limitation on an IRIG-B connection?

Unfortunately, it is impossible to provide any specification on the maximum possible length of the connection since the IRIG-B port is actually a two wire unshielded cable and the transmitter strength may vary in different applications with different hardware. Hence, the maximum length is a factor of environment and arbiter transmitter strength, which best can be determined by trial and error.
An alternative solution to this can be the use of commercially available IRIG boosters. IRIG signals received by an ION meter has to be 5V nominal, however line losses may jeopardize this nominal voltage. IRIG boosters can be placed at a location where the signal fades in order to enhance the signal amplitude again.