The required change is one tenth of one percent. This works out to 4500 Hz, which could affect different sets in different ways
1) how sharp are the audio traps
2) does the set have split sound (in which case the user could tune to center the audio IF frequency), or intercarrier sound (factory tuned to 4.5000... MHz)
4500 Hz is a significant portion of the full sound carrier deviation (+/- 25 kHz), so intercarrier sets could experience increased distortion. The tight tolerance on the broadcast signal was meant to allow all the variations in tuning to be in the receiver for reasons of economy.
|