Neal,

As you note. And, just to tidy up loose ends, it should be noted that the GPS L1 (1575.42 MHz) is very nearly the 13th harmonic of the 121.5 MHz continuous analog homing signal, adding to the potential for interference and the difficulty in designing a GPS receiver that will adequately filter out this relatively very powerful signal immediately adjacent to the GPS antenna so that the GPS signal can be received and will not be overpowered. The manufacturers use various means to accommodate this issue, including shutting down the 121.5 for brief periods, but simply moving the GPS receiver away a small distance can make a big difference. The bottom line, in this instance, is that the user has a choice, whereas prior to this product, it was external or integral, one or the other.