[bbulkow]

The only real question, imho, is why this wasn't understood when the frequency was auctioned. If we needed more guard band, we needed more guard band. If antennas point to the sky, don't use the close frequencies.

Any answers?

[houseofzeus]

The information provided at the time indicated 100 Mhz buffer would be enough, which the FCC doubled. Now the FAA are saying that in fact even 200+ Mhz buffer outside of the frequency that was ever allocated for this purpose is not enough for some altimeters.