Re: LF: Re: WRC-12 Approves the New 472-479 kHz Amateur Radio Allocation

["Clemens Paul" <cpaul@gmx.net>]

Greetings all,

I wonder what "secondary user on non-interference basis" means in 
practice.
As we know most NDBs are AM modulated with about 1kHz.
Now it would be interesting to know what selectivity/bandwidth DF 
receivers
for NDBs in aeroplanes might have.
Imagine they have 1kHz or even 2kHz (quite possible).
For non interfering such a receiver one would have to stay well 
without that
BW.
Hence with a few NDBs spread between 422 and 479kHz there would
virtually remain no usable frequency for us amateurs if we wanted to 
make
100% sure not to interfere any aeroplanes' beacon reception.

73
Clemens
DL4RAJ