[BC] FM Band other used for 19 kHz.

[DHultsman5@aol.com]

Ok  Brain trust  I have several questions.    What  can we technically use 
10% of the FM signal at 19 kHz.  for other than  light the stereo light (not 
primary) and phase locking the 38 kHz. DSSB  suppressed carrier?
 
I have heard several ideas in the past, Frequency shift keying for  data?  By 
adding a time constant to hold the receiver phase while the 19  kHz. is 
shifted + or -. 
 
I have heard discussion of amplititude modulating the 19 kHz. low response  
with no cut off below 2% modulation for telemetry tones.
 
Since it was such a small amount of bandwidth and % of  modulation.   Think 
about it.   It seems that we are wasting  10% modulation when the receivers 
could be locked with todays  technology.   
 
I doubt that it will ever be changed but  I wonder if you could do  something 
similiar to RBDS on the 19 kHz?
 
Think out of the box.......Comments and ideas???
 
Dave
 
hanging out in Pittsburgh