[Elecraft] Experiment: how much PL tone deviation is required to reliably key repeaters?

[Jim Brown]

On Sat,9/6/2014 9:36 AM, Wayne Burdick wrote:
> There seems to be some debate about how much FM deviation is required for PL tones used to activate repeaters. There's a wide range of deviation values in use by transmitters, and various "standard" recommendations. The question is how much is needed for reliable operation in the real world.
I've always seen/heard 500 Hz deviation. The first link says 15% 
deviation. The second quotes a standard that says 12%, and quotes email 
from a reader saying that 12-14% provides the most reliable decoding 
under marginal conditions. Several references note (correctly) that when 
PL is heard it is nearly always the harmonics in a tone with distortion.

http://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System

http://www.repeater-builder.com/tech-info/ctcss/ctcss-overview.html

http://www.radagast.org/~dplatt/hamradio/FARS_presentation_on_modulation.pdf

http://www.metrocor.net/info/ctcss.htm

73, Jim K9YC