[Elecraft] CW for those with Poor Hearing

[Chuck Smallhouse]

Like Fred my hearing loss is associated to my military career, from 
standing near V2 and other large rocket firings at WSPG and a 4' 
lanyard firing of a 120 mm AA gun, to the firing of very adjacent 
155mm howitzers, and other very loud noises etc.

However when later doing very weak signal detection, while operating 
2M EME, I discovered, by accident and experience, that, good passive 
external sound prevention, could easily be obtained with just good 
headphone earmuffs.  Even an "old fashioned ringer" bell telephone, 
at my elbow, couldn't be heard.  I also found that my sweet spot 
audio frequency was about 400 Hz, with no ringing, even with an Autek 
1A external audio filter, cranked down to about 25 Hz BW.  The 
cheapest RS headphones (Nova 10), also had a mechanical resonance at 
about 400 Hz.   When all was aligned up at the 400 Hz sweet spot, the 
signal just seemed to jump out of the noise !  Easily 10 to 20 dB 
below the residual noise level, very comparable to what today is 
claimed by JT65 and other digital techniques .

Chuck,  W7CS