[Elecraft] Loading Coils For Audio Transmission Lines

[Eric Swartz - WA6HHQ, Elecraft]

Folks,  we're drifting OT. Please wind this thread down and then take it to 
direct email if needed.

73,

Eric
List Moderator etc.
elecraft.com

On 3/31/2014 11:15 AM, Jim Brown wrote:
>
> Sorry George, but that's not quite right. The attenuation, velocity factor, 
> and characteristic impedance of ALL transmission lines vary drastically 
> through the audio spectrum. All transmission lines behave to some extent as a 
> low pass filter (because attenuation increases with frequency), and the 
> variation in Vf causes the higher frequencies to arrive before the lower 
> frequencies. Loading coils were added to phone lines to compensate for those 
> variations. The result was to "flatten" both the amplitude response and the 
> time response in the audio passband, then allow it to drop sharply above audio.