[Elecraft] TX Bandwidth

[Don Wilhelm]

David,

This is an often asked question - but it confuses the IF (or RF) 
bandwidth with the audio bandwidth.  You can only get 3 kHz of audio 
from a 6 kHz wide AM signal.  If you are using the 13kHz roofing filter 
for AM, you might get a bit more audio bandwidth.
It has been that way since the invention of AM modulation.  The audio is 
only 1/2 of the transmitted bandwidth.

An AM signal occupying 6 kHz of RF (IF) bandwidth will have audio only 
up to 3 kHz.  The AM signal transmits both sidebands, each containing 
the same audio information, so you can only recover half of that in the 
audio range.

The K3(S), KX3 and the KX2 report the audio bandwidth, not the IF (or 
RF) bandwidth.

73,
Don W3FPR

On 8/29/2016 5:13 PM, David Ahrendts wrote:
> Quick question: TX ESSB bandwidth is 4.0 kHz. Is AM bandwidth 6.0 kHz?
>
>