[Elecraft] Poor AM audio
Don Wilhelm
w3fpr at embarqmail.com
Sun Dec 30 11:11:43 EST 2012
Dave,
AM is a double sideband signal, so the audio you receive will be only
about half that of your filter setting. The 2.7 kHz roofing filter is
limiting the demodulated audio to about half the width of that filter -
1.35 kHz - so you will not hear any high audio frequencies no matter how
wide you set the DSP bandwidth. Even though the DSP bandwidth can be
set higher, the internals of the DSP currently impose a 4.2 kHz limit on
the audio response.
You will not be able to transmit AM until you install the 6 kHz filter
(or with the latest firmware the 13 kHz filter can be used).
In the meantime, for reception only, you can use the 2.7 kHz filter to
listen in synchronous AM mode.
73,
Don W3FPR
On 12/30/2012 9:42 AM, Dave Purola wrote:
> I just received and assembled my K3 about a week or so ago, I only have the 2.7Khz. filter that was shipped with the kit. I love the operation on SSB and digital modes BUT, when listening to the DX60 AM net the audio is quite distorted. I started out with the filter set to NORMAL and then made it as wide as possible untill the display reads 5.00. Is this normal to have the distorted audio untill I purchase the 6.00 Khz. filter? I quess I'm disapointed or am I doing something wrong? The operators manual does not say any thing about the distortion, only the fidelity will be increased with the 6.00 Khz. filter.
>
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