K3 TX audio problem


Wojciech Tomczyk
 

A member of a local club bought a used K3  which  has a TX audio problem. In SSB mode transmitted signal band width is only 1.3 kHz and therefore very difficult to understand.  He tried several microphones but the problem still exists.
Various equalizer settings do not make  TX signal any wider. He also tried a factory reset but the signal still remains 1.3 kHz wide.
Any suggestions how to resolve this problem?

Tom


Jim Brown
 

On 9/22/2022 2:35 AM, Wojciech Tomczyk via groups.io wrote:
A member of a local club bought a used K3  which  has a TX audio problem. In SSB mode transmitted signal band width is only 1.3 kHz and therefore very difficult to understand.  He tried several microphones but the problem still exists.
Various equalizer settings do not make  TX signal any wider. He also tried a factory reset but the signal still remains 1.3 kHz wide.
Any suggestions how to resolve this problem?
I strongly suspect he's transmitting through a narrow plug-in filter, either because the wrong filter is in the #1 position, or a menu setting. The stock filter in a K3 is 2.7 kHz 5-pole, and you transmit through it. An upgrade is a 2.8 kHz 8-pole. But plug-in roofing filters (to protect the DSP from overload) come in a wide variety of bandwidths, and 5-6 can be plugged in.

I strongly suggest that your friend download a copy of the manual from their website, pour a nice wine or single malt, and STUDY the manual to understand the radio.

73, Jim K9YC


Frank Krozel
 

Unfortunately, this is happening more and more, as people try to take accessories out of the radios and try to resell it quickly to make a buck

In the past I have found people that couldn’t figure out that they had a 100 W PA, extra filters, and extra accessories before they resold the radio


Sincerely,  Frank Krozel t: 1-630-924-1600 frank@...
BSEE,   AASEET,   FCC Lic.# PG-18-19178,   KG9H
Electronic Instrument Associates - Central, Inc. ...


On Sep 22, 2022, at 4:55 AM, Jim Brown <k9yc@...> wrote:

On 9/22/2022 2:35 AM, Wojciech Tomczyk via groups.io wrote:
A member of a local club bought a used K3  which  has a TX audio problem. In SSB mode transmitted signal band width is only 1.3 kHz and therefore very difficult to understand.  He tried several microphones but the problem still exists.
Various equalizer settings do not make  TX signal any wider. He also tried a factory reset but the signal still remains 1.3 kHz wide.
Any suggestions how to resolve this problem?

I strongly suspect he's transmitting through a narrow plug-in filter, either because the wrong filter is in the #1 position, or a menu setting. The stock filter in a K3 is 2.7 kHz 5-pole, and you transmit through it. An upgrade is a 2.8 kHz 8-pole. But plug-in roofing filters (to protect the DSP from overload) come in a wide variety of bandwidths, and 5-6 can be plugged in.

I strongly suggest that your friend download a copy of the manual from their website, pour a nice wine or single malt, and STUDY the manual to understand the radio.

73, Jim K9YC







WE6R
 

If you try the other sideband, and the audio sounds a lot better, then you don't have the offset correct on the transmit filter. (or totally the wrong filter for TX).
The 2.7 needs the offset, the 2.8 does not.
And it must be one of those that is setup as the TX for CW & SSB. Use the K3 Utility. Read the kit-build manual.

Yes on folks doing a lot of options swapping and getting it wrong.
If you are buying/selling options, get the installation manual and go over the parts list to make sure you have ALL the necessary items.
Keith WE6R Elecraft K3 / K4 Tech.


mike z
 

I read this a couple weeks ago, and had the same thing happen recently.
K9YC hit it on the nose.
Thank you   Mike n3PM