See Elecraft KPAIO3MDKT modification
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On 1/12/2020 3:19 PM, Rob Sherwood wrote:
K3 fans. N0QO and I found the problem when monitoring a K3 using a Perseus direct sampling receiver as a spectrum analyzer.
The noise pedestal was inside the 2.7 kHz or 2.8 kHz roofing filter that is in the circuit on transmit. The skirts of the roofing filter make the noise fall off rather quickly. The fans have either 3 or 4 speeds, and the noise pedestal gets worse the faster the fans spin.
I don’t know that this is your problem, but I thought I would mention it since it isn’t a widely known issue
On Jan 12, 2020, at 12:29 PM, wb6bee <wb6bee@...> wrote:
Are you thinking KPA1500 fans (or K3s fans)