I did listen and look at my K3S on my SDR receiver in AM mode. I do find
there is a small amount of hum on the carrier. Then switching to LSB, I
do not find the hum present.
You may want to check the settings of your TX EQ. If you have any low
frequency boost, that will contribute to the level of the hum. My
operating values are: 50 Hz = -16 dB , 100 Hz = -16 dB , 200 Hz = -16 dB
, 400 Hz = -6 dB, everything above that is set to 0 dB or flat. The
mike is a Shure SM-58.
In AM mode the hum is noted at 120 Hz, 240 Hz, and 360 Hz, all multiples
of the 60 Hz line. At the same time, the hum level of the individual
frequencies, worst case, is some 40 dB below 100% modulation. Some are
50 dB below 100% modulation with the worst case being 120 Hz. In
working several AM stations over the past year or so, I've not had any
comments regarding hum on the carrier. These tests were done with MIC
level set to 0 and COM level set to 0. Everything else normal and
connected to the radio. Different power levels, mike level and comp
level made no difference in the amplitude of the hum components.
73
Bob, K4TAX
On 4/26/2019 10:43 AM, Nicklas Johnson wrote:
This morning just for yuks, I also temporarily disconnected the ground from
the rig entirely while also connecting only to a dummy load, so there could
be no path to ground at all, let alone multiple paths. No change.
I guess the next things I'll probably try are a full factory reset, and
then perhaps popping it open to make sure nothing has come unseated. But
first I'll drop a line to Elecraft support too. I've seen a number of
people post about similar problems that either magically resolved
themselves or ended up being a fault on the audio board.
Nick
On Thu, 25 Apr 2019 at 23:27, Nicklas Johnson <[email protected]> wrote:
Again, the problem persists with all inputs completely disconnected and
the mic gain set at 0. And running solely on a battery into a dummy load.
Nick
On Thu, Apr 25, 2019, 10:10 PM Jim Brown <[email protected]>
wrote:
On 4/25/2019 8:15 PM, Nicklas Johnson wrote:
Physically touching the case or grabbing the barrel of the front panel
mic
connector actually does cause the buzz to get just a little softer.
I suspect either a bonding problem or a problem with the wiring of the
mic.
I generally use solar/battery power, though my ground is bonded to my
utility ground.
I suggest that you carefully study either N0AX's recent ARRL book on
grounding and bonding, or the slides for talks I've given at Visalia and
Pacifion.
73, Jim K9YC
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