[Elecraft] AC hum on tune

[Guy Olinger K2AV]

Sometimes hum will be induced from transformers in the vicinity.  Run
the K3 on a card table by itself and see if the hum follows you.

73, Guy.

On Sun, May 16, 2010 at 12:16 PM, Karl Marderian <karlmar at sbcglobal.net> wrote:
> Bad power supplies, check for hum from them. Ground radio and/or power
> supplies. The A/C hum has to come from the wall supply.
> That's my two cents, good luck.
> N6XVT 73
>
> Sent from my iPhone
>
> On May 16, 2010, at 8:43 AM, Sam Morgan <k5oai.sam at gmail.com> wrote:
>
>> This one is a bit hard to describe, so please bare with me.
>>
>> I was talking to some locals (1-5 miles) this morning on 80m LSB.
>> I was told that when I was tuning up a hum was heard on my signal
>> by the guys, which were in LSB on their receivers
>>
>> I tried with low power 1w
>> I tried with higher power 90w
>> I tried it through the external amp
>> I tried it with the external amp off
>> I tried it direct to the antenna
>> I unplugged everything from the K3 but the power and antenna
>> I have switched power supplies,
>> I have switched AC outlets in the room.
>>
>> They say they still hear the hum.
>>
>> I switched to cw and
>> when they were still listening in LSB,
>> they still heard the hum on my cw signal.
>>
>> IF they switch to cw on their rigs,
>> they do NOT hear any hum on my cw signals.
>>
>> what in the world is going on here?
>> do I have a problem or not?
>> --
>> GB & 73
>> K5OAI
>> Sam Morgan
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