[Elecraft] K3: KPA100 Squeal

[Geoff Wolf AB3LS]

No go.

Hooked the radio up to a gel cel battery and we're still getting the 12Khz
junk coming from something and the clicking between TX and RX.

I made a longer recording of the 'junk' and posted it. Cycled between TX and
RX a few times using the manual TX button on the front. Then finished off
with a few dits and dahs. All while in TX Test mode.

http://alien.liltechdude.com/files/index.php?dir=Recordings/&file=kpa3squealrev2.mp3

Anyone from Elecraft have anything on this?

AB3LS

On Fri, Jul 1, 2011 at 1:24 AM, Geoff Wolf AB3LS <liltechdude13 at gmail.com>wrote:

> This is a brand new K3 that I assembled about a month ago. The Serial
> Number is 5517.
>
> I have been using an Astron SS-25A power supply with this which is indeed a
> switcher. I have a battery that I'll be hooking up to it to see if this is
> still a problem.
>
>
> On Thu, Jun 30, 2011 at 4:41 PM, Guy Olinger K2AV <olinger at bellsouth.net>wrote:
>
>> A repeated 12 kHz would be echoed all over the room and lose a lot of
>> it's pulse nature.  This continues to look suspiciously like crap from
>> a 12 volt switching power supply that is somehow finding something
>> mechanically resonant in the K3.
>>
>> Back to asking for 12 volts from a linear supply (transformer and 60
>> Hz rectifiers) or battery.
>>
>> Is this particular K3 serial # prior to the introduction of gold
>> plated pins for the KPAIO3 connection?
>>
>> 73, Guy.
>>
>> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <Chuck.Broadwell at gmail.com> wrote:
>> > I looked at the MP3 file using Goldwave.  It appears to me that the "12
>> KHz"
>> > component is present only during the tics, not continuously.
>> >
>> > The tic period is roughly 270 msec (I have no idea what the tic is of
>> > course).   I zoomed in to a single tic (see PDF of images at the link
>> > below).  It appears that each tic has a very distinct pattern seen in
>> the
>> > individual samples which I suspect is the 12 KHz energy.
>> >
>> > I have no idea what any of this means.
>> >
>> > 73,
>> >
>> > Chuck, W5UXH
>> > Las Cruces, NM
>> >
>> >
>> https://sites.google.com/site/k3lineoutrecordings/ab3ls-mp3-file-analysis
>> > Images and comments from Goldwave view of the MP3 file
>> >
>> >
>> > Guy, K2AV wrote:
>> >>
>> >> Hi Geoff, below...
>> >>
>> >> On Thu, Jun 30, 2011 at 9:24 AM, Geoff Wolf AB3LS
>> >> &lt;liltechdude13 at gmail.com&gt; wrote:
>> >>> And, for even more information, I analyzed the audio that I recorded
>> and
>> >>> the
>> >>> squeal is right around 12Khz. It peaks at -48dB (louder than the QSK
>> >>> relay
>> >>> clicking)
>> >>>
>> >>> http://imgur.com/V8o5t - image of the analysis
>> >>>
>> >>> AB3LS
>> >>
>> >> With your image I realize I had been making some assumptions.  I need
>> >> to fill in some details...
>> >>
>> >> Are you listening to the audio in earphones or are you hearing it in
>> >> the free air.  I had been assuming listening with your ears only in
>> >> free air to miscellaneous sound in the neighborhood of the K3.
>> >>
>> >
>> >
>> > --
>> > View this message in context:
>> http://elecraft.365791.n2.nabble.com/K3-KPA100-Squeal-tp6518460p6534295.html
>> > Sent from the Elecraft mailing list archive at Nabble.com.
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