[Elecraft] K3: KPA100 Squeal

[Guy Olinger K2AV]

That would be:  You get this while in TX Test Mode?

On Fri, Jul 1, 2011 at 12:17 PM, Guy Olinger K2AV <olinger at bellsouth.net> wrote:
> You get this while in TX mode?
>
> Do you have the top cover on or off for this?
>
> Guy
>
> On Fri, Jul 1, 2011 at 1:49 AM, Geoff Wolf AB3LS
> <liltechdude13 at gmail.com> wrote:
>> 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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>>>
>>>
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