[Elecraft] K3: KPA100 Squeal

[Geoff Wolf AB3LS]

Forgot to mention,

That recording was made using QSK CW in the TX Test mode.

AB3LS

On Thu, Jun 30, 2011 at 8:12 AM, Geoff Wolf AB3LS
<liltechdude13 at gmail.com>wrote:

> I haven't had a chance to try to run the rig off a battery.
>
> However, I was able to record the sound using my iPhone.
>
> I have uploaded the audio file here:
> http://alien.liltechdude.com/files/Recordings/kpasqueal.mp3
>
> I made sure the fan power cables weren't touching the fans/each other.
>
> AB3LS
>
>
>
>
> On Mon, Jun 27, 2011 at 10:14 PM, Guy Olinger K2AV <olinger at bellsouth.net>wrote:
>
>> If you can do it, see if you still have the noise running off a
>> battery.   73, Guy.
>>
>> On Mon, Jun 27, 2011 at 8:37 PM, Adi Andrei <e.adi.andrei at gmail.com>
>> wrote:
>> > The fans are still but I still hear it. Almost like some switching PSU
>> > noise.
>> >
>> > Adi
>> > 2e0ttx
>> >
>> > On 27/06/2011 15:21, Guy Olinger K2AV wrote:
>> >>
>> >> Check to make sure that the cables routed in front of the fans are not
>> >> touching.  A light touch will result in a sound like that.  It will
>> >> change or go away with the fan speed.
>> >>
>> >> 73, Guy.
>> >>
>> >> On Mon, Jun 27, 2011 at 9:10 AM, Adi Andrei<e.adi.andrei at gmail.com>
>> >>  wrote:
>> >>>
>> >>> I have the same thing happening, similar series K3 (5k something) ,
>> also
>> >>> assembled in March.
>> >>>
>> >>> Adi
>> >>> 2E0TTX
>> >>>
>> >>>
>> >>> On 27/06/2011 13:38, Joe Harris wrote:
>> >>>>
>> >>>> I have very similar symptoms in my K3/100 (SN 5284) that I assembled
>> in
>> >>>> March. It makes the sound even if I am in TX test mode. Again, no
>> >>>> performance issues, just a slightly bothersome squeal / whine.
>> >>>>
>> >>>>
>> >>>>
>> >>>> On Sun, Jun 26, 2011 at 8:23 PM, Geoffrey
>> >>>> Wolf<liltechdude13 at gmail.com>wrote:
>> >>>>
>> >>>>> First off it was a great Field Day and my new K3 impressed me
>> extremely
>> >>>>> not
>> >>>>> only in performance but in it's functionality.
>> >>>>>
>> >>>>> To kick off Field Day I installed a new KPA100 into the K3. I did
>> all
>> >>>>> the
>> >>>>> necessary TX gain calibrations using a dummy load.
>> >>>>>
>> >>>>> One thing I noticed immediately was that I was hearing a very high
>> >>>>> pitched
>> >>>>> squeal coming from either the PA board or possibly the KIO3 (the
>> board
>> >>>>> the
>> >>>>> amp plugs into). The squeal seems to vary in frequency each time the
>> >>>>> transmitter keys up (can only hear it when the radio is in TX). The
>> >>>>> squeal
>> >>>>> is not very loud but its loud enough for me to hear it if I listen
>> >>>>> closely.
>> >>>>> It doesn't seem to be power related. The squeal is there even if the
>> >>>>> radio
>> >>>>> is in TX but no power going out (RF Pwr set to 0W). The closest
>> thing I
>> >>>>> can
>> >>>>> compare the sound to is perhaps a tiny leak in an air hose. Is this
>> >>>>> typical
>> >>>>> of a bad solder joint or something?
>> >>>>>
>> >>>>> This squeal only pertains to the new KPA100 installation. Before the
>> >>>>> amp
>> >>>>> was installed I didn't hear a thing.
>> >>>>>
>> >>>>> I should also note that nothing appears to be affecting performance.
>> >>>>> Puts
>> >>>>> out 100 watts no problem. Clean modulation, etc.
>> >>>>>
>> >>>>> --------------
>> >>>>> Geoffrey Wolf
>> >>>>> AB3LS (Amateur Radio Callsign)
>> >>>>> University of Pittsburgh '14
>> >>>>> grw20 at pitt.edu
>> >>>>> Liltechdude at me.com
>> >>>>>
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