[Elecraft] K3: KPA100 Squeal

[Geoff Wolf AB3LS]

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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