[Elecraft] K3: KPA100 Squeal

[Geoff Wolf AB3LS]

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



On Thu, Jun 30, 2011 at 8:17 AM, Geoff Wolf AB3LS
<liltechdude13 at gmail.com>wrote:

> 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
>>> >>>>>
>>> >>>>> ______________________________________________________________
>>> >>>>> Elecraft mailing list
>>> >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> >>>>> Help: http://mailman.qth.net/mmfaq.htm
>>> >>>>> Post: mailto:Elecraft at mailman.qth.net
>>> >>>>>
>>> >>>>> This list hosted by: http://www.qsl.net
>>> >>>>> Please help support this email list:
>>> http://www.qsl.net/donate.html
>>> >>>>>
>>> >>>>
>>> >>> ______________________________________________________________
>>> >>> Elecraft mailing list
>>> >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> >>> Help: http://mailman.qth.net/mmfaq.htm
>>> >>> Post: mailto:Elecraft at mailman.qth.net
>>> >>>
>>> >>> This list hosted by: http://www.qsl.net
>>> >>> Please help support this email list: http://www.qsl.net/donate.html
>>> >>>
>>> >
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:Elecraft at mailman.qth.net
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>>
>>
>>
>