[Elecraft] [Bulk] Re Elecraft] Crackling in Headphones

[Guy Olinger K2AV]

"The crackling noises I hear in three different headsets occur with no
antenna connected. It does not occur all the time."

As you describe it, this does not sound normal, nor is it a common
trouble. The popping most refer to usually occurs with AGC off and
noise spikes with NB off. Yours sounds like a poor connection
somewhere.

You need to call Elecraft technical support with your problem. This is
far more likely to be something mechanical in the radio that needs
repair under warranty.

73, Guy K2AV

On Tue, Dec 1, 2015 at 2:11 PM, Jim Bolit <jbollit at outlook.com> wrote:
> The crackling noises I hear in three different headsets occur with no antenna connected.
>
> It does not occur all the time.
>
> I did not have this issue with my stock k3 which was sent in to Elecraft for the syn upgrades
>
> The crackling noise is very annoying when trying to do weak CW signal work.
>
> Jim
> W6AIM
>
>
>
> .
>
>
>
> -------- Original message --------
> From: "Joe Subich, W4TV" <lists at subich.com>
> Date: 12/1/2015 8:41 AM (GMT-08:00)
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] [Bulk] Re Elecraft] Crackling in Headphones
>
> On 12/1/2015 10:59 AM, Don Wilhelm wrote:
>> If there is an extra strong signal in the passband of the receiver,
>> having AGC on will reduce the strength of all signals within the
>> passband, but with the K3, all it takes is a turn of the width and
>> shift knobs to isolate the desired signal so that reduction in gain
>> due to the strong signal is no longer a problem.
>
> Provided the K3/K3S has a suitable selection of narrowed roofing
> filters available.  If one has only the single default 2.7 or 2.8
> KHz filter, it may not be possible to remove the strong interfering
> signal from the *input* to the ADC resulting in hardware AGC action
> and/or ADC overload which *can* create the crackling described.
>
> 73,
>
>     ... Joe, W4TV
>
>
> On 12/1/2015 10:59 AM, Don Wilhelm wrote:
>> Peter,
>>
>> I run digital modes with AGC on, I can't speak for anyone else.  The AGC
>> in the K3 can be customized (see my website www.w3fpr.com<http://www.w3fpr.com>).
>> "supposed to work better with AGC off" sounds like a generalized
>> statement.  If there is an extra strong signal in the passband of the
>> receiver, having AGC on will reduce the strength of all signals within
>> the passband, but with the K3, all it takes is a turn of the width and
>> shift knobs to isolate the desired signal so that reduction in gain due
>> to the strong signal is no longer a problem. There is no need to have a
>> full width waterfall when tuning to a specific signal.
>>
>> 73,
>> Don W3FPR
>>
>> On 12/1/2015 9:33 AM, Peter Pauly wrote:
>>> What about digital modes? I thought they were supposed to work better
>>> with AGC off?
>>>
>>> On Tue, Dec 1, 2015 at 9:30 AM, Don Wilhelm <w3fpr at embarqmail.com
>>> <mailto:w3fpr at embarqmail.com>> wrote:
>>>
>>>     For those with 'Crackling in Headphones', I have to ask if you are
>>>     running with AGC off?  If so, the limiter can be kicking in and
>>>     cause such crackling.
>>>     Better than running with AGC off, just leave the AGC on and if you
>>>     reduce the RF gain to counter strong signals, the AGC action will
>>>     be reduced.
>>>     I know old habits die hard, but the K3 is not the same as my old
>>>     NC-100 receiver and needs to be operated differently.
>>>
>>
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