Frequency Shift

[kd1na]

Hi All,

I am the owner of 2 K2s, one a K2-100 and the other a qrp model. I built one of the rigs myself but completely aligned both rigs.

My question.
What can I do to prevent slight frequency shifts when changing filter settings?
Both rigs exhibit this problem. The shift is only about 100 hz at the most but I don't think this should happen.

Other then the small shifting problem the rigs work perfectly.

I know there has been solutions posted on this forum in the past but I seem to not have the ability to search for them.

I am using the spectrograph program and following the procedure that accompanied it when downloaded.

I must be doing something wrong. It must not be the radios as both exhibit the frequency shift when changing filter bandwidths.
Any help or advise would be appreciated.

73
Dave KD1NA
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[Don Wilhelm-4]

Dave,

A BFO shift of up to 20 Hz is to be expected.
If you have 100 Hz shifts, then you need to run CAL PLL again - using
Spectrogram if possible.  Note that you should use a broadband noise
source or band noise (with the preamp on) with no signals present.  
Attempting to set the BFOs with a signal present in the passband will
result in frustration.

See my article on K2 Dial Calibration at my website www.qsl.net/w3fpr
for additional information.

73,
Don W3FPR

David Robertson wrote:

> Hi All,
>
> I am the owner of 2 K2s, one a K2-100 and the other a qrp model. I built one of the rigs myself but completely aligned both rigs.
>
> My question.
> What can I do to prevent slight frequency shifts when changing filter settings?
> Both rigs exhibit this problem. The shift is only about 100 hz at the most but I don't think this should happen.
>
> Other then the small shifting problem the rigs work perfectly.
>
> I know there has been solutions posted on this forum in the past but I seem to not have the ability to search for them.
>
> I am using the spectrograph program and following the procedure that accompanied it when downloaded.
>
> I must be doing something wrong. It must not be the radios as both exhibit the frequency shift when changing filter bandwidths.
> Any help or advise would be appreciated.
>
>  

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[Don Wilhelm-4]

Tom Hammond caught my 'too quick response'  I should have typed CAL FIL
below - not CAL PLL.

Sorry all and thanks to Tom for noticing.

73,
Don W3FPR

Don Wilhelm wrote:

> Dave,
>
> A BFO shift of up to 20 Hz is to be expected. If you have 100 Hz
> shifts, then you need to run CAL PLL again - using Spectrogram if
> possible.  Note that you should use a broadband noise source or band
> noise (with the preamp on) with no signals present.  Attempting to set
> the BFOs with a signal present in the passband will result in
> frustration.
>
> See my article on K2 Dial Calibration at my website www.qsl.net/w3fpr
> for additional information.
>
> 73,
> Don W3FPR
>
> David Robertson wrote:
>> Hi All,
>>
>> I am the owner of 2 K2s, one a K2-100 and the other a qrp model. I
>> built one of the rigs myself but completely aligned both rigs.
>>
>> My question.
>> What can I do to prevent slight frequency shifts when changing filter
>> settings?
>> Both rigs exhibit this problem. The shift is only about 100 hz at the
>> most but I don't think this should happen.
>>
>> Other then the small shifting problem the rigs work perfectly.
>>
>> I know there has been solutions posted on this forum in the past but
>> I seem to not have the ability to search for them.
>>
>> I am using the spectrograph program and following the procedure that
>> accompanied it when downloaded.
>>
>> I must be doing something wrong. It must not be the radios as both
>> exhibit the frequency shift when changing filter bandwidths.
>> Any help or advise would be appreciated.
>>
>>  
>

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