[Elecraft] Help - K2 Higher Noise Level with X1 Selected

[VK1OO]

Don,

The effect happens when the antenna is disconnected as well as when 
connected.
And in SBB and CW

SSB Filter Widths
X1 = OP1
X2 = 2.4
X3 = 2.1
X4 = 1.8

CW Filter Widths
X1 = OP1
X2 = 0.7
X3 = 0.4
X4 = 0.1

I assume something is going wrong in the 4.915MHz Variable Bandwidth 
Crystal Filter.

Mike

On 03-Jun-12 5:44 AM, Don Wilhelm wrote:
> Mike,
>
> Yes, I would say that you have a significant difference there and it 
> indicates a problem of one nature or another.
> What mode?
> How did you set up the IF filters?  Use Spectrogram.  Look at my 
> website www.w3fpr.com article on K2 Dial Calibration - Part 3 deals 
> with the filter setup.
> The reason I suspect the filter is that the XFIL 1 is a wide filter, 
> and if you did not offset the passband from zero frequency you will 
> have the BFO energy appearing in the output and that will influence 
> the S-meter response.
>
> 73,
> Don W3FPR
>
> On 6/2/2012 3:31 PM, VK1OO wrote:
>> Don,
>>
>> Nice to hear from you again.
>> I had a similar thought from Jim, W4ATK.
>> I'm surprised the S-Meter is showing an additional 6 bars on X1. As 
>> I'm listening to a quiet frequency I am assuming that's all 
>> additional noise. Further that that is much more than seems justified 
>> by the relatively difference in bandwidth.
>>
>> I'm happy to simplify the question to, Why would the S Meter be 
>> showing that much difference?
>>
>> Mike
>> VK1OO
>>
>> On 03-Jun-12 1:16 AM, Don Wilhelm wrote:
>>> Mike,
>>>
>>> I can't tell from your post just how much increase in noise you are 
>>> hearing.
>>> There will be an increase in the total noise heard just because the 
>>> bandwidth is increased - you will hear the total noise in the 
>>> passband, and when the passband is widened, the total noise will 
>>> increase.
>>>
>>> OTOH, if the increase is extreme, that would indicate a problem.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 6/2/2012 6:02 AM, VK1OO wrote:
>>>> Hi,
>>>>
>>>> Another interesting problem with the K2.  I've noticed that when
>>>> switching between the KSB2 filters, X1-X4, that there seems to be more
>>>> background noise on X1. And there is a similar increase in S meter 
>>>> bars.
>>>> On a quiet frequency with X1 selected, the S meter shows S8; X2-X4 
>>>> show S2.
>>>> I'd certainly appreciate any suggestions about where to start
>>>> troubleshooting this one.
>>>>
>>>>
>>>
>>
>