First bit of help

[Brian -2]

Hello all,

 

This is my first post here, although I was hoping I would be able to make it
all the way through the K2 build on my own.  

 

I just got K2 serial #5946 on the air this past weekend.  Most everything
seems to be working properly, I get more than 15 watts out on all bands
except 10 meter which is about 10.2 watts and I'm happy with that.  My
problems are as follows:

 

The first is I am off frequency by about .35 khz  (example: I check into a
75 meter net on 3987.5 and I have to tune to 3987.85) This seems like a lot
to me. Is this within specs?  Adjusting C22 has no effect on this.

 

Second is my receive is severely attenuated. I'm really not sure where to
start. I tried adjusting the AGC threshold.  I can not get the voltage on U2
pin 5 above 3.8 volts.  I adjusted R1 so I got a reading of 3.0 volts.
Reset my s-meter alignment and now the signal strength is closer to where it
should be, but I don't know if I have fixed the problem or am I just masking
it.  

 

Any help would be greatly appreciated.

 

Thanks,

 

Brian

N1WNC

K2# 5946

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[Don Wilhelm-3]

Brian,

You should be able to have a dial calibration accurate to within 20 Hz.
Adjusting C22 will not have any effect during normal K2 operation
because it is only used during the CAL PLL and CAL FIL procedures.  It
should be adjusted accurately before running those.

Check out my webpage at http://w3fpr.qrpradio.com for the K2 Dial
Calibration article to see how it can be done accurately.  There are
other references on the Elecraft website.

For the receive attenuation, I cannot tell anything certain with the
information you have provided.  It may just be filter alignment that is
causing the perception of attenuation, so do the Dial Calibration and
filter alignment with Spectrogram (or similar) before making any judgments.

The AGC Threshold adjustment will not go very far above 3.8 volts.
Start at the 3.8 volt point for initial use.  When optimizing the
receive performance, you may choose to reduce the value, but in no case
should the voltage be reduced below 3.65 volts or the S-meter cannot be
brought into line for a proper response.

73,
Don W3FPR

Brian wrote:

> Hello all,
>
>  
>
> This is my first post here, although I was hoping I would be able to make it
> all the way through the K2 build on my own.  
>
>  
>
> I just got K2 serial #5946 on the air this past weekend.  Most everything
> seems to be working properly, I get more than 15 watts out on all bands
> except 10 meter which is about 10.2 watts and I'm happy with that.  My
> problems are as follows:
>
>  
>
> The first is I am off frequency by about .35 khz  (example: I check into a
> 75 meter net on 3987.5 and I have to tune to 3987.85) This seems like a lot
> to me. Is this within specs?  Adjusting C22 has no effect on this.
>
>  
>
> Second is my receive is severely attenuated. I'm really not sure where to
> start. I tried adjusting the AGC threshold.  I can not get the voltage on U2
> pin 5 above 3.8 volts.  I adjusted R1 so I got a reading of 3.0 volts.
> Reset my s-meter alignment and now the signal strength is closer to where it
> should be, but I don't know if I have fixed the problem or am I just masking
> it.  
>
> Any help would be greatly appreciated.

> Thanks,
> Brian
  N1WNC
>
> K2# 5946
>
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