[Elecraft] K2 LSB Modulation issue

[Michael Jensen]

Hi Don 

Thanks for your answer. 

I have now done a realignment using Spectrogram as I did originally. I
believe using the exact same instruction.  

I might have asked this 4-5 years back but maybe without prober explanation,
any way I do not recall the answer. 

Setting the LSB FL4 for PSK to a bandwidth of 0.7 I struggle to reach a
center of 1KHz. I can get to about 800 with a BFO of 4912.99 and a dac of 16
going further then that the signal fade. Is that a problem....??

The tuned values for FL2 OPT1 are 4913.52 dac 001 and FL3 of 1.8 is 4912.94
dac 001...

I have not yet had the possibility for some one that know me to listen to my
tx audio, so I could tune FL1


For reference the setting on USB are FL2 OPT1 4916.36 dac 212, FL3 1.8
4915.90 dac 195 FL4 0.7 4915.08 dac 164


Thanks in advance 

73 de OZ1BZJ

Michael

 

-----Oprindelig meddelelse-----
Fra: Don Wilhelm [mailto:w3fpr at embarqmail.com] 
Sendt: 11. oktober 2010 00:49
Til: Michael Jensen
Cc: elecraft at mailman.qth.net
Emne: Re: [Elecraft] K2 LSB Modulation issue

  Michael,

I suspect that the BFO for LSB is not correctly for your KSB2 OP1 filter.
First check to be certain the SSB FL1 is set to OP1.  The BFO frequency 
for LSB using the OP1 filter will be between 4913.48 and 4913.65 
depending on your particular filter center, and the USB BFO will be in 
the vicinity of 4916.5.  You can check with the internal frequency 
counter probe in TP2, enter CAL FIL and tap the BAND- button.

Then go to my website www.w3fpr.com and read part 3 of the article 
dealing with K2 Dial Calibration - that is the section that explains the 
filter setting using Spectrogram.
If you do not have a copy of Spectrogram and or need information about 
how to set it up on your computer, download it from Tom Hammond's 
website www.n0ss.net.

If you have not set up your K2 filters before using Spectrogram, you may 
want to align all your filters.

73,
Don W3FPR


On 10/10/2010 5:36 PM, Michael Jensen wrote:
> Hi all
>
>
>
> I have noticed an issue on my trusty K2 #5111.  Might have been there
since
> I build it several years ago or it might have come during the years
>
> The issue are the modulation on LSB. The audio are not very good and do
> sound "funny" Could maybe be described as nasal or some one knowing my
voice
> call it "like the audio was being frequency modulated".
>
> USB are ok or at least so much better that no one notices.
>
> There are no difference between running high power or low power and have
> tested using different power supplies.
>
> The reason for going un detected is that I in the past not often was below
> 20 on SSB. When I used 40 or 80 it was mainly PSK but running USB. So no
> issue seen. When I was made aware of the issue I first put the blamed on a
> power supply for my PA as beeing the reason. (the magnetic field issue
> discussed here several years back). Now having tested for that it do not
> seem to be the problem.
>
> Any of you that would have experience or comments on a TX audio issue that
> effect only LSB.
>
>