Filter Setup Questions

[k6dgw]

I'm setting up my K2/100 for RTTY, using a RigBlaster and MixW.  I
recently had an unrelated KPA100 problem, and Gary fixed it for me, and
also totally aligned the radio [thanks Gary, that service was totally
worth it, my K2 is way better than I thought, and I was pretty impressed
before!].  I don't want to change anything he did, it's really perfect,
except I want to adjust the BW of one of the SSB filters a little.  Can
I just adjust the BW in CAL FIL for that filter, and not mess with the
BFO settings?    I just want to make it a little wider and I really
don't want to undo what Gary did with everything else.

Second, are the USB and LSB filters locked together ... i.e. if I change
the BW on USB, have I also changed the BW on LSB?

Third, if my mark-space are normal below 15m, will they be inverted on
15m and above?

I just barely understand the K2 filter things, and sometimes I have QSB
in my mind.  This is one of those times.  (OK, maybe I don't
"understand" the K2 filter things like I said).

Fred K6DGW
Auburn CA CM98lw
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-3]

Fred,

If you change the width of a filter, you will likely have to change the BFOs
on both sidebands for that filter to keep the passband correct - you will
have to change the USB BFO as a minimum, the passband will shift more on USB
than on LSB just due to the shape of the filter.

If it is the OP1 filter width, forget about changing its width, that one is
fixed by the capacitors on the KSB2 board.  For the more narrow filter
widths, these are adjustable because they use the variable filter on the
base K2 RF Board.  When adjusting the passband position, use Spectrogram and
keep the low frequency corner of the passband at 300 Hz for best SSB
de-modulation, but if you are setting it for RTTY or computer soundcard use,
it can be positioned anywhere you want.

Yes, the USB and LSB filter widths are the same for any given filter
selection - no way to make them different.

The K2 takes care of the sideband inversion situation on the higher bands -
that is true for all filters, the RTTY set included.

If you want to set things up for RTTY, I strongly recommend that you set up
the RTTY filters if that has not already been done.  You will have a set of
filters that you can customize for use with digital modes, and it gives you
the ability to set the 'speech' compression to 1:1 independently of the
setting you use for SSB voice.

73,
Don W3FPR

> -----Original Message-----
>
> I'm setting up my K2/100 for RTTY, using a RigBlaster and MixW.  I
> recently had an unrelated KPA100 problem, and Gary fixed it for me, and
> also totally aligned the radio [thanks Gary, that service was totally
> worth it, my K2 is way better than I thought, and I was pretty impressed
> before!].  I don't want to change anything he did, it's really perfect,
> except I want to adjust the BW of one of the SSB filters a little.  Can
> I just adjust the BW in CAL FIL for that filter, and not mess with the
> BFO settings?    I just want to make it a little wider and I really
> don't want to undo what Gary did with everything else.
>
> Second, are the USB and LSB filters locked together ... i.e. if I change
> the BW on USB, have I also changed the BW on LSB?
>
> Third, if my mark-space are normal below 15m, will they be inverted on
> 15m and above?
>
> I just barely understand the K2 filter things, and sometimes I have QSB
> in my mind.  This is one of those times.  (OK, maybe I don't
> "understand" the K2 filter things like I said).
>
> Fred K6DGW
> Auburn CA CM98lw
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.430 / Virus Database: 268.15.6/567 - Release Date:
> 12/4/2006 7:18 AM
>

--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.430 / Virus Database: 268.15.6/567 - Release Date: 12/4/2006
7:18 AM

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com