CW Reverse Sideband Suppression Bad Using OP-1 Fixed

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

CW Reverse Sideband Suppression Bad Using OP-1 Fixed

W7is
 
Thanks for all the  suggestions on figuring out why I was hearing the other
side of zero  beat in CW Reverse on OP-1 filter.   The root cause of the
problem was  
I was using the BFO  freqs as specified in the KSB2 instruction manual.  
Which were never upgraded when they  changed to 2.5khz OP-1 filter.  
I corrected the BFO freq on CW Reverse to  match the USB BFO freq  
for OP-1 and now its  just fine.  Although with an S9  signal there is still
a tiny bit of  signal on the other side of zero beat using OP-1.  
I spent a lot of time the last two days  experimenting  
with different CW side  tone freqs.   I finally settled  on a sidetone of
400hz
due it had less  ringing while using  AF-2 narrow  band receive filter.  
On weak signal DX, its easier to  pick the signal out of the noise with the
audio filter set  to 400hz, at least for my ears.      
I  used CW filters of 2.5khz, 1.2khz, 700hz,  300hz.  Setting them
using the  Spectogram software and then did a final minor tweaking  by  
placing an audio freq  counter on the headphone jack and adjusted each filter
 
for 400hz receive tone  on both CW normal and CW reverse.  Then I fine tuned  
the SSB filters of  2.5,  2.2, 1.8 and 1.4khz  by  listening to a SSB receive
signal
while making  minor tweaking of Cal Fil BFO on each,  until the audio sounded
the best on each  filter.    That really  made this K2 come to life.  
Its a  real pleasure to  use.   Although it was a steep  learning process
trying
to figure it all  out. Thanks again for all the help from those on the forum.
 
Last week I built the XG-2  three band signal generator.  
XG-2 is one great piece of test  gear.  Highly  recommended.  
I also just finished  rebuilding and fine tuning a 1916 Vibroplex Model X
speed key.  
You can see the  picture of the key sitting in front of the K2 by looking up
my
call sign on  QRZ.COM    Frank   W7IS  

_______________________________________________
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

Reply | Threaded
Open this post in threaded view
|

Re: CW Reverse Sideband Suppression Bad Using OP-1 Fixed

Mike Harris-9
G'day,

| due it had less  ringing while using  AF-2 narrow  band receive filter.

There are alternate component values for the AF-2 filter to reduce the
ringing.  Developed by John Grebenkemper KI6WX

"Modifications to the KAF2 frequency response".  I'm not sure where I got
it from, it might be on the Elecraft web site.  It's only a 68KB pdf so I
could send it direct if you can't find it.

Regards,

Mike VP8NO


_______________________________________________
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