CW filter weirdness

[Chris Iwata]

Yes, what you say is all correct. If you had a true CW filter and the beat  
freq  was off, you'd maybe get a zero beat and tuning each side of the  zero 
would start fading at about 200Hz since the CW filter has around a  400Hz 
bandwidth. But, rather than having a wide open response, I would  think a defective 
filter would have virtually no response.  Only other  thing I can think of is 
there is spurious coupling between the input and output  of the filter, which 
in effect by-passes the filter.  Maybe the CW-LSB-USB  mode switch is wired 
wrong?  (I can't remember what the SB102 front  panel looked like, but as I 
recall my HW101 had such a switch.)
 
Chris
 
In a message dated 2/12/08 3:54:12 P.M. Pacific Standard Time, WD4SCZ  writes:

3 crystals are marked with the correct frequencies as is the crystal  filter 
supposedly, 3395.4 kHz  When receiving CW signals the receiver is  
automatically tuned 1 kHz below the transmit freq by crystal Y1 (3396.4  crystal)and tube 
V16A. In the transmit mode, tube V16B and the Y3 crystal  (3395.4) make the 
output the same as the incoming from the other station, at  least that's how I 
understand it.
 
I keep suspecting the CW filter is somehow screwy, no matter what it says  on 
the outside.  Switching the filter from SSB to CW won't make the "zero  beat" 
change as if one of the BFO crystals were off freq? Or am I still  missing 
something?

 
 

Either the center frequency of your filter is incorrect, or the BFO  crystal 
for CW is off frequency.  The center freq is usually stamped on  the filter.  
Check your manual to see what the BFO freq should  be.
 
Chris, KL7DM
 





 



**************The year's hottest artists on the red carpet at the Grammy 
Awards. Go to AOL Music.      
(http://music.aol.com/grammys?NCID=aolcmp00300000002565)

-----------------------------------------------------------
Products bought, sold or traded here is the responsibility of the
parties involved.  This list and the City of Tempe are not responsible
for losses or misrepresentations of any kind.  Buyer beware!

-----------------------------------------------------------
This list is a public service of the City of Tempe, Arizona
-----------------------------------------------------------

Subscription control - http://www.tempe.gov/lists/control.aspx?list=HEATH
To post - HEATH at LISTSERV.TEMPE.GOV
Archives - http://listserv.tempe.gov/archives/HEATH.html