Since the NB occurs right before the existing Xtal filter, adding more filtering in the NB slot would increase the skirts of the filter, but it wouldn't do a whole lot more. In other rigs with 2 filters, they are at different IFs and have other stages between them. Having a 2nd filter earlier in the signal chain helps to protect the RX from out of band signals.
The K2 already does that by having the only filter be as early as possible. But, a cool option would be to have a narrow SSB filter that could go in that slot. That way you could configure your SSB adapter to have a wide Xtal filter for good sound and then add the narrow one for contests and tough band conditions without having to resort to the variable CW filter (which performs poorly at wide bandwidths). Of course, if you can live without your NB. I certainly can. - Keith N1AS - -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of N2TK, Tony Sent: Wednesday, November 08, 2006 10:32 AM To: [EMAIL PROTECTED]; elecraft@mailman.qth.net Subject: RE: [Elecraft] K2 Roofing Filter? Don, Wasn't there talk a while back about someone replacing the Noise Blanker with another crystal filter? If it was switchable, like switching in and out the Noise Blanker, would that add to the shape of the skirts in the present crystal filter? Not sure about making up for any loss in the added filter though. Maybe set up this added filter for CW (400-600HZ) ? I still haul the K2 down to WP2Z. 73, N2TK, Tony -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Don Wilhelm Sent: Wednesday, November 08, 2006 10:15 AM To: Joe-aa4nn; elecraft@mailman.qth.net Subject: RE: [Elecraft] K2 Roofing Filter? Joe, To generalize - 'roofing filter' would be placed right after the first mixer for best effectiveness to strip off extraneous mixing products. The K2 is a single conversion design and the IF filter is placed right after the first mixer (there is a post-mixer amp there for good dynamic range) - so it serves both as the IF filter and the 'roofing filter'. In other words, yes a roofing filter 'does not compute' for a single conversion design. 73, Don W3FPR > -----Original Message----- > > In view of this, and excuse me for not being an engineer in receiver > design, why is there not a roofing filter option for the K2. Is it > just not possible in a single conversion rig? > de Joe, aa4nn > _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
