Hi Benny, Thanks for your comments on the Pre-filter. I have put my comments in between yours.
73 Stewart G3RXQ On Sat, 19 Mar 2005 11:53:33 +0200, Benny Aumala wrote: > > > Installing prefilter IN STEAD of KNB2 gives the possibility to > place 5dB 140 ohm attenuator on the same board in front of the prefilter. > >> The Pre-filter has some loss, but if absolute MDS is not a criteria, then >> your idea may prevent some of the IMD performance being lost. >> > Then the 5dB pad should be temporarily taken out of function on main rf-board. > >> That needs to happen anyway when fitting the noise blanker. > Installing prefilter on top of KNB2 : >> Might cause a height problem for those fitting KPA100 in the K2 case. > -Input of KNB2 seems to have the necessary attenuation. > -Output can be taken from top of C6 and L2 and noise gate also > connected here through C8. This saves the step-up coil in xtal filter. > >> Yes, that might work. The terminations for the mixer are rather different >> between 5dB pad and noise blanker input. I don't know if Elecraft have >> published IMD figures with/without the noise blanker. > -Original 5dB pad off in main rf-board > -For removal, this KNB2 + prefilter unit must be replaced with a > simple board with that 5dB pad. > >> KE1L has a website with 'Un-modules' which allow various K2 modules >> to be removed while retaining signal paths etc. There is one for the KNB2 >> which would be ideal for those not having purchased a noise blanker. >> http://w5big.home.comcast.net/K2_Un-modules.htm > > Benny OH9NB > _______________________________________________ > Elecraft mailing list > Post to: [email protected] > 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: [email protected] 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
