I think that that comment was taken out of context. In his talk, I believe that he remarked that some xtals lacked quality control. I think it was said or implied that both the manufacturing process and testing process wasn't always perfect and that some xtals in the filters had some contamination or process defect that would cause them to have higher IMD products than they should. If that particular xtal was at the high signal end (input) of a ladder filter, it would produce IMD products. However, if it was at the other end of the filter, most of the strong signals would have been filtered out by that point and you would not see the problem. Since the filters were supposed to be symmetrical, theoretically it shouldn't matter which direction they were used. But given the lower quality of some of the individual xtals in the filter, he noticed the difference. That is what I got from his talk. I may not have interpreted it correctly. The K3 filters only plug in in one way, so if they were tested properly and the xtals manufactured properly, there shouldn't be any problems. Yes, the problem can still exist if the xtals are not manufactured properly.
On Wed, Mar 12, 2008 at 8:33 AM, K3KO <[EMAIL PROTECTED]> wrote: > > One thing stuck out. "Inserting filters in one direction in his testing > for > some rigs resulted in an 8db difference relative to the opposite direction > in a performance parameter." > > Are K3 filters properly polarized so this won't happen? Has the filter > technology improved so this isn't an issue? Or is it a crap shoot with a > 50/50 chance of getting it right even with polarized filters? > _______________________________________________ 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
