At 07:43 PM 5/6/2007 -0400, you wrote: >Hi Charles, > >Yeah I did, I've been using the 1 KHz filter for that, I'll try your >method and let you know how it works for me, thanks. >I find that most people don't really differentiate between 390's and >390A's especially if they don't own them, that's part of the reason why I >assumed Patrick meant a 390A, also in private correspondance he mentioned an A, > >Bob
Bob, The 1-KC bandwidth is too "tight" for AM work, in my opinion, It precludes being able to hear 2 and 3-kHz voice components which are very helpful...maybe essential, for intelligibility. ________ | 2 | | kHz | ________________| |__________ ----------------------------------- 1510 1520 1530 | | | | | 1521 Above is how I think you're tuning BKBSA-1521. The 2-kHz passband centers on 1521. As you can see, 1520 carriers are going to be audible as they are inside the passband. ________ | 2 | | kHz | ________________| |__________ ----------------------------------- 1510 1520 1530 | | | | | 1521 Above, you've "slid" the R-390As frequency up so that it reads something like "1522" on the dial. 1520 carriers are outside the passband. In slowly tuning across 1520 upwards, you should note that the 1521 het appears rather abruptly, As you continue to tune upward, the het should disappear abruptly. That's the sharp-sided shape factor of the R-390A mechanical filters working. The R-390 doesn't have that shape factor. As a matter of fact, the 1-kHz passband is shaped more like a sinewave. Only a crystal lattice filter replicates the shape factor of the mechanical filter. Cheers! Chaz-O Charles A Taylor, WD4INP Greenville, North Carolina _______________________________________________ IRCA mailing list IRCA@hard-core-dx.com http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: irca@hard-core-dx.com