All, Reading all info about the roofing filters... Many opinions but I still miss a few things here to decide on which roofing filters I'm going to buy.
I'm a guy who likes to see the figures. (In the Lord we trust, others have to bring data...) Here's an idea. The following measurements for IMD would be nice. - Determine the dynamic range at 10 kHz with the 2.7 roofing filter switched in. - Decrease signal levels by 3 dB or 6 dB or so (that's up to the person that is measuring). The IMD-signal will then be well gone. - Then decrease the spacing of the signal frequencies until the IMD signals comes up again and write down the new spacing. - Put in more narrow roofing filter and decrease the spacing of the signals. - Determine at what new spacing the Intermod comes up. - Etc, do this for all roffing filters. So we get the following table as an exampe: Filter spacing (kHz) dynamic range 2700 10 103 dB 2700 3.2 97 dB (measuring the 103-6 = 97dB dynamic range spacing) 2100 2.4 97 dB 1800 2.0 97 dB Etc... Etc... So lets measure the spacing of the signals for a 97dB dynamic range instead of the other way around. If you really want to do this right, take several roofing filters of the same width and take several K3's. Cut the salestalk, bring me dataaaaaaaa..... It will sur help me out. Thanks in advance. Arie PA3A _______________________________________________ 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
