Its not always that the data matches up with the experience. I can show you plenty of speakers with perfectly flat frequency response curves that sound like complete crap. Read about some of the information that Sherwood has talked about in the collection of data and actual use of a product. At times many measurements just don't stack up to actual use.
I think your best bet is to decide what modes are important to you and where you're going to be contesting and the like and then figure out what it is that is going to be important to you. Personally I have a bad QRM problem in my area and don't have time to make a loop antenna so I just switch in narrow filters to try and help mitigate it. The NB in my K1 doesn't do all that great on the noise but it helps. When this noise is present I find myself often operating about about 250Hz. So I got that filter. During field day I like to operate SSB as well so I got the 1.8Khz filter. If you're going to be doing SSB contesting and you want a slight advantage the 1.8Khz filter should be on the list. Then of course I'm going to be getting the 2.8Khz filter. My two remaining slots remain to be chosen but I'll make that decision after spending a few months with the radio. If you want data such as you mention the best way to get it is to do it yourself. Then once you're done sell the filters you no longer want before publishing it! ;) j/k.... On Wed, 2008-04-02 at 08:27 +0200, Arie Kleingeld PA3A wrote: > 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 _______________________________________________ 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
