John, Do you have the older or the newer crystals installed? The newer ones have a "-S" suffix. If yours have a "-20" suffix, they are older and should be replaced with the newer ones.
It is not a question of crystal matching - the crystals in a set are matched, but one of the crystal characteristics - mainly the motional inductance (Lm) parameter. 73, Don W3FPR On 4/25/2011 7:00 PM, John Magliacane wrote: > --- On Mon, 4/25/11, Wayne Burdick<[email protected]> wrote: > >> I started with textbook impedance ratios, then adjust the windings 1 turn at >> a time to find >> the optimal combination of power transfer and passband flatness. This can >> vary with crystal >> characteristics, circuit strays, etc. > Thanks, Wayne. > > When I built my K2/100 back in 2003, I changed the coupling capacitors in the > crystal ladder network according to KI6WX's 2.5 kHz bandwidth mod. I ran a > TX sweep, and found my 6 dB bandwidth was only around 2.1 kHz. I never > measured the bandwidth prior to this change, but I know the change made the > rig "sound wider", with less ripple in the passband. > > So, I'm looking for reasons that might explain why the bandwidth is so > narrow. According to what I've read, the crystals I received with the kit in > mid-2003 should have been matched well enough for the bandwidth mod to work. > This is what directed my attention elsewhere, such as the transformers > surrounding the ladder. > > However, I'm beginning to think the crystals I received were not matched well > enough to provide much beyond a 2 kHz bandwidth. > > If crystal matching is indeed the problem, are new crystal sets available to > match the calibration number (3.7 in my case) from earlier KSB2s, or will all > 14 crystals need to be changed so all filters have well matched center > frequencies? > > > 73, de John, KD2BD > K2/100 #3563 > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
