Ron D'Eau Claire wrote: > > One of the early Elecraft customers, Sverre Holm, LA3ZA, put > together a wonderful page of K2 mods with links to the various documents. > Check here for info about the KNB2: > > http://www.qslnet.de/member/la3za/K2/modAny.html#KNB2 >
on that page in the section about: ¤Increase time constants http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-10/msg00086.html http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-10/msg00086.html or here http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-08/msg00040.html http://www.ac6rm.net/mailarchive/html/elecraft-list/2000-08/msg00040.html are both 404 links the gist of it said: NB1: 10us ->70us NB2: 70us->500us or 1ms For electrical noise from motors, electrical fence etc Increase C11 & C12 G3LUB but I found no reference to values to change C11 &/or C12 to ??? after some digging I finally found the information here: http://www.qsl.net/ve3mcf/elecraft_reflect/KNB2_Mods.txt > Date: Wed, 04 Oct 2000 16:04:31 -0600 > From: Larry East <w1hue at ida.net> > Subject: [Elecraft] Noise Blanker Observations > > Thought I'd add my two (binary) bits worth to the NB discussion: > > I find that my NB is very effective on an annoying popping sound (mostly > on > 80M) that I suspect is caused by an electric fence in the area. NB1 > reduces > it considerably and NB2 removes it completely. I get similar results for > certain types of static crashes: NB1 is somewhat effective and NB2 is very > effective. However, neither seems to be too effective against electrical > noise from drill motors, etc. > > Back in August a couple of folks posted notes that they had increased C12 > on the NB board by a factor of 10 to 20 (thus increasing the blanking gate > width to around 1-2 milliseconds) and got much better blanking of > electrical noise. So I decided to give that a try. > > Increasing C12 to 0.1uF definitely resulted in better attenuation (with > NB2 > selected) of some types of electrical and atmospheric noise. However, it > resulted in a rather raspy sounding CW signals. Backing off to 0.047uF > worked just about as well on noise and did not produce any noticeable > effects on signals. > > As a result, I have made the following mod to my NB board: > > 1. Changed C11 from 0.001uF to 0.0068uF (using the original C12 cap) to > give an NB1 blanking pulse width of 65-70 us (instead of 10 us). > > 2. Changed C12 from 0.0068uF to 0.047uF to give an NB2 blanking pulse > width > of around 500 us (instead of 70 us). > > Seems to be a good overall compromise for the types of noise that I hear. > Your results may vary. > > 72/73, > Larry W1HUE/7 > the root page was this one: http://www.qsl.net/ve3mcf/elecraft_reflect/index.html#k2modas maybe the above info will save someone else some time searching for the info. ----- 73 & GB KA5OAI Sam Morgan -- View this message in context: http://n2.nabble.com/K2-noise-blanker-tp2406404p2412591.html Sent from the Elecraft mailing list archive at Nabble.com. ______________________________________________________________ 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
