Thank you for the help. Despite owning the K2 since 2005 its not until now I start to understand it. :$ :-)
Thanks again and best 73 de SM0RVV ./Erik Den 30 apr 2012 13:04 skrev "Don Wilhelm" <[email protected]>: > Erik, > > Yes, that is why you cannot use a single signal (tone) when aligning the > filters. > The use of a broadband noise source and an audio spectrum analyzer > application running on the computer soundcard will make K2 filter setup > easy and uncomplicated. > > 73, > Don W3FPR > > On 4/30/2012 2:49 AM, Erik Linder wrote: > >> Aha! Then I did not fully understand the inner workings of the K2. >> I just looked att the schematics and noticed the BFO and the mixer. Out of >> that I made the conclution that the BFO value must change the pitch. >> >> So what you are saying is: >> During filter setup, it is normal for the pitch to change but when I press >> XFIL the save-routine inside the K2 is compensating for the change and >> restores the pitch to its original position? >> Is that correct? >> >> Which in practice means that I cannot adjust the pitch manually (like on >> an >> old radio), it's up to the K2 routine to set the pitch. >> >> ./Erik >> >> 2012/4/29 Don Wilhelm<[email protected]> >> >> Erik, >>> >>> The K2 will preserve the pitch when the BFO is changed. Of course, if >>> you move the BFO enough, the signal will no longer be inside the >>> passband. >>> >>> You must move the VFO to change the pitch, just changing the BFO will >>> not do it. The filter passband edges will change, but the pitch of a >>> tuned signal will not. That is why it is important to use a broadband >>> noise generator (often band noise will do) and some type of audio >>> spectrum analyzer (I use Spectrogram) to view the shape of the passband >>> - you can see when it is centered at your target pitch. Use no signals >>> in the passband when changing the filters, having signals present will >>> only confuse your view of the passband shape and positioning. >>> >>> If you need Spectrogram, you can find it on my website www.w3fpr.com - >>> look near the bottom of the opening page. >>> >>> 73, >>> Don W3FPR >>> >>> >>> On 4/29/2012 4:40 PM, Erik Linder wrote: >>> >>>> Don, tnx for the answer. >>>> >>>> Yes, the difference was small. Tnx for the info about 20 Hz, then I now >>>> >>> the >>> >>>> limitation of the construction. >>>> >>>> Yes I can use the FL1 (open) as both TX and RX (well of course TX is >>>> >>> alway >>> >>>> using FL1). But if I want something more narrow I like to use FL2 - FL4. >>>> And now I know that I can get in 20 or so Hz if I work hard enough. :-) >>>> >>>> But the main problem here is that I cannot adjust my filters at all >>>> right >>>> now. :-( >>>> I can move the BFO (change the pitch) as long as I am in cal fil but as >>>> soon as I save the filter and return to listen the pitch has changed to >>>> "default". The BFO-value _has_ changed, it _has_ been saved. (I see the >>>> display showing BFO freq for a short time). >>>> But still - the pitch is where it was before I changed the BFO-value. >>>> >>>> And I have changed it much - like 50 to 100 units. USB, LSB, CW - the >>>> >>> mode >>> >>>> does no difference. >>>> >>>> So: >>>> Received pitch of the signal transmitted from my 2:nd TRX: 1500 Hz >>>> The BFO value is (lets say) 128 >>>> I change the BFO value too 100 >>>> I hear (and see on the waterfall) that the pitch is changing. >>>> I press XFIL (to save) >>>> Display shows BFO freq for a short time. >>>> I press XFIL a couple of times to "get round" to FL1 again. >>>> The pitch has now jumped back to 1500 >>>> The BFO-value is at it's saved 100 >>>> >>>> I can now lower the BFO value once more and when I come around the pitch >>>> will be 1500 and the BFO is saved with the new value. >>>> >>>> Isn't it suppose to work like: >>>> Change the BFO to get the correct pitch >>>> Save >>>> Return to the filter and the pitch is where you programmed it to be. >>>> >>>> ______________________________**______________________________**__ >>> Elecraft mailing list >>> Home: >>> http://mailman.qth.net/**mailman/listinfo/elecraft<http://mailman.qth.net/mailman/listinfo/elecraft> >>> Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm> >>> Post: mailto:[email protected].**net <[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<http://mailman.qth.net/mailman/listinfo/elecraft> >> Help: http://mailman.qth.net/mmfaq.**htm<http://mailman.qth.net/mmfaq.htm> >> Post: mailto:[email protected].**net <[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
