Morning Sverre, OOOPS How stupid can I get. Of course you are 100% correct about VFO + BFO. Thank you for the information about the KPA100 modification. I fear that I am going to have to take a better look at the spurii here as some are quite intrusive, and some have changed since my last quick look in August 2004.
73, and thanks. Geoff GM4ESD ----- Original Message ----- From: "Sverre Holm" <[EMAIL PROTECTED]> To: "'Geoffrey Mackenzie-Kennedy'" <[EMAIL PROTECTED]> Cc: "'Elecraft Discussion List'" <elecraft@mailman.qth.net> Sent: Sunday, January 16, 2005 9:56 PM Subject: RE: [Elecraft] Birdie at10m: a choice between a turkey and an ostrich! > -----Original Message----- > >Agree with what you say, but I get a strong birdie at 28.276 without the > >KPA100 on. This one I think is LO + BFO , that is 23.361 + 4.915 = > 28.276, > >nominal freqs. Being first order it is also strong. Other products + mLO > +/- nBFO also >converge here, but are not a problem in my K2. > --------------- > > I cannot really explain this one without a 18432 oscillator in the K2. As > far as I can see the sum above is equal to the VFO + IF, so in that case it > would be valid for any frequency in the 15, 12, and 10 m bands? > > -------------------- > >There is no spur at 28.262 MHz with the KPA100 on as its crystal frequency > is 16,289 MHz >(later build?). But that oscillator might be contributing to > the other spurs. I have yet to > >sit down and do a worst case analysis. > -------------------- > > The 16289 is the oscillator frequency of the first run of KPA100's which was > later changed to 18432. The reason has been given as: > > "The modification kit also includes an 18.432 MHz replacement crystal for > use at X1. A new frequency was chosen to improve rejection of spurious > products, although the KPA100 was in compliance at the original frequency." > > Maybe this is concerned with spurious outputs from the transmitter? -and > probably someone on the list, beta-testers of the KPA100 perhaps, would > know? > > 16289, I believe is the oscillator frequency of the KIO2 and the KRC2 unless > they have been changed also. > > 73 > > Sverre > LA3ZA > http://www.qsl.net/la3za/ > > _______________________________________________ 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
