I just added the pad capacitors to c174 and c173. It helped but not enough. The high freq. is now 4917.37 and low is 4913.92 for a range of 3.45 kHz. Is it possible to get new crystals from Elecraft if indeed I do have the ones with the higher Q?
Thanks > > From: "Don Wilhelm" <[EMAIL PROTECTED]> > Date: 2005/12/07 Wed PM 01:31:31 PST > To: <[EMAIL PROTECTED]>, <elecraft@mailman.qth.net> > Subject: RE: RE: [Elecraft] K2 BFO Test > > The preferred method of padding the BFO capacitors is to maintain the ratio > between C173 and C174 by paralleling them with capacitors. A single > capacitor from the junction to ground will be in parallel with the series > combination of C173 and the varactor D38 and could make the BFO less stable > than it should be. > > You are welcome to try the single capacitor solution, but do beware of the > pitfalls. If you would like further documentation on padding the BFO, > download the K2 AtoB instructions and look at the 2nd column of page 12. > > 73, > Don W3FPR > > > -----Original Message----- > > > > All the components look right. I guess I've got the dreaded high > > Q crystals. I've noticed in the Elecraft archives that it is > > possible to put a capacitor at the junction of X3/X4 to ground. > > Which is the preferred method? > > > > Thanks. > > > > > > From: "Don Wilhelm" <[EMAIL PROTECTED]> > > > Date: 2005/12/07 Wed AM 09:30:04 PST > > > To: <[EMAIL PROTECTED]>, > > > <elecraft@mailman.qth.net> > > > Subject: RE: [Elecraft] K2 BFO Test > > > > > > Ted, > > > > > > Yes, you should get the BFO range and frequency correct - you > > can continue > > > with no extra effort, but it must be resolved eventually, and > > there is no > > > time like the present to do it. > > > > > > Check the values of the capacitors C173 and C174, and while you > > are at it, > > > check C169 too. Additionally, check the varactors D37 and D38 for the > > > correct type (1SV149 - the smaller ones) qne proper > > orientation. Be certain > > > the BFO crystals were the ones you soldered in - they are > > typically marked > > > ECS D4.91 -S > > > > > > If you find all the above correct, you may have to pad > > Capacitors C173 and > > > 174. Should that become necessary, use 47 pf in parallel with > > C174 and 120 > > > pf in parallel with C173. The padder capacitors will lower the low > > > frequency end more than the high frequency end of the range, so > > it should > > > work for you - but do the padding only if there is nothing else > > wrong with > > > the components. > > > > > > 73, > > > Don W3FPR > > > > > _______________________________________________ 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
