[Elecraft] VCO Alignment on K2

[Jay Sissom]

Thank you both for your help.  I spread the turns on T5 out a little
more and now I get 6V for 4000khz.  It also decreases as I tune lower
frequencies in the 80/75m band.

I will continue the alignment process and see how it goes.

Thanks again for your help
73
Jay
KA9OKT

On 10/18/06, Don Wilhelm <w3fpr at earthlink.net> wrote:
> Jay,
>
> I assume you are rferring to the voltage measured at the left end of R30
> while the K2 is tuned to 4000 kHz - if the voltage does not decrease as you
> tune lower in the band, then let's start again because you have a greater
> problem than just a bit too much inductance or capacity.
>
> First thing to do is look at the schematic for the RF Board sheet 1 of 4,
> and identify the components shown in the area labeled VFO Range Selection.
> Check those components for the proper values, especially be certain the
> varactors are the correct type (the 1SV149 has a smaller body than the
> MV209) and oare correctly oriented.  Also check varactors D23, D24, D25 and
> D26).
>
> Do count the turns on T5 once again, being certain that you are counting the
> number of times the wire passes through the center of the core rather than
> counting around the outside.  If the number of turns are correct, spread the
> turns out (loosen the mounting hardware first) a bit and the voltage should
> go down - you did spread the turns out over 85% of the core like shown in
> the manual did you not?
>
> Actually, it is usually preferrable to set the voltage when tuned to 4000
> kHz a bit higher than 6 volts, in fact, I usually try for about 6.5 volts
> there as long as all the other band end points are well within the
> acceptable range.
>
> 73,
> Don W3FPR
>
>
> > -----Original Message-----
> >
> > Hello, I am to the point in my construction where I align the VCO.
> > Every measurement has been correct to this point.  Unfortunately, the
> > lowest voltage I can get on R30 is 6.1 volts.  I have checked that L30
> > and C72 are both correct.
> >
> > It says that T5 is incorrectly wound in the manual.  It looks to me
> > that both windings have the proper number of turns.  Does anyone have
> > any hints on getting this voltage a little lower?
> >
> > Thanks & 73
> > Jay
> > KA9OKT
> >
>
>