[Elecraft] K2 Part II Alignment Probs

[Don Wilhelm]

Mark,

The BFO frequencies look OK, and the 3.7 marking on your crystals say that
the IF frequency should be close to
the center of 'normal' (=usual), so if you have inverted sidebands, we need
to look for something else awry.

Tune to 7000 and put the counter probe into TP1 and tell me what the
frequency reading is there (in CAL FCTR mode) - 11915 kHz is expected.

Sideband inversion can only happen if the mixer (or product detector)
frequencies are incorrect.  If your TP1 and TP2 frequencies are correct and
you still are receiving on the incorrect sideband, that would be a mystery
to me (the math says it has to be correct), so we would have to look at your
test setup - is it possible that you are driving a very strong signal into
the K2 and you are actually hearing both sidebands?  If you hear both, then
either your filter is not working properly or your signal input is so strong
it is overloading the receiver, or maybe something else, but this situation
is not normal.

73,
Don W3FPR

> -----Original Message-----
>
> > If you indeed do have inverted sidebands, then re-check the BFO
> range test
> > and let us know what the high and low BFO frequencies are. and
> let us know
> > the number (x.x) that was marked on the envelope your crystals
> were packaged
> > in.
>
> Doing the BFO Test from page 62:
>
> BFO high freq 4916.20
> BFO low freq 4911.09
>
>
> BFO freqs measured at TP2.
>                          band+       band-
> FL1  4913.61   4916.21     4911.01
> FL2  4913.22   4916.20     4911.09
> FL3  4913.22   4916.20     4911.09
> FL4  4913.11   4916.20     4911.09
>
> The first column of freqs is the BFO frequency before pressing the B+
> or the B- button. Note that C22 (the 4.000MHz calib) is not calibrated
> at this time.
>
> The crystal envelope had a 3.7 (three point seven) written on its front.
>
>