quote from you on the other site
31.4 + .455 - 4.890 = 26.965
31.4 being the crystal, .455 the IF and 4.890 being the vfo.
So since I still do not get this, what should I see between C14 and C22. that is part that really gets me atm.
ok using the above example for channel one,
lets start at the 31.4Mhz crystal oscillator, and the VFO, and how they are mixed,
the signal from the 31.4Mhz crystal oscillator and the signal from the VFO are being mixed passively at the junction of C14 and C22, at that point there is a total of 4 signals present all at once, the two fundamentals which are:
1: the 31.4Mhz crystal oscillator signal,
2: the 4.89Mhz VFO signal,
and two heterodyne frequencies which are:
3: the sum heterodyne at 31.4 + 4.89 = 36.29Mhz
4: the difference heterodyne at 31.4 - 4.89 = 26.51Mhz
now these heterodyne signals at this point are kind of like phantoms, and they don't really exist yet as distinguishable signals that can be seen on a scope or frequency counter, (i bet they would show up on a spectrum analyser though), but that will soon change after the signals passed through the 1st mixer, which is really not acting as a mixer in the conventional sense at all (because both fundamental signals are going into only one input), but is simply acting as an amplifier with a low Q or wide band tuned circuit on its output which is tuned to allow only the deference heterodyne frequency range to pass, therefore both the fundamental frequencies and the sum heterodyne are prevented from passing, and because of the flywheel or ringing effect of the tuned circuit at the output, what comes out is a real signal at the deference heterodyne frequency of the two fundamentals, which is 26.51Mhz,
now lets assume that there is a strong 26.965Mhz signal being injected into the antenna jack,
this 26.51Mhz signal from the 1st mixer is then mixed at the grid of the 2nd mixer with the incoming 26.965Mhz signal, and again two heterodyne frequencies are produced from those two fundamentals same as before, so we have two fundamental frequencies and two heterodyne frequencies at the input of the second mixer, and again at the output of the second mixer is another tuned circuit, this time a very hi Q or narrow band one, which is tuned to allow only the deference frequency of 455Khz to pass,
so here is the math:
31.4 - 4.89 = 26.51Mhz <--output from the 1st mixer
then
26.965 - 26.51 = .455Mhz or 455Khz <--output from the 2nd mixer
i hope that helped,