[ARC5] Re-reading Gordon White article...

[Ian Wilson]

I would guess that you want the mixer tank to resonate somewhere
around the geometric mean of the RF and the IF - so it can act as
load of reasonable reactance to the mixer plate without risk of
oscillation at either RF or IF. This is a pure guess, i.e. I have no
data to back this up :)

73, ian K3IMW



On Thu, Jun 6, 2013 at 12:28 PM, Kenneth G. Gordon <kgordon2006 at frontier.com
> wrote:

> I have been re-reading an article written by our own esteemed Gordon White
> for CQ
> magazine back in 1967 entitled "Command Set Receivers for All Frequencies
> - The Easy
> Way". In this article Gordon published data he got directly from ARC
> detailing the various coil
> and capacitor parameters to make receivers that cover from 190 Khz,
> through 40 MHz.
>
> One particular parameter I find to be both extremely interesting and
> completely puzzling, and
> I hope someone here can explain this to me.
>
> This is the resonant frequency of the RF amplifier plate coil, L-2, called
> the "mixer coil" in the
> data. The data is given as "...cold, with all tubes in place".
>
> For instance, for the 3 - 6 MHz receiver, that resonant frequency is 2200
> KHz. If one adds the
> IF frequency, 1415 KHz in this case, the result is 3.615 MHz.
>
> In every case, the resonant frequency of L-2 is way below the lowest
> frequency the receiver
> will tune.
>
> Anyone have a clue why this was done?
>
> I really don't understand.
>
> Ken W7EKB
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