[ARC5] 10 meter BC-454

[Kenneth G. Gordon]

On 7 Feb 2013 at 11:22, WA5CAB at cs.com wrote:

> Ken,
> 
> It does seem strange that the antenna coil tunes about right but the
> mixer coil doesn't.

I am thinking that tube interelectrode and stray capacitance makes it tune 
properly at the RF. I still haven't figured out the mixer grid circuit though.

>  Another strange thing that I just noticed is that
> the "typical" receiver photo in the RAT manual shows as best I can
> count either 6 or 7 rotor plates on the main tuning capacitor.  The
> plates are severely cut away (not much plate there) toward the outer
> (low frequency) end.  If someone had either of the two RAT or RAT-1
> receivers and could report what's actually under the hood on it/them,
> that might be beneficial.

Dave Stinson mentioned that he getting very curious and may look more 
closely at his 20 - 27 MHz RAT soon.

>  Likewise the number of turns in the coils.

Gordon White's article mentioned by John Rose does tell those. My coils 
follow those very closely....except for L-3. Mine has too few turns.....which is 
what I had calculated. The original had 6 1/8 turns, mine has 5, and I had 
calculated that it should have 7.

Ken W7EKB