Jon Ogden wrote:
>
> >Band L
> >
> >80 13.6
> >40 6.5
> >20 1.75
> >15 1.0
> >10 0.8
> >
> >Now I have just created a spreadsheet for Pinetworks where I can vary
> >the tube impedance and the Q of the Pinet. I can't find a combination
> >where the L needed in the circuit matches what B&W provides. It is
> >certainly screwed up for my 41000A impedance of around 5000 Ohms.
>
> Ok, I did some more figuring. I decided that no law says that the value
> of Q has to stay fixed from band to band. So, I did some playing in the
> spreadsheet and found the following given the values of L above:
>
> Frequency Q C1 C2 L
> 
>
> 3.75 MHz 18 141.4 pF 1135 pF 13.7 nH
> 7.15 MHz 20 82 pF 691 pF 6.52 nH
> 14.2 MHz 38 78 pF 747 pF 1.776 nH
> 21.2 MHz 45 61.5 pF 597 pF 1.0 nH
> 28.3 MHz 42 43 pF 416 pF 0.8 nH
>
> So, I guess it is possible to use real world value components in this
> example, but the Qs get awfully high.
>
> I guess I am asking for some help here because it seems like the Q values
> get a bit high. Is this a good matching circuit design or not?
>
> 73,
>
> Jon
> KE9NA
Jon,
The inductance values you listed are better suited for a load
impedance of around 2500 ohms and a Q of 10 on the lower bands,
rising to around 18 on 10 meters.
73,Bob, W5AH

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