Thanks. This sounds better than pushing the Q on the higher bands. I'll look
into it. Maybe it is better described in earlier editions of the handbook. I
have at least one from each decade, so I'll go back and do some reading!
Sent from my iPad
On 11 dec 2010, at 21:15, "Bill, W6WRT" <dezrat1242@yahoo.com> wrote:
> ORIGINAL MESSAGE:
>
> On Sat, 11 Dec 2010 19:26:16 +0100, "Ulf (SM0NOR)" <ulf@sm0nor.com>
> wrote:
>
>> This makes me think of a third solution mentioned in the handbooks
>
> REPLY:
>
> There is a fourth solution that is easier than all the others put
> together. It is disappears in depth in any of the ARRL Handbooks of
> recent years. I have used it myself on a six meter amp and it works like
> a charm.
>
> You create a simple L-network in the plate circuit by adding a small
> coil, typically about .5 uH or so directly from the tube's plate
> connector to the rest of the circuit. The coil together with the tube's
> internal plate to grid capacitance creates an L-network that steps the
> tubes native plate impedance down to a value which the otherwise large
> tune cap can handle with reasonable Q.
>
> It sounds like black magic but it works. Get an ARRL handbook if you
> don't already have one and look it over. It's in the chapter on
> amplifier design. The best part of the design is its effect disappears
> as you go lower in frequency and it has almost no effect on the lower
> bands.
>
> The best of all worlds.
>
> 73, Bill W6WRT
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|