This has no doubt been covered here before, but is there a "shotgun"
equation or rule of thumb for this? (minimum Q for adequate flywheel effect)
In the past I've started with a pi input network with a Q of 4, (based
on an approximation of the tube operating parameters) but primarily
because that's about the highest I could use and get reasonable input
VSWR bandwidth on amateur bands. I'd like to accomodate "flywheel
effect", but haven't been able to find any reference so far beyond
cut-and-try.
I can see where using an autotuner (L network) would be a crapshoot,
since Q isn't part of the matching criteria and (generally speaking) the
algorithms basically cycle through the relay combos until a match is found.
So... With regard to my current YC156 project, I could summarize by
asking if with an assumed input impedance of around 25 ohms, (mostly
resistive) would a pi-net with a Q of 4 be an adequate flywheel?
BTW & OT:
I ended up ordering (2) guaranteed YC156 pulls from Tom, WA8WZG. Thanks
to all that offered the suggestion(s).
Thanks,
Jim N7CXI
On 10/7/2010 10:55 AM, Bill, W6WRT wrote:
> ORIGINAL MESSAGE:
>
> On Thu, 7 Oct 2010 07:40:50 -0700 (PDT), Lee Buller<k0wa@swbell.net>
> wrote:
>
>>
>> Have any of you used the method? Seems to have worked for the author of the
>> article in the Handbook.
>
> REPLY:
>
> The LDG autotuner does provide a good impedance match, but the only
> question is whether it provides sufficient Q to provide the "flywheel"
> effect needed for SSB operation. If you are going to be operating only
> CW, RTTY or FM, whatever Q it has is probably enough.
>
> I wish I had a more definitive answer.
>
> 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
|