You should be able to pick up a 23rd edition on Amazon.com.
73
Jim W7RY
--------------------------------------------------
From: "Jim Barber" <audioguy@charter.net>
Sent: Thursday, October 07, 2010 12:34 PM
Cc: <amps@contesting.com>
Subject: Re: [Amps] Autotuner for Amp Input
> That works, thanks.
>
> Playing with the models shows that designs between 25 and 70 ohms
> cathode impedance meet the 13pf/meter criteria using a pi-net input with
> a Q of 4. Above 70 ohms not so much.
>
> If I ever find a copy of Orr's 23rd edition at a reasonable price I'll
> pick it up. I see quotes from it zip past here every now and then.
>
> 73,
> Jim N7CXI
>
>
> On 10/7/2010 11:58 AM, Gary Schafer wrote:
>> Bill Orr recommends around 13pf per meter for the capacitance at the
>> cathode
>> of a GG amplifier.
>>
>> 73
>> Gary K4FMX
>>
>>> -----Original Message-----
>>> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
>>> On
>>> Behalf Of Jim Barber
>>> Sent: Thursday, October 07, 2010 1:23 PM
>>> Cc: amps@contesting.com
>>> Subject: Re: [Amps] Autotuner for Amp Input
>>>
>>> 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
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>>>>
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>>
>>
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