Tnx Phil...when and where were the articles published, I may have them
somewhere in the attic.
73 Carl KM1H
On Sun, 15 Nov 98 20:03:12 PST "doshhan" <doshhan@vaxxine.com> writes:
>
>
>I haven't bothered to digest this completely, but I do have at least 2
>articles that show that serious errors exist in the calulated 'Q' of
>Pi/Pi-L networks when using Handbook formulas. These errors are still
>in effect (ie. they haven't been corrected) in recent editions of the
>ARRL handbook. Not sure if this is what you're after but I can send
>copies of the articles if you want them.
>
>Phil Turcotte
>VE3OZZ
>----------
To: <amps@contesting.com>
>> Date: Friday, November 13, 1998 16:53:03
>> From: km1h@juno.com
>> To: amps@contesting.com
>> Subject: Re: [AMPS] Pi-L networks
>>
>>
>>
>>
>> On Fri, 13 Nov 1998 12:47:23 -0000 Peter Chadwick
>> <Peter_Chadwick@mitel.com> writes:
>> >
>> >Does anyone have any comments about the Q of the L network section
>in
>> >Pi-L
>> >networks? I have seen it suggested that the impedance at the middle
>of
>> >the
>> >pi-L should be the geometric mean of the input and output
>impedances:
>> >the Q
>> >of the L will then be given by
>> >
>> >Q = sq.rt.(Ri - Rl)/Rl
>> >
>> >where Ri is the intermediate impedance in the Pi-L (i.e. the
>geometric
>> >mean)
>> >and Rl is the load impedance (usually 50 ohms)
>> >
>> >For an 1800ohm plate load, this gives a Q of 5 for the L section,
>> >which
>> >appears to be the right order of magnitude.
>> >
>> >Of course, the Pi section would run at the usual Q - 10 to 15, or
>so.
>> >
>> >Comments, please?
>> >
>> >73
>> >
>> >Peter G3RZP
>>
>> Peter,
>> I thought the same until I started to actually use that concept
>> Peter....wound up with higher than expected voltage at the Load
>> capacitor....read "arcs".
>> By formula that should not have occured leading me to believe that
>there
>> is more to it than static design on a piece of paper.
>> I now "design" for a Q of 2 to 3 in the L and have had no further
>bad
>> experiences. The spectrum analyzer confirms the L is performing as
>> expected.
>>
>> 73 Carl KM1H
>>
>>
>>
>> >
>> >--
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>> >
>> >
>>
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>
>
>
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___________________________________________________________________
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