-----Original Message-----
From: Tom Rauch <w8ji@akorn.net>
To: amps <amps@contesting.com>; Steve Thompson <g8gsq@qsl.net>
To: <amps@contesting.com>
Date: 20 February 2002 01:07
Subject: Re: [AMPS] Power out indicator
>
>
>>> much lower working Q and so offer higher efficiency.
>
>>I'm wide open to
>> correction here, but I think If you are matching between two
>> resitances, the L match has the lowest loaded Q. To get lower, you
>> have to cascade L matches.
>
>Looking at a typical inductor Q=300 and capacitor Q=5000
>matching 50 ohms to 1000 ohms with 1500 watts on 1.83 MHz:
>
>L network Qeff=4.36 C=380pF L=18.96uH and loss = 25.7watts
>T network Qeff=4.7 C=389(2) L=19.45uH and loss=24.5w
>Pi Qeff=4.7 C=389(2) L=19.45 and loss=24.5w
>
>While the effective operating Q is slightly higher in the T and Pi,
>loss is lower.
I agree there's little doubt that the L network rarely has a significant
advantage compared with the tuning flexibility of the others. Correcting a
previous comment of mine, where there are reactive components to be matched,
pi/T can have lower loaded Q than L.
Steve
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