[AMPS] Re: Comm Qtrly Fall (Conjugate Match Article)

[Rich Measures]

>
>
>Amps Digest wrote:
>
>> Date: Fri, 28 Nov 1997 20:17:39 -0800 (PST)
>> From: Peter Gerba <pgerba@crl.com>
>> Subject: [AMPS] Comm Qtrly Fall
>>
>> In the mail today was the Fall "Communications Quarterly" containing a
>> fine piece: "Source Impedance of HF Tuned Power Amplifiers and the
>> Conjugate Match" by Jack Belrose, Walter Maxwell, Tom Rauch.
>>
>> Good reading !
>>
>> pete, kn6bi
>>
>
>I have a question about p36.....
>
>"He (Tom Rauch, W8JI) repeated Bruene's experiment (see FIGURE 4). Using 
>Bruene's method, Rauch obtained reflected power measurements similar to 
>Bruene's."
>
>What exactly was the method.....(I assume) of tuning and loading?
>
>Then the article says......
>
>"However, when Rauch tuned and loaded his PAs in the conventional manner 
>to obtain maximum output power with any given, fixed amount of drive, 
>there was a significant difference." .......da di da......"Thus Rauch's 
>experiment indicates that, when the amplifier is tuned and loaded for 
>operation in the conventional manner, the output impedance, Zout is close 
>to 50 ohms, and not a value five times greater."
>... ...snip...
However if Zout is 50 ohms and the load is 50 ohms, the efficiency is 
50%, not the 62 or so percent that we typically see.  It seems to me that 
62% efficiency would mean that Zout was 30 ohms.  
Rich...

R. L. Measures, 805-386-3734, AG6K   


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