Re II: [AMPS] G2DAF AMPLIFIER CIRCUIT

[Lars Harlin]

At 17:23 1997-12-12 +0100, Rich Measures wrote:
>>Exactly how, did you do that Rich? 

>I used two**, double-filter receivers whose -60db bandwidth was <3.6kHz.  
>For a 2.4kHz transmitted bandwidth signal, I compared the signal strength 
>on frequency to the signal strength 3.6kHz above or below the signal 
>being measured.  For measuring a LSB signal, I measure the signal level 
>up 3.6KHz.  For measuring an USB signal, I measure the signal level down 
>3.6 kHz.  The offset must be such that it separates edge of the transmit 
>window skirt from the edge of the receive window skirt by roughly 40db.  
>If the two windows overlap, the relative measurements are not going to be 
>accurate.
  
>>What point in the the speech envelope did you use as reference?

>The detector was the S-meter/AGC circuitry, which normally uses a peak 
>detector.  

>>What word/phrase was used? 
>Ordinary speech, but NO swear words.  

Daffys never swear, as they have no reason to...;)

>>How did you establish a constant reference? 

>- The measurement was of differential signal level, not absolute signal 
>level.  The reference was the HP-355 1db/step attenuator set that was 
>used to generate a calibration graph of the S-meter reading/s versus real 
>decibels.  

>>What bandwidth did you cover? 

>garden-variety SSB.

>>How did the IMD products decay? i.e. what level at say 5 KHz from f0?

>I did not measure it.  I was not concerned with distant products.  I 
>wanted to see what the ratio (in db) of the signal level in the 
>fundamental window was compared to the signal level just outside the 
>window.  
>-  Every SSB radio and every linear amplifier generates splatter outside 
>the fundamental transmitting window.  A signal report of 'you are not 
>splattering' is abundant bovine feces.   The question is relatively, how 
>much splatter?   A signal report of S9 splatter is good if the 
>fundamental signal is 40db higher.  On the other hand, a signal report of 
>S6 splatter is not good if the fundamental signal is S9 (+18db).  
>{**a single receiver can be used to make the measurement by doing the 
>3.6kHz offset with the RIT.} 
-snip-

>>>Most people won't tell me when my zipper is down, Lars.  
>>
>>Rich...
>
>Thats to bad Rich, not only for me, but maybe even in a higher degree for
>you...! ;)
I got one e-mail saying that unzipped/fly down is called  'trolling for 
bimbos'  in Texas.  

>cheers, Lars
>Rich...
-snip-

Although I dont agree with the accuracy of your measurements on G2DAF amps
Rich, I do appreciate your sense of humour!

Whenever you go to Texas, Rich, - Good luck!! ;)

73´s de Lars
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Sweden
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