[Amps] Transistor amps

[Tony King - W4ZT]

Those are very interesting!  I noticed that the 9701 paper mentioned an 
interesting problem in the input circuit relating to the wild excursions 
of input impedance and the fact that, under some conditions of tuning, 
the amp may not even turn on until the drive level reaches a point that 
is near the level used to adjust the amp making it "snap" on.
Thanks for sharing,
Tony W4ZT

Dr. William J. Schmidt, II wrote:

>Check these out... I just uploaded them to my website.  They make fine CW 
>amps... need a little work for SSB... but not much!
>
>http://www.wjschmidt.com/ham/apt9502.pdf
>
>http://www.wjschmidt.com/ham/apt9701.pdf
>
>Sincerely,
>
>Dr. William J. Schmidt, II  K9HZ
>Trustee of the North American QRO - Central Division Club - K9ZC
>
>Email: bill at wjschmidt.com
>WebPage: www.wjschmidt.com
>
>"If computers get too powerful, we can organize them into a committee; that 
>will do them in."  -- Bradley's Bromide
>
>
>----- Original Message ----- 
>From: "Will Matney" <craxd1 at ezwv.com>
>To: <amps at contesting.com>
>Sent: Monday, March 28, 2005 8:54 PM
>Subject: Re: [Amps] Transistor amps
>
>
>  
>
>>William,
>>
>>If things convert over to solid state, that is what's needed, a high
>>voltage semiconductor. This I am interested in and wouldn't mind building
>>a prototype. One thing about mosfets I was told is you can parallel them.
>>You can parallel say 4 on each side of a push pull amp (8 total) to
>>increase it's power. This way, you dont have to worry about all those
>>splitters and combiners.
>>
>>Thanks,
>>
>>Will
>>
>>*********** REPLY SEPARATOR  ***********
>>
>>    
>>
>>>On 3/28/05 at 7:38 PM Dr. William J. Schmidt, II wrote:
>>>
>>>      
>>>
>>>>Frequency response rolls off too much for those transistors.  They were
>>>>made
>>>>to work below 2 mhz.  HOWEVER, there are the high voltage mosfets from
>>>>Advanced Power Technology that work in the 300-1,200 VDC range deserve
>>>>discussion.  The devices are targeted for RF designs  < 75 Mhz, and are
>>>>very
>>>>cheap by most measures (not Rich).  Lots of class "E" circuits for
>>>>        
>>>>
>>>them...
>>>      
>>>
>>>>APT has many app notes on them... check them out!
>>>>
>>>>Sincerely,
>>>>
>>>>Dr. William J. Schmidt, II  K9HZ
>>>>Trustee of the North American QRO - Central Division Club - K9ZC
>>>>
>>>>Email: bill at wjschmidt.com
>>>>WebPage: www.wjschmidt.com
>>>>
>>>>"If computers get too powerful, we can organize them into a committee;
>>>>that
>>>>will do them in."  -- Bradley's Bromide
>>>>
>>>>
>>>>----- Original Message ----- 
>>>>From: "Will Matney" <craxd1 at ezwv.com>
>>>>To: <amps at contesting.com>
>>>>Sent: Monday, March 28, 2005 7:08 PM
>>>>Subject: [Amps] Transistor amps
>>>>
>>>>
>>>>        
>>>>
>>>>>This is something I have thought of for years and never looked into it.
>>>>>Could an amp be built using horizontal output transistors where the
>>>>>voltage can be ran up to keep the current down? I wonder if any would
>>>>>          
>>>>>
>>>>work
>>>>        
>>>>
>>>>>up in this frequency range (2-30 MHz)?
>>>>>
>>>>>Will
>>>>>
>>>>>_______________________________________________
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>>>>>
>>>>>          
>>>>>
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>>>>
>>>      
>>>
>>*********** END FORWARDED MESSAGE  ***********
>>
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>>    
>>
>
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