[AMPS] al-1200

[Rich Measures]

>Subject:     Re: [AMPS] al-1200
>Sent:        3/29/1997 6:49 PM
>Received:    3/29/1997 8:06 PM
>From:        Tom Rauch (W8JI), W8JItom@worldnet.att.net
>To:          amps@contesting.com
>
>stratto wrote:
>> 
>> Last year at Dayton, I went by the MFJ booth to look at the al 1200. 
...snip...

>The strap is for neutralizing. 
Not in any engineering book I have seen.  
>There is a 180 degree phase inverting transformer under the chassis,
>connected to the filament. The circuit samples RF near the anode by
>capcitive coupling, inverts the pase 180 degrees, and applies it to the
>filament (cathode). 
>
>Heath and Gonset even used that system in some of their GG amps, ...snip...
........both of which earned a  reputation for oscillating .  Heath 
subsequently stopped using 'neutralizing'.  .  

R. L. Measures,ag6k,805-386-3734    


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