>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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