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[AMPS] Tuned Input, what me worry

To: <amps@contesting.com>
Subject: [AMPS] Tuned Input, what me worry
From: 2@vc.net (2)
Date: Tue, 9 Oct 2001 08:24:35 -0700
>
>Rather than build resistive pads, which involves calculating and soldering,
>it's easier to just coil up a bunch of RG58/U and cut it to the right length
>for the attenuation needed; then, open a beer and relax.
>
In my experiences, a longer length of RG-58/U seems to decrease input SWR 
of G-G amplifiers.  However, there is no, single, magic length of coax 
for the nine HF amateur radio bands.  The simplist solution is to use a 
tetrode (preferably with handles), neutralized, operating in Class AB1.  
When the grid's variable inductor resonates the grid-C on the operating 
frequency, SWR is minimal, and the tube is neutralized at the operating 
frequency.  

later, Steve
cheerz
>
>"Each success only buys an admission ticket to a more difficult problem." --
>Henry Kissinger
>
>> -----Original Message-----
>> From:        Steve Thompson [SMTP:g8gsq@qsl.net]
>> Sent:        Monday, October 08, 2001 11:48 PM
>> To:  amps@contesting.com
>> Subject:     Re: [AMPS] Tuned Input, what me worry
>> 
>> 
>> 
>> -----Original Message-----
>> From: Steve Katz <stevek@jmr.com>
>> To: 'KG6DV@cs.com' <KG6DV@cs.com>; amps@contesting.com
>> <amps@contesting.com>
To: <amps@contesting.com>
>> Date: 09 October 2001 00:03
>> Subject: RE: [AMPS] Tuned Input, what me worry
>> 
>> 
>> >
>> >Ron, doesn't a 1dB pad only provide 1dB of impedance stabilization?
>> >
>> >Think about it, and then have a beer.  I'll have one, too!
>> Nonono, beer first!
>> 
>> Anyway, a 1dB pad provides a 2dB improvement - drive power goes through
>> the
>> pad, some or all gets reflected, goes through the pad again before the
>> driver sees it. With 3 dB pad, you can't get worse than 3:1 VSWR, even if
>> the output end is open/short/any phase. A 6dB pad guarantees you about 2:1
>> max.
>> 
>> Steve
>> 
>> 
>> --
>> FAQ on WWW:               http://www.contesting.com/FAQ/amps
>> Submissions:              amps@contesting.com
>> Administrative requests:  amps-REQUEST@contesting.com
>> Problems:                 owner-amps@contesting.com
>
>--
>FAQ on WWW:               http://www.contesting.com/FAQ/amps
>Submissions:              amps@contesting.com
>Administrative requests:  amps-REQUEST@contesting.com
>Problems:                 owner-amps@contesting.com
>
>


-  R. L. Measures, 805.386.3734, AG6K, www.vcnet.com/measures.  
end


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