>
>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
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
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