>
>I don't know how you test a new amp for stability
>but an unloaded state is the best way.
// VHF parasitic oscillation is always unloaded due to the tank
circuit's low-pass nature.
> If it's
>not stable unloaded then it's not stable. What
>the hell is "every amp manual" ?
>Paul
>
>Paul Hewitt
>WD7S PRODUCTIONS
>QRO HOMEBREW COMPONENTS
>http://wd7s.home.att.net
>
>
>> -----Original Message-----
>> From: Bill Turner [mailto:w7ti@dslextreme.com]
>> Sent: Wednesday, August 08, 2001 6:47 PM
>> To: wd7s@arrl.net
>> Cc: amps@contesting.com
>> Subject: Re: [AMPS] Linear AMP timing
>>
>>
>> On Wed, 8 Aug 2001 18:32:19 -0700, Paul
>> Hewitt wrote:
>>
>> >Hi Bill
>> >IMHO the best way to control
>> bias/cathode current
>> >is by means of solid-state switching.
>> It will be
>> >faster than either I/O relay operating at <2ms
>> >make and <1ms break. The bias (on/off)control
>> >transistor operates saturated so a
>> little goes a
>> >long way dissipation wise. I use the
>> same control
>> >buss for I/O relay control and bias switch.
>> >Paul
>>
>> ________________________________________
>> _________________
>>
>> I agree about solid-state switching,
>> but IMO, the tube should be still
>> biased off until switching is complete,
>> both input and output.
>> Otherwise, the tube could see a brief
>> unloaded condition, which has been
>> known to cause trouble.
>>
>> True, many amps are stable in an
>> unloaded condition, but every amp
>> manual I've seen advises against it.
>> I'd just rather be safe than
>> sorry.
>>
>> Bill, W7TI
>
>
>--
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>Problems: owner-amps@contesting.com
>
>
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
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