At 06:52 AM 6/1/2006, Steve Thompson wrote:
>Paul Christensen wrote:
>> K7FM:
>>
>>> Rich talks about prayer cloths - but in fact his nichrome suppressor is
>>> acting as a prayer cloth. This is a case of putting that in will make
>>> sure
>>> something bad will not happen.
>>
>>
>> Fuses.
>> Circuit breakers.
>> Lightning arrestors:
>> Discharge gaps.
>> VSWR alarm circuits.
>> Crowbar overvoltage protection.
>>
>> What do all these devices have in common with the parasitic suppressor?
>> Why, they are all "prayer cloths" designed to protect against something
>> can *could* happen, not necessarily something that is *pre-disposed* to
>> happen.
>
>Another thing in common is that they are sometimes used without
>understanding of what they do; without knowing if they do anything
>useful; and without consideration of whether alternatives can offer the
>same result. Like parasitic suppressors, they will rarely add any
>problems - but is that a reason not to discuss why things oscillate, or
>different ways of preventing oscillation?
>>
>> So here we are -- more than a decade later since these parasitic debates
>> began and we're still debating the use of a one-dollar component in
>> multi-kilobuck amplifiers.
>>
>> If we hire the best design engineers who do the best job they know how
>> to ensure that every component selected for an appliance will test
>> in-tolerance, and stay in-tolerance during the product's life cycle,
>> should we then eliminate fuses as being an unnecessary "prayer cloth?"
>> Or, if I build my home in the safest part of the country where no known
>> floods, lightning, hurricanes, tornadoes, sink holes, excessive winds or
>> other nasty environmental factors exist -- am I smart in terminating my
>> homeowner's insurance policy?
>
>Probably not, if you lose cover for fire, water leaks, accidental damage
>etc. As a different analogy, if you lived in San Francisco and had
>earthquake insurance, would you take out extra insurance against
>hurricanes? As you say, if it's cheap, why not, then it's something you
>don't have to think/worry about.
>
>Steve
I'd even go a step farther - I took the nichrome out of my SB-220, substituted
traditional suppressors, and picked up about 50 watts output on 10 meters. Not
a significant amount, but indicative of the amount of additional heat and
potential reliability problems. The amp remains very stable.
73, Pete N4ZR
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