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From: Pete Smith <>
Date: Thu, 01 Jun 2006 07:14:40 -0400
List-post: <>
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.

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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