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List:       elecraft
Subject:    Re: [Elecraft] K3 - CQWW SSB Observations - R U kidding?
From:       Don Wilhelm <w3fpr () embarqmail ! com>
Date:       2009-10-31 23:53:18
Message-ID: 4AECCDEE.2030808 () embarqmail ! com
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Dave,

I can vouch for that statement.  I do use the Caddock Thick Film 50 ohm 
resistors as precision dummy loads.  They are flat up to 500 MHz with 
good mounting using no leads.  They MUST be mounted on a heat sink, and 
yes, they will go open in a flash if the rated power is exceeded (don't 
bother to ask me how I know that).

So, recommending them for a K3 application may not be the best, but if 
you want an inexpensive dummy load, got a heat sink from a defunct 
computer CPU cooling device and one of those resistors and connect it to 
a BNC or UHF jack using zero length leads - but don't exceed its power 
rating (they are available up to 100 watts).

73,
Don W3FPR

David Gilbert wrote:
> Metal film resistors are notoriously fragile.  They will typically meet 
> their published dissipation specs just fine, but they go from being OK 
> to being an open in a flash (literally) when overstressed.  I personally 
> would never use one in any application where the power they were 
> expected to handle wasn't rigid controlled.  Check with any industrial 
> control manufacturer and you will hear the same story.
>
> 73,
> Dave   AB7E
>   
>
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