>
>
>>Gentlemen,
>>
>>My paint can oil-filled dummy load does not provide
>>the time duration necessary to achieve perfect tuning
>>as it gets very hot and pops off the vent cap in addition
>>to changing its internal resistance.
>>
>>Who makes a 3KW or better dummy load that's
>>affordable?
>>
>>There are BC quality units available and they are
>>between 1 and 2 thousand dollars.
>>
>>I would consider HB'ng a dummy load in a 5 gallon
>>metal bucket.
*** This post contains a typographical blunder -- i.e., Bird's
running-water cooled terminations are made from metal, Not plastic. The
one I am planning to build is constructed from standard plumbing
components and is mostly plastic.
>
>** The most practical way to cool a 50-ohm terminating resistor is with
>moving water. Bird Co. makes a series of terminations that do this. A
>sealed 3" ABS tube - with glued-on inlet and outlet garden-hose fittings
>- directs water around the resistor. 6-gallons per minute will carry
>away at least 15,000W of heat. To maintain constant Z with freq change,
>a tapered conductor is placed parallel with the resistor - with the
>widest spacing being at the coaxial RF connector end. I currently have
>a suitable resistor for building such a terminator on back order at
>Kanthal-Globar. I plan to use ordinary plastic pipe for the resistor
>housing. My estimate is that the cost of the plumbing material will be
>under $10 per water-cooled terminator. The water discharge can be used
>to sprinkle the lawn or garden.
>>
>>Your opinions and advice are always welcome.
>>
>>Hal
>>KA1XO
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>>http://lists.contesting.com/mailman/listinfo/amps
>>
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