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Re: [Amps] 20kw Dummy load?

To: <r@somis.org>
Subject: Re: [Amps] 20kw Dummy load?
From: "Michael Tope" <W4EF@dellroy.com>
Date: Fri, 24 Sep 2004 06:16:46 -0700
List-post: <mailto:amps@contesting.com>
----- Original Message -----
From: <r@somis.org>

> Michael -- Have you ever measured the resistance of an MFJ  or Heath
> Cantenna After 1-minute of  NØN (hammer-down)  at 1500W?
>

No, not directly, but VSWR didn't appear to change appreciably when I ran
1 minute key down test last week. This suggests that the resistor value
remains reasonably stable. The oil gets damn hot, however :)


> > Seems like
> > conduction cooling between the can body and a water bath
> > would be of some benefit.
>
> In a long test, yes, but the main problem is bubbles forming in the
> cooling oil at the surface of the resistor.
> cheers

The other thought I had was to snake copper cooling tubes into the
oil reservoir to form a heat exchanger. Also has anyone tried active
stirring of the oil to reduce localized heating of the oil near the resistor
surface? Just random thoughts.

73 de Mike, W4EF...........................




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