[Amps] 20kw Dummy load?

[R.Measures]

On Sep 24, 2004, at 6:16 AM, Michael Tope wrote:

>
> ----- Original Message -----
> From: <r at 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.

I agree.  Thanks.

> The oil gets damn hot, however :)

Setting the Cantenna in a bucket of water helps.
>
>
>>> 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...........................
>
>
>
>
>
>
Richard L. Measures, AG6K, 805.386.3734.  www.somis.org