Well, I have two cantennas and have run both of
them at 2KW without any problems with SWR shift BUT
I've never left it key down more than about 1 minute continuous.
Both use transformer oil. I did build the "super dummy" project
in the handbook and it handles the higher power levels much
better but still gets VERY HOT after about 5-8 minutes at 2 KW.
Mark WB8JKR
On Wed, 3 Feb 1999 14:02:05 -0500 "Gilmer, Mike" <mgilmer@gnlp.com>
writes:
>
>Not knowing the innards of the Cantenna, may I suggest a quick test
>for
>the usefulness of simply a bigger can of oil. The test would be to
>see
>if the sides of the existing Cantenna are warm after the "10 or 20
>seconds" at 2KW claimed to be the maximum before VSWR change. If the
>outside of the can isn't warmer than before the test started, then a
>bigger can filled with more liquid will not help. It would seem that
>one would have to get the oil circulating around the resistor better
>to
>justify a larger reservoir. My guess is the can surface will NOT be
>any
>warmer.
>
>Is it true that the Cantenna's VSWR changes appreciably after 10 to 20
>seconds of 2KW?
>
>Mike N2MG
>
>> >> The Cantenna dummy loads just can't take 1.5 Kw for
>> >>very long. ........
>>
>> >You can use a 5 Gallon can which are usually throw aways from auto
>> body
>> >shops.
>> >With some creative work with tin shears, drill, and a propane torch
>> you
>> >can adapt the Cantenna as a unit.
>> >Thoroughly wash out the solvents in the can first!
>> >
>> >With 5 gallons of xfmr oil you can run 2KW for at least 20 minutes
>> and
>> >still maintain the Cantenna frequency response.
>>
>>
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