On Fri, 12 Sep 1997 12:00:34 -0700 randy starace <ke7tv@netzone.com>
writes:
SNIPS
of 160M in my Johnson Desk Kilowatt. They are easy to use and are not
>really effected by there surroundings but!!. You must use the
>formulas
>to calculate the heating effect of the freq and the Q etc. that they
>will be used in. The Alpha tank was built using the parts and
>knowledge
>available for the times, the cores are way too small for the
>culmlative
>heat that will build when they are in the RF field. The polymers
>holding the powder together will fail and the inductance will go way
>down. My desk running at class C 800 w cc fully modulated 3.2k pep,
>would need 4 of the 5 " cores stacked and insulated in a steady stream
>of air to stay hot at best. Amindon will send you an engineering book
>if you can come up with a company name.
>Dont get me wrong I think they are wonderful items in low power
>applications and rx circuits but one must over-engineere when using
>them
>in tank circuits.
>
>CUL 73
>Randy
Good point Randy. I noticed that the B&W PT2500A used even more toroid
mass in their little 2 x 3-500Z amp than the Alpha 77DX/SX. Both use the
standard Micrometals 2 mix. The shortcomings of the 77 series on 160 are
well known to most.
A minor point but an annoyance to me is the idea that Amidon produces
anything. They are STRICTLY a distributor of Micrometals and Fairite
Corp, etc, products. ANY engineering data is from the actual
manufacturer. As one who competes with Amidon, Palomar, etc ( at a
substantial savings) I wish to make that point very clear.
73...Carl KM1H
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