On Wed, 27 Aug 1997 08:57:31 +0008 "George T. Daughters"
<gdaught6@pobox2.stanford.edu> writes:
>
>hi tom,
>
>> Are you sure? Why does a HF PA have a 4:1 transformer in the tank?
>> That seems non-conventional.
>
>pretty non-conventional, but the plate tank (pi circuit) matches from
>the anode level down to 200 ohms, then the transformer gets you down
>to 50, nominal. at the very leaset, it means you don't need an rfc to
>ground
>for safety. i haven't done the calculations, but it might end up
>looking like a
>pi-L output network.
>
>what i'd really like to know is what sort of troubles with the
>transformer can be causing IMD ratings to change?
Once overheated beyond a certain point the cores become permanently
non-linear. This is particularly true with ferrite. Powdered iron can
develop fractures which result in similar problems. I do not know what
materials QRO and Command use for their 4:1.
73....Carl KM1H
>
>73,
>George T. Daughters, K6GT
>
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