>
>Rich said:
>
>>This transformer needs to work at >150W.
>
>They can be made to work at high powers, but not necessarily the 'stock'
>design, as you say. Sevick is a good starting point for the theory. I think
some his
>designs were tested at high power. I do have a paper from a 1963
>conference on
>making 3-30 MHz xfmrs from 50 to 450 (or was it 600?) ohms which would do for
>you, Rich - they were rated at 40kW for SWR <1.5:1!
>
50? to 450?/1.8 - 29MHz/150w tested, is all I need.
>Interestingly, they were 'conventional' transformers. They used 'tubes' of
>ferrite, made up from individual toroid rings, like so many of the late Helge
>Granberg's Motorola designs. They put sheets of aluminium between the
>rings to act as cooling fins......
>
Temperature rise is usally an indicator of ferrite saturation/harmonic
generation.
>Of course, the easy way is to tune it with variable L and C......
Not if it's neutralized a lá Bruene's bridge circuit. Add a tuning
reactance to the grid, and one has a 10kW VFO. Been there, done that.
>...
cheers, Peter
- R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K,
www.vcnet.com/measures.
end
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