Dear all,
I intend to replace the air coils in the LPF on my 475 kHz transmitter by toroid core coils. I have a stock of T200-2 cores but for the power level want to get
(500W would be required to get near the 5 W EIRP limit) one T200-2 is just on the edge in regard with the maximum flux (and thus temperature rise.
To be on the save side I would use 2 T200-2 toroids for each coil, and there are 2 options:
1. Glue 2 cores together to make one core of the double height.
This would reduce the flux to 70%, well under the limit. It would also reduce the number of windings to 70%, but due to the double coil height the wire length will increase slightly
(abt. 10%).
But as the cores have rounded egdes there wil be some air space between the wire an the core, what might increase loss.
2. Put 2 toroid core coils, each of half the inductance, in series.
This will also reduce the flux to 70%, but the total wire length needed will increase by abt. 40%.
In option 1 I will need lees wire (= less loss) compared to option 1, but the air space might undo this advantage.
So my question is: what will be best?
All advice is welcome.
73, Rik ON7YD - OR7T
