As I said in my previous post, my mcHF had been transmitting with 10W power after installing the new Mitsubishi mosfets. With the current goal met, a new target came into place.
More POWER :).
Here is the rear view of my mcHF RF board.
After few mods including the above one, my mcHF is now putting out a decent 15 W on 7 MHz :) .
More POWER :).
Here is the rear view of my mcHF RF board.
One of the modifications that was being discussed in the mcHF yahoo groups was for the T7 modification(Modification of the output transformer in the PA).
The existing transformer with 2:3 turns wound on BN43-202 core is not matched and is not efficient as it should be. The turns ratio needs to be 1:4 if you see output transformers in other push-pull amplifiers which use RD16HHF1 as the final mosfets. One solution to this is re-winding the T7 transformer to minimize the flux leakage. There is a proven way to accomplish this task.
Instead of using 1 binocular core, we use 2 and the primary will be wound with wire of maximum thickness. An innovative way of doing this is using the braid of coaxial cable-RG58 for winding the primary. Details of this can be found in mcHF Yahoo groups.
Below is the photo of the modified T7 transformer for the additional power output.
Below is the photo of the modified T7 transformer for the additional power output.
After few mods including the above one, my mcHF is now putting out a decent 15 W on 7 MHz :) .
