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omni30mmod [2017/04/29 13:51] n1ooq |
omni30mmod [2017/04/29 14:28] n1ooq |
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| The 56 pF capacitors are paralleled to total 112 pF, and the filter is wired as shown in the schematic. One side of the outer inductors is chosen as ground, and the taps are installed at the required number of turns up from this grounded end. | The 56 pF capacitors are paralleled to total 112 pF, and the filter is wired as shown in the schematic. One side of the outer inductors is chosen as ground, and the taps are installed at the required number of turns up from this grounded end. | ||
| + | ==Building the 9 MHz trap== | ||
| - | ==Adding the bandpass filter to the board== | + | One T50-6 toroid is wound with 15 turns of #24 magnet wire. Target inductance is 1.0 uH for this toroid. This inductor is paralleled with a 270 pF, 50V capacitor and a 20-100 pF trimmer capacitor. |
| + | 9 MHz trap schematic: {{:9_mhz_trap_-_schematic.jpg?300}} | ||
| + | |||
| + | The 9 MHz trap: {{:9_mhz_trap_-_photo.jpg?100}} | ||
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| + | ==Adding the bandpass filter to the board== | ||
| - | Bandpass board, bottom side, showing pads for 30m mod: {{:img0025a_-_edit.jpg?100}} | + | The stack is hot-melt glued to the bandpass filter board. It is attached vertically in approximately the same position as the Tentec transformer can for the original mod. There is a resistor which must be moved - see the Tentec instruction sheet. |
| + | Bandpass board, bottom side, showing pads for 30m mod. At left, output. At the center, ground. At right, input: {{:img0025a_-_edit.jpg?100}} | ||
| Bandpass board, top side, showing finished 30m filter mod (between bandswitch and the shield can at the right): {{:img0032a.jpg?100}} {{:img0033a.jpg?100}} | Bandpass board, top side, showing finished 30m filter mod (between bandswitch and the shield can at the right): {{:img0032a.jpg?100}} {{:img0033a.jpg?100}} | ||
