With invaluable help from Bob/k6rtm I put together this power inserter using a gutted cable TV splitter. The only part I needed to buy was the 47 picofarad capacitor. I didn’t have an inductor, so Bob suggested making an inductance coil. I used 7 turns of 22 gauge telephone wire with the coils roughly 1/8 inch in diameter (actually, slightly smaller). I wrapped the wired around a piece of 12 gauge copper wire. It works great! Easy to make. Save your money.
Edit: Added captions to photo