| #29: Adding a S-meter to TenTec 1254 Shortwave Receiver W2AEW |
| #29: Adding a S-meter to TenTec 1254 Shortwave Receiver This video shows how I added a relative signal-strength meter (S-meter) to the TenTec 1254 SSB, CW, AM Shortwave Receiver kit. I built this kit last year, and really enjoy it. I did a video a few months ago that showed a walk-through of its circuitry. One downside to this radio is that it does not have a S-meter, so I decided to add one. I measured the AGC voltage vs. input signal strength, and plotted this result to better understand the voltage range I was working with. Then, I designed and built an expanded scale voltmeter that would respond to the limited voltages that the AGC circuit produces. This video shows the circuit schematic, the completed prototype, and its operation. https://youtu.be/5yhMOcpHS7Q |