November Meeting and Presentation

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If you were unable to make the November meeting to pay next years dues ($20) please mail in your renewal. It is your continued participation and membership that keeps the club and our events going!

At the November club meeting Wes Cardone N8QM explained how to setup a signal generator to calibrate the signal strength meter (S-Meter) of a radio. This calibration of input signal was likely done by the factory. However, that may have been many years and much testing (or abuse…) ago. Despite the solid-state nature of recent radios the internals do still change over time and use. That means what used to read as S7 on the display may be an S3 or S8 now. To realign the meter with reality, we setup the signal generator to output a 1kHz tone over a 10MHz carrier. The peak to peak voltage on the signal generator was adjusted so that once it passed through the stack of attenuators it would be the 50μV of a S9 signal. From there, following the service manuals instructions the S-Meter can be reset to read S9.

Wes N8QM with radio and signal generator
Premise of an S-Meter and using a series of attenuators to bring the signal generator down to 50μV for S9.
Wes N8QM voltage calculation
Wes N8QM showing how to calculate the correct peak to peak voltage for the signal generator.

The club thanks Wes for the demonstration and presentation.

Some links to further reading about S-Meters, Peak to Peak voltage, and RMS voltages as some questions about them arose in the meeting.

Join us next time at the December meeting.


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