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Fredbox: 2m AM tcvr: Microphone testing |
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Written by Hans Summers
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Sunday, 28 June 2009 03:28 |
 | Loud whistle, about 10cm from microphone. Vertical scale is 1V/division, so the display shows 0 - 8V, measurement made at emitter of TR6. Supply voltage was about 8.3V. |  | Quiet whistle, about 10cm from microphone. Vertical scale is 1V/division, so the display shows 0 - 8V, measurement made at emitter of TR6. Supply voltage was about 8.3V. |  | Ordinary speech, about 10cm from microphone. Vertical scale is 1V/division, so the display shows 0 - 8V, measurement made at emitter of TR6. Supply voltage was about 8.3V. |  | Strange effect at the collector of TR4. After a loud whistle then silence, there is a slow and decaying oscillation of the voltage. Resting voltage is 1.0V when there is no sound. Width of this display is 2 seconds. |
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Last Updated on Sunday, 28 June 2009 03:40 |
