kube@ucbvax.ARPA (Paul Richard Kube) (09/11/85)
Now that it's seeing a lot of airtime near civilization, the old C120 is finally getting a radio. I would like to use a headset with this radio (those who have tried to hear themselves think inside a C120 above idle will understand). I have a headset, an Astrocom with a 5 ohm M-87 mike. The noise cancelling properties of the M-87 are wonderful, but at 5 ohms it is of course useless with civilian avionics. Question: What does it take to get the M-87 to live with standard radios? Just a transformer? If so, where does one get a tiny 5:50000 ohm audio transformer---or whatever the ratio is supposed to be? Or does it take some active circuitry? If so, does anyone have a circuit, or the story on what the parameters are supposed to be (input and output impedance and peak-to-peak voltage would do)? Paul Kube kube@berkeley ucbvax!kube