开云体育

Aviation headset

pat griffin All Messages By This Member #25058 I just got Bitx40 working with no mods except 10-turn pot for tuning. I am using an aviation headset. ?Most of these have an electret mic (legacy since avionics in small planes are designed to handle old carbon mics). The typical mic response is 300-3500 hz which was also the ssb standard in the 60s and impedance is 50 to 600 ohms. Seems to work fine locally but no on-the-air response yet. ?Anyone else gone this route? 73
MVS Sarma All Messages By This Member #25059 Old Britishpost office and? in genetal older phones used to have these carbongranule microphones. ? It needs bias voltage to get signals out .say 12V dc with 5mA current. As the module is about 400 ohms to 1K, use another 2.2K in series to mic , like electret mic.The devil should respond well. All the best sarma ?vu3zmv ? toggle quoted message Show quoted text On Fri, Apr 14, 2017 at 6:52 PM, <patgriffin@...> wrote: I just got Bitx40 working with no mods except 10-turn pot for tuning. I am using an aviation headset.? Most of these have an electret mic (legacy since avionics in small planes are designed to handle old carbon mics). The typical mic response is 300-3500 hz which was also the ssb standard in the 60s and impedance is 50 to 600 ohms. Seems to work fine locally but no on-the-air response yet.? Anyone else gone this route? 73 -- Regards Sarma ?
pat griffin All Messages By This Member #26021 开云体育 Just a quick revisit to this topic. Per Sarma's suggestion I put 2.2k in series with the electret?mic and have been using an aviation ?headset (David Clark H10-13X) for a couple of weeks and have gotten good audio reports. Pat Griffin AA4PG http://www.cahabatechnology.com toggle quoted message Show quoted text From: [email protected] <[email protected]> on behalf of Mvs Sarma <mvssarma@...> Sent: Friday, April 14, 2017 8:48:10 AM To: [email protected] Subject: Re: [BITX20] Aviation headset ? Old Britishpost office and? in genetal older phones used to have these carbongranule microphones. ? It needs bias voltage to get signals out .say 12V dc with 5mA current. As the module is about 400 ohms to 1K, use another 2.2K in series to mic , like electret mic.The devil should respond well. All the best sarma ?vu3zmv ? On Fri, Apr 14, 2017 at 6:52 PM, <patgriffin@...> wrote: I just got Bitx40 working with no mods except 10-turn pot for tuning. I am using an aviation headset.? Most of these have an electret mic (legacy since avionics in small planes are designed to handle old carbon mics). The typical mic response is 300-3500 hz which was also the ssb standard in the 60s and impedance is 50 to 600 ohms. Seems to work fine locally but no on-the-air response yet.? Anyone else gone this route? 73 -- Regards Sarma ?

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