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Anybody Have Any Idea How This Boom Headset Is Wired Up?

Discussion in 'General Technical Questions and Answers' started by WA3LKN, Aug 14, 2021.

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  1. WA3LKN

    WA3LKN Premium Subscriber QRZ Page

    This item (see photos) is currently for sale on ebay.

    It has the twin-plug arrangement that many HT's have had over the years, and they say it's compatible with a long list of Kenwood HT's.

    Here are my questions:

    1. If I use this with my HT, for example, in a PTT mode, does the in-line PTT button activate the in-line microphone at the in-line PTT button, or the boom microphone attached to the headset? What happens if I push the PTT button on the HT? Which microphone does that activate? 3 choices: The HT mic, the in-line mic, or the boom mic?

    My guess is the boom mic is only active with VOX.

    Anybody have one of these and can elucidate?

    2. Any reason I couldn't use this (with appropriate pin adapters) with a computer?

    1a.jpg a2.jpg
    Last edited: Aug 14, 2021
  2. WA9UAA

    WA9UAA Ham Member QRZ Page

    Probably a standard Kenwood HT layout. If you have a head set you could look up the layout, compare it to the common Kenwood Handi-talki pin outs and check the head set for function.
  3. KB0MNM

    KB0MNM Ham Member QRZ Page

    If the headset were manufactured by Otto instead of Retevis, the answers would be online or available with an e-mail. Generally, you would select either VOX or PTT mode with a switch. Then the PTT button would activate the transmitter in the PTT mode, or the VOX would activate the transmitter at a certain volume level into the boom microphone. The VOX function may require external bias, meaning that it might not operate as well on the PC as PTT should function. BTW- most PTT capable microphone circuits can be tested by wiring from ground to the PTT marked conductor. PTT circuits in microphones and headsets typically short the PTT conductor to ground for transmit function.
  4. WA3LKN

    WA3LKN Premium Subscriber QRZ Page

    I have an OEM Kenwood boom headset and what's different is the OEM in-line PTT arrangement doesn't include an in-line mic hence the question.

    And I do have the standard Kenwood wiring scheme.

    I think it will be a trial and error experiment.

  5. WA3LKN

    WA3LKN Premium Subscriber QRZ Page

  6. KB0MNM

    KB0MNM Ham Member QRZ Page

    To clarify, most electret microphones actually have a FET amplifier within the microphone element. That is the 'cup shaped symbol' at the lower right. A bias voltage of somewhere between 3 and 15 volts is typically supplied by the radio, and the resulting audio then is sent on that same wire from the element to the radio transmitter circuit. A PC may not supply the microphone with the same bias, yet might be adjusted with minor work at volume sliders or external batteries.
  7. WA3LKN

    WA3LKN Premium Subscriber QRZ Page

    Thanks very much! It might be simpler to get a low-cost dedicated boom headset for PC use.
    KB0MNM likes this.
  8. K6CPO

    K6CPO Ham Member QRZ Page

    Why would a headset have a boom microphone AND a microphone on the PTT button? Doesn't make sense...
  9. WA3LKN

    WA3LKN Premium Subscriber QRZ Page

    Agree. The only thing I can come up with is: They use that in-line device for other items that don't have boom microphones.
  10. KB0MNM

    KB0MNM Ham Member QRZ Page

    Some fancier sets have two microphones for noise-cancellation purposes, yet I doubt this is the case in the less-expensive ones. There is always the 'brother-in-law' case, in which extra details are an extra charge. ( My brother-in-law does/does not benefit from the cost of extra features or decals in the plastic ). It adds a lot of complexity to have a microprocessor compare two audio signals ( digitized ) and use the one with less noise. In a crowded room, noise-cancellation can keep the weaker signal from being repeated to the transmitter.

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