Amateur radio microphones

Discussion in 'Microphones, Speakers & Audio Processing' started by W4EAE, Jun 30, 2020.

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  1. W4EAE

    W4EAE Premium Subscriber QRZ Page

    I have worked with pro audio since my teenage years in the late 1990s. Since several decades before I was born, balanced lines have been used for microphones almost universally. Amateur radio seems to be a rare two-wire holdout. This seems strange as it would have clear benefits for radio.

    A relatively short 2-wire audio cable can pick up a lot of radio noise in certain locations. Substituting a balanced line eliminates this. Would the same not be true in radio?

    Additionally, a balanced line protects dynamic microphones from being damaged by ~48v phantom power. The only microphones I worry about with phantom power are ribbon mics.

    Has convention simply over-ridden practical innovation (if you want to call 70-year-old technology innovation), or is there some other solid technical reason?
     
  2. G0GSR

    G0GSR Ham Member QRZ Page

    Cost?
    Plus the fact that amateur mics are a lot closer to the first pre-amp than any studio/stage mics so they can get away with it.
    Also, the required signal to noise ratio from an Amateur system is far less stringent than in a pro set-up.

    A lot of radios now have a separate ground for the microphone so can mitigate to some extent against noise pick-up.

    Frank
     
    KB0MNM, K2XT and KW6LA like this.
  3. KM3F

    KM3F Ham Member QRZ Page

    Frank gave you a good answer on production and practical application.
    The problem comes when advanced audio is attempted in an RF setting.
    For example, I use balanced input to my advanced audio chain, keep balanced cabling then end up unbalanced to feed the radio.
    If proper attention is not paid to cabling and grounds along the way, Hum is the result.
    When this is all proper the Hum or noise absent or undetectable.
    So it depends on the application and who is doing it.
    When you monitor your own audio in an RF setting and hear any things not proper, be aware the head phones may be picking up RF and not always blame the audio chain until proven .
    I can monitor my chain output or the radio.
    Good luck.
     
  4. K8ERV

    K8ERV Ham Member QRZ Page

    I get rid of all noise by connecting that little center wire to the outer braid.
    Works for me.

    TOM K8ERV Montrose Colo
     
  5. W8AAZ

    W8AAZ Ham Member QRZ Page

    The needs of a normal ham rig installation and a professional sound installation are widely different animals. If you feel you must use balanced lo Z XLR mics for ham radio, Shure and others make inline transformers for as cheap as 18$. I am using one with a mic on a boom with a vintage rig now. I also have a classic desk mic that works just as well with that radio.
     

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