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RCI69 base. Has RCI finally jumped the shark?

Discussion in 'CB and Export Equipment and Accessories' started by nomadradio, Feb 25, 2021.

  1. nomadradio

    nomadradio Analog Retentive

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    So here's a question. Has RCI finally jumped the shark?

    Here's what the latest "Black Radio" from RCI looks like on the outside. Yeah, a poorly-posed pic. Had more important stuff on the plate that day.



    [​IMG]

    Didn't get a lot of other shots before it had to go back together and go home.

    I did get this one. Leads me to the subject of my discontent. This radio sounds like poo on sideband transmit.

    Here's why, best I can tell. Too much gain packed too tightly together.

    [​IMG]

    The nasty sound of sideband transmit comes from RF feedback between the final stage and the low-power stages. Until this model, RCI radios had a tiny transistor buffer, followed by a small pre-driver (no heat sink) feeding the actual driver transistor, feeding into two parallel driver transistors.

    This thing has a driver transistor feeding into the driver transistor.

    In effect.

    Took me almost two months to get this posted. I'm curious what experience other folks have had with this new model.

    My idiot light is still glowing from when I realized I didn't write down or get a pic of the circuit-board's "EPT" type number.

    Was a busy week at the end of December.

    For now I'm not recommending this radio for sideband until I see a convincing way to make them stable.

    Yeah, that's kinda presumptive, based on experience with exactly one specimen.

    And if I never see another one again, that could be a clue all by itself.

    73
     
    Shadetree Mechanic likes this.

  2. 9C1Driver

    9C1Driver Sr. Member

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    Not to mention that RT-1 "final" is some kin of a transistor used in a power supply if I remember right.
     
  3. nomadradio

    nomadradio Analog Retentive

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    Another low-frequency switch MOSFET that RCI can get for a quarter apiece, scrape off the markings and stamp their number onto it.

    Rumor is that it starts out life marked as "IRFZ24".

    73
     
  4. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    Smoking Joes Electronics did up a Vid on the brother to this - it's Chromed cousin...
    RCI69VHP

    But there was a thread or two earlier...found one that showed the spectral rainbow of channels - er - harmonics...o_O

    https://www.worldwidedx.com/threads/rci-69-base.253568/

    Both chassis use the 12D version - so your photos and their board - well, I guess we could call it a match...

    One thing though, I still have to ask, what did they ever do for "X"? (That missing part?)

    That may be part of this problem...no turning down the output - because of no feedback being used can easily overdrive the following stages...
     

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