*President Adams II* Swing / Modulation

*UPDATED* Read the comments! News from Tiny Tim below about a modification to allow more swing and carrier modulation (photo below) It would be remise of me not to mention you’ll loose warranty, it could have impact on the legality of the radio and maybe shorten it’s life considerably! Needless to say it’s your radio and your soldering skills needed. Just wanted to mention the legal’s. Plus don’t want to get my ass kicked all around Balaruc and Naples about modifications.

Thanks to Tiny Tim! It’s very kind of you sending me the details.

Hello Simon, I have a nice mod for the president Andy to FCC radio that I’m happy to share for those that might like it. It really opens up the swing and carrier modulation. Simple one diode on the am regulator. Have a nice clear picture.

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  1. *NO*., that is NOT the proper way to perform what’s called a “PPE” (positive-peak-expansion) / Asymmetrical modulation modification, or as others call a “swing-mod” (in such “transistor-modulated”, architecture-type transmitters) as it can / will eventually cause some type of damage to the effected RF-power / modulation components, depending on how the end-user operates the adjustable power-control.!! 😦

    It MUST have a small trim-pot (value varies with radio model and RF finals) in series with the diode (I’m not even sure if that Anode end of that diode, is connected to the correct location…) and then MUST be adjusted with the help an oscilloscope, so as to be able to view the resultant AM, RF-envelope.

    And to also make the PROPER adjustments to BOTH the modulation percentage (at the “pinch-off” point) AND to the PEP limit (aka: saturation limit) of said RF-output device(s).

    Eric Klein
    Klein Communications
    Career Resume:


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