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Thread: FTD-450D and the Collins 30L-1

  1. #1

    Join Date
    Sep 2018
    Penn Yan, NY

    Default FTD-450D and the Collins 30L-1

    Can the Collins 30L-1 be connected to my FTD-450D? If so what is required. Any help is appreciated. Thanx.

  2. #2
    K7KBN's Avatar
    Join Date
    Jul 2008
    Bremerton WA USA


    If you have the manuals for both, you'll be able to figure it out. Keying the old amplifier might be a trick with an external relay; the radio might not be able to handle keying voltage/current.
    Pat K7KBN
    Semper ubi sub ubi.

  3. #3


    A quick look at the manuals and schematics leads me to this assumption (i give no guarantees, use this at your own risk):

    The amplifier antenna relay appears to be powered via a negative 120VDC supply. (FYI, if the schematic is right, that jack supplies a lethal current with respect to the amplifier case.... beware!) It would seem that shunting this to the amplifier case would activate the amplifier relay. The manual for the FT-450 suggests that pin 1 on the linear jack is 13.8v and pin 2 is ground during tx. I would assume that if pins 1 and 2 of the radio linear jack are used to activate a 12v relay, and the relays normally open contacts (being isolated from the 12v activation coil) are used to connect the center wire of the amplifier ant relay phono plug to its shield or amplifier case, the radio would then key the linear. Just DON'T try to use the linear jack directly with the negative voltage on the linear, you will toast your radio! Also, ensure the 12v relay you use draws UNDER 400mA (max rating for T/R control transistor)! Relays that draw 30mA are common and would be fine.

    Also keep in mind that the FT-450 is a 100w radio, which is the upper limit of the amplifier drive requirement. Without the ALC connection, it would be potentially easy to overdrive the linear! I would keep the transceiver output under 70w if you are not using the alc connection and keep a close eye on the plate current. I see nothing in the yaesu manual about the actual voltage levels the ALC circuit uses and lack the confidence to comment on that.

    I take no responsibility for how you use this information. I have little hands-on experience with this sort of thing, I am no expert!

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