Dummy Load confusion

Discussion in 'General Technical Questions and Answers' started by DAMO666, Jul 12, 2021.

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  1. DAMO666

    DAMO666 QRZ Member

    Hello guys,

    Thank you all for the replies.

    I've been doing some research, & I've found that a Carbon Resistor when heated will exhibit reduced resistance as I'm witnessing with this Dummy Load - so it seems that what I'm seeing is probably normal behaviour although not good.

    After looking closely at the Resistor in this, I see it's a "ER50SP" Siliconised Carbon Resistor rated at 50W continuous use.

    I know Zetagi are renowned for exaggerating claims, but claiming this Resistor is capable of handling 1KW is nothing short of ridiculous.

    Here is the specification of the " TKK ER50SP" Resistor that's inside the Dummy Load: http://www.sanwatsusho-global.com/product/15/15_01_02.html

    I've checked this dummy load upto 145 Mhz on a friends rig, and at that frequency I'm seeing a SWR of ~1.2:1, so although not great, it's perfectly fine for HF use.
    Last edited: Jul 23, 2021
  2. WA9SVD

    WA9SVD Ham Member QRZ Page

    It probably CAN handle a Kw. For about two seconds... and then, (as the Raven would say,) Nevermore.
    DAMO666 likes this.
  3. KM3F

    KM3F Ham Member QRZ Page

    If you want a near flat load, put an adjustable tuning Capacitor on the ground end in series with the load resistor and tune out any inductive reactance at the frequency of interest.
    DAMO666 likes this.

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