DIY dummy load resistor

Discussion in 'Homebrew and Kit Projects' started by WB9TEN, Nov 8, 2017.

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  1. KC8VWM

    KC8VWM Subscriber QRZ Page

    So the answer is no, you are not addressing the op's question about anyone having any experience using the specific resistors he has indicated his Ebay link to build a dummy load before.
     
  2. WA7PRC

    WA7PRC Ham Member QRZ Page

    You may wish to reread his post (emphasis and highlighting added):
    My answers to his questions are:
    • Not that EXACT part number but, the same type of parts.
    • Yes, it'll work fine, if you follow my suggestions.
    What do YOU contribute, Charles? o_O
     
    K7JBL likes this.
  3. WB9TEN

    WB9TEN Ham Member QRZ Page

    Thanks for the info. The difference between terminators and resistors was insightful and the temperature sensor is helpful too. Probably collect parts and build this over Christmas break.
     
    WA7PRC likes this.
  4. AI3V

    AI3V Ham Member QRZ Page

    Get some Teflon dielectric coax, it handles heat better.

    Connect the coax to the resistor with the shortest possible length of "stripped" coax going to the resistor.

    You will be fine to at least 2meters.

    Don't over think a hf dummy load :)

    Rege
     
  5. WA7PRC

    WA7PRC Ham Member QRZ Page

    That's what I used (RG-142/U) on my scrapped parts 1500W DL:
    [​IMG]
    The pigtail was scrapped, and came w/ a Type N female on one end. :)
    Total cost: zero.

    Bryan WA7PRC
    http://www.tinyurl.com/wa7prc-dummy
     
  6. VK2TIL

    VK2TIL Ham Member QRZ Page

    I'm late to this party; I've been away. Studying 150+ year old buildings is a refreshing change from the world of electronics. :)

    This subject has been covered here before; see, for instance, http://forums.qrz.com/index.php?threads/simple-diy-dummy-load.500117/#post-3651757

    If I were building the load seen in that thread again, I would use microstrip; it's simple to make using standard FR-4 PCB stock and those resistors are designed to mate with microstrip or stripline.

    I have some attenuator chips, very similar to those ceramic RF terminations/resistors, and I intend to build some power attenuators in this fashion one day.

    The OP's heatsink seems to be adequate for 100 watts; it probably has more area than my heatsinks.

    It's important to make a little "kink"in the resistor lead to allow for thermal expansion; the Florida RF website has an app note on this.
     
    WA7PRC likes this.
  7. KA9JLM

    KA9JLM Ham Member QRZ Page

    A good QRP dummy load is a #47 dial lamp.

    It fits perfect into a PL-259 after removing it tits.

    UHF and above makes it harder to get it right. Electronic tools can get expensive too.

    HF is a piece of cake.

    Radiating dummy loads are easier to build. :oops:
     
    WB9TEN likes this.

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