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Port-A-Lab 500d question


New Member
May 11, 2022
Found an old 500d. Has a good dummy load so worth keeping. I tried to use it just for fun to test SWR. Instruction sheet says for SWR it should first be calibrated to the 'SET' mark on the SWR scale while in the FWD mode. However, there is no 'SET' mark on that scale. Does anyone know if one of the numbers on the scale is perhaps the 'SET' mark? Thanks.

The end of the scale (far right side) on the SWR scale is set point.
knob: SWR CAL...Key radio adjust cal knob to set point...set knob to REV...key TX and read level
You must recalibrate every time you change frequency or power level!!

DO NOT expect that dummy load to handle more than about 25 watts PEP!
Many fried by overload by other owner's!
I have an original instruction sheet for the Courier Port-a-Lab 500, and from it created a PDF which is almost identical to the original. PDF attached.


  • Port-A-Lab_500_Instruction-Manual.pdf
    46.4 KB · Views: 74

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