250W 50 ohm dummy load build using 250N50 resistor, NanoVNA troubleshooting CB HF HAM

[@anthonyvolkman2338]

I need to purchase some of those non-inductive resistors for my radio as well. They are quite nice I will admit.

[@fintechrepairshop]

I'm surprised how cheap they are. I was able to build this for $5 in parts. The resistor and the SO239 connector. I still don't know how hot they get. On 4 watts its not even getting warm .

[@anthonyvolkman2338]

@@fintechrepairshop They won’t really get hot till about 15 watts I’d say. The heat sink makes that number considerably larger.

[@jessicav2031]

The flying wires are an impedance discontinuity, which reflects RF. It might be easier to understand if you take a 2-port measurement of coax vs. single wires.

[@fintechrepairshop]

I'm learning, I'm starting to remember why I went down the computer science route. RF is tricky subject. Picking up that OfferUP box of CB stuff really kicked in my OCD. I'm finishing this radio stuff then I back on my 3D printer stuff. Need to machine my new hotend. Got the Celeritas going 120K Accell 1200mm/S. Still running 24V. I made weird observation, my TMC2204 drivers run cooler the faster the printer moves.