Common Mode RF ChokeTester DIY

Common Mode RF ChokeTester DIY - Part 1

Рет қаралды 3,020

3 ай бұрын

This is a 2 port sensor/tester that is easy to build and easy to use.
Please note switching-in the 150 ohm resistor does not make the meter more sensitive.
I should have said it requires an increase of the "sensitivity control" to get a full scale calibration reading. This is only needed for much higher common mode currents than demonstrated in the video.

Пікірлер: 14

@wodowiesel 3 ай бұрын

Pretty cool and neat! Would like to see more of the diy things especially sma toroidal clips. Thx :)

@rfburns3472 3 ай бұрын

Thank you for your kind words. I hope to do some more vid's on DIY projects. Also, I may do a followup vid on how to construct those split toroidal transformers with the SMA connectors.

@clems6989 29 күн бұрын

A video showing how you built the clamp on sensors ??

@rfburns3472 28 күн бұрын

I really would like to do the video. Just need to figure out how to do the camera shots hopefully soon.

@Lugeix 11 күн бұрын

Replace the switch with a difference amplifier. Then read it in percent using an Arduino. Percent being amount of RF being choked.

@rfburns3472 10 күн бұрын

The Adruino is a good idea Lugeix. My design is simple and based on the "KISS" method.

@__logan__duvalier__ 22 күн бұрын

Is the return current on the coax outer not shorted out to ground at the cabinet coax feed through ? or is the metal cabinet not grounded ?

@rfburns3472 21 күн бұрын

Good questions Logan. The BNC receptical shields are insulated, therefore the coax outer shield is NOT grounded to the metal box. I did not want RF flowing about the box. Additionaly, I suggest using a metal box instead of plastic as my design is impervious to hand capacity affecting the meter reading when adjusting the sensitivity control.

@renaat9829 2 ай бұрын

Where did you get the schematic? In other schematics I see a 50 Ohm resistor in parallel just behind the pickup coil

@rfburns3472 2 ай бұрын

I created the schematic from various designs published long ago. For this passive device, a 50 ohm resistor is not recommended due to heavily loading down the sensitivity of the meter. In some designs, you may also note a diode placed across the meter to protect it from excessive current damage. But, this too decreases the sensitivity of the meter and is unnecessary if you exercise care and set the pot all the way down before energizing the coax under test. The 10 turn winding, on this toroid, presents very poor impedance match across the HF spectrum and therefore, the toroid if needed should be terminated with a 50 ohm resistor. See my video where I implemented this. kzfaq.info/get/bejne/etiaisKlxJfVoWQ.html

@ugiukito9449 10 күн бұрын

Hello RF Burns, question: I don't understand this "150" on the DPDT switch? Is there a 150 ohm resistor built in?

@rfburns3472 8 күн бұрын

Hello and welcome! The pole at the top of the DPDT switch has a 150 pf capacitor used to couple the RF energy to the diodes for rectification.

@ugiukito9449 8 күн бұрын

@@rfburns3472 Thanks rfburns 3472 I don't mean the capacitor in front of the diode, I mean the ON/OFF SWITCH between the rotary potentiometer and the ampere display on the diagram! It also says 150 but without a designation...? Sorry for my bad English, but great video and great idea with these two measuring probes! 73 Daniel

@rfburns3472 8 күн бұрын

@@ugiukito9449 OK Daniel I understand now. It's a 150 ohm resistor and switch that will change the sensitivity of the potentiaometer adjustment. It's optional and only needed if you have very high currents coming from the toroid sensors.