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MY CMC MEASUREMENT

#measurement

Peter Ivanooff All Messages By This Member #20500 In the mid-January, my old 80m dipole broke due to icing and heavy snow. It had a direct connection with a coax for too many years .... and I decided to be with a Choke when the Weater improve.I started tests with several noname ferrite toroids and nanoVNA-H v.3.3. After some measurements (according to Fair Rite ) the toroides turned out to be MgZn, 40x25x11mm with Initial ?i 2000 or a bit more. Stacked two with 14 turns 1.12 mm enameled wire in thermo shrink tubing (max diameter 2mm - the toroids are small). Normal winding .... tested and Reisert style... the same result.To avoad fixture capacitance I connected the Choke direct to calibrated plane of nanoVNA CH0 - CH1. Used nanoVNA alone, after with NanoVNA Saver, and OneofEleven application. Full House with Data ...I've made a try to burn the choke with my PA and 250W noninductive dummy load (with some pauses).KEY Down on CW and 175 volts p/p on Tektronix osci. That is 612 watts on the peaks....The core and windings were cold as before the test ...I know the real test is up on the feedpoint of the antenna.... Seems the Choke can be used on 3.5Mhz- never have had 1.8 Mhz.Only 3.5-432Mhz. The screenshots are attached. Will be good some Expert to say something about this Choke....till I waiting for FT240-31 toroids. Best Regards ! 2xUnknown ferrite CMC-Saver.png 2xUnknown ferrite CMC-Saver2.png 2xUnknown ferrites CMC-1 of 11.png No Fixture with another Choke.png
Miro, N9LR All Messages By This Member #20534 On Sun, Feb 7, 2021 at 09:21 AM, Peter Ivanooff wrote: Full House with Data ...I've made a try to burn the choke with my PA and 250W noninductive dummy load (with some pauses).KEY Down on CW and 175 volts p/p on Tektronix osci. That is 612 watts on the peaks....The core and windings were cold as before the test ...I know the real test is up on the feedpoint of the antenna.... You did not get power correctly :) P=Vrms^2/R, so if you have Vpp=175V (peak to peak), Vmax=Vpp/2=87.5V and Vrms=Vmax/sqrt2=87.5/1.41=62V and P=77W on 50ohm load
Miro, N9LR All Messages By This Member #20535 On Sun, Feb 7, 2021 at 09:21 AM, Peter Ivanooff wrote: the toroides turned out to be MgZn I suppose you meant MnZn (Manganese-Zinc)
Miro, N9LR All Messages By This Member #20536 On Sun, Feb 7, 2021 at 09:21 AM, Peter Ivanooff wrote: .I started tests with several noname ferrite toroids Chances are that I'm not interpreting your setup correctly, but based on the picture with choke and nanoVNS, you were only testing the DM mode - impact of your choke on power sent from one side to the other side of your choke. You need to test the CM (common mode) suppression, and that get's done differently - for example, you short both sides Would be great if you can clarify your test setup and then mention what attached screens shots are for :)
W0LEV All Messages By This Member #20547 Your measurements look much like mine. However, as has been previously pointed out, your power calculation is in error. 77-watts is the correct value. Dave - W?LEV toggle quoted message Show quoted text On Sun, Feb 7, 2021 at 3:21 PM Peter Ivanooff <gp2zl2gpg@...> wrote: In the mid-January, my old 80m dipole broke due to icing and heavy snow. It had a direct connection with a coax for too many years .... and I decided to be with a Choke when the Weater improve.I started tests with several noname ferrite toroids and nanoVNA-H v.3.3. After some measurements (according to Fair Rite ) the toroides turned out to be MgZn, 40x25x11mm with Initial ?i 2000 or a bit more. Stacked two with 14 turns 1.12 mm enameled wire in thermo shrink tubing (max diameter 2mm - the toroids are small). Normal winding .... tested and Reisert style... the same result.To avoad fixture capacitance I connected the Choke direct to calibrated plane of nanoVNA CH0 - CH1. Used nanoVNA alone, after with NanoVNA Saver, and OneofEleven application. Full House with Data ...I've made a try to burn the choke with my PA and 250W noninductive dummy load (with some pauses).KEY Down on CW and 175 volts p/p on Tektronix osci. That is 612 watts on the peaks....The core and windings were cold as before the test ...I know the real test is up on the feedpoint of the antenna.... Seems the Choke can be used on 3.5Mhz- never have had 1.8 Mhz.Only 3.5-432Mhz. The screenshots are attached. Will be good some Expert to say something about this Choke....till I waiting for FT240-31 toroids. Best Regards ! -- Dave - W?LEV Just Let Darwin Work
Peter Ivanooff All Messages By This Member #20552 On Mon, Feb 8, 2021 at 03:02 PM, David Eckhardt wrote: David, Thanks for: "our measurements look much like mine." Followed Yours and K6JCA, W2DU, G3TXQ and other Experts recommendations... only with my nanoVNA " Miro, OK for "MnZn" it was my tipomistake Please read my post again.I only and only talked / wrote about the voltage and power of the peaks.At the peaks,the toroid and the coils are loaded with this voltage and power. The dog is buried there. This is the maximum and real stress that the choke experiences at the peaks.The arcing between wires is always on the peaks. PA - Tube with 1900 volts on Anode/ 0.5 A plate current (DC) when the PI filter is set to max output power on 3.65 Mhz.. LOAD - 250 watts non-inductive load up to 3 Ghz on a solid radiator (I had to pause so as not to blow it) is heated to 80 degrees Celsius for 30 seconds Nonstop test.The Choke NO - it remained relatively cold. KEY DOWN ON CW is very good test....Nothing less, nothing more.. I can't say Best Regards ! Thanks for the Comments !
Miro, N9LR All Messages By This Member #20569 On Tue, Feb 9, 2021 at 02:10 AM, Peter Ivanooff wrote: PA - Tube with 1900 volts on Anode/ 0.5 A plate current (DC) when the PI filter is set to max output power on 3.65 Mhz.. LOAD - 250 watts non-inductive load up to 3 Ghz on a solid radiator (I had to pause so as not to blow it) is heated to 80 degrees Celsius for 30 seconds Nonstop test.The Choke NO - it remained relatively cold. Just to get us "more scientific" and enable others to use and rely on your experience, would be great if you can provide "set up and measurements" in SI units instead of in descriptive statements :) 1) Power dissipation of the PA (tube) can be irelevantan - it only tells how much heat will dissipate inside the amplifier. Without knowing how much power was "send" by the power supply, or even better how efficient is the amp, we can't conculde how much power was sent to your dummy load 2) I suppose that your dummy load is 50 ohm 3) Stated power of the load (250W) does not tell much. It's usually "power rating for given duty cycle" (for example: 100W @1hr, 250W @1min, 1000W @2sec) The most helpful will be if you can connect your oscilloscope to the dummy load (mind the max voltage prorated for frequency) and measure either "peak to peak" or "max" voltage. Keep in mind that "p-p" (between + and - maximum) is double of "max" (zero to maximum). From that, it will be easy to calculate the power your balun is handling as P = (Vmax/1.4)^2 / 50. If you expect that that you have 250W delivered to your load, you should see Vpp = 21.4sqrt(250*50) = 313V
Peter Ivanooff All Messages By This Member #20574 Halloooo.... miro - Your answers are nagging. Only bla, bla, bla. Every very, а very little smart student will understand what I talking for ! Only for Peaks ! See the attachment now- to learn what is Peak for AC voltage. And No, my till 3 Ghz dummy load is 5000 Ohms ! Special chip resistor on solid 5000 Ohm radiator too. Ha, ha , ha...you never will get such The Power was enough to burn balls of brass monkey like you.Use Internet calculator to calculate how much peak power 175 volts on peak gives. Peak.png
Dragan Milivojevic All Messages By This Member #20602 You wrote: "KEY Down on CW and 175 volts p/p" Please behave like an adult. toggle quoted message Show quoted text On Wed, 10 Feb 2021 at 08:35, Peter Ivanooff <gp2zl2gpg@...> wrote: Halloooo.... miro - Your answers are nagging. Only bla, bla, bla. Every very, а very little smart student will understand what I talking for ! Only for Peaks ! See the attachment now- to learn what is Peak for AC voltage. And No, my till 3 Ghz dummy load is 5000 Ohms ! Special chip resistor on solid 5000 Ohm radiator too. Ha, ha , ha...you never will get such The Power was enough to burn balls of brass monkey like you.Use Internet calculator to calculate how much peak power 175 volts on peak gives.
Miro, N9LR All Messages By This Member #20606 On Wed, Feb 10, 2021 at 01:35 AM, Peter Ivanooff wrote: Halloooo.... miro - Your answers are nagging. Only bla, bla, bla. You are right! I just assumed that you are genuinely interested in this subjects, but as many others using nanoVNA not formally educated in this "branch of science", so I tried to word it in a way that even a beginner can understand. Now I see that I have made mistake, you do have "knowledge", even have a diagram that shows correct terminology, but are just sloppy with terminology and plain rude dude. Should have said "check your question/statement as they make no sense. Once you do it all the rest will get addressed on it's own". Obviously my bad! Won't even dignify your other comments that have no place in this group.

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