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Jeff, your fixture is virtually identical to what I built. My BNCs are a bit closer to each other, but just about the same. I also use the same fixture to characterize ferrite Z to match to the

Here is some measurements I did on a commercial NooElec FM Band Reject filter. One is a screenshot taken on a NanoVNA-H4 and the others are from NanoVNA Saver of the same filter. Markers are at the

Hi all is it poossible for anyone to send me a couple of example captures of filters ? Im, doing a vna prese3ntation and dont have a filter to measure and show. vnasaver will do fine thanks

...and attached please find the promised photos: - Jeff, k6jca

Thanks very much, Dave. In addition to my CMC having about 2K more CM resistance, it peaks at about 21 MHz, whereas yours seems to peak somewhere in the range of 7 MHz (very roughly). I'll have to

Hi Manfred, Could you please explain what you mean by "end-to-end"? There are four "ends" in the CMC and I'm trying to understand which ends you are referencing -- input-pair to output-pair, or

So far, so good, regarding impedance. The other point one needs to look at is power handling, or rather, core losses per applied voltage. With that core, and 12 turns, approximately 170V RMS, end-to

See the pictures of T240-31 core and coax. I use these? from 3.5 Mhz to 10 MHz as CMC 73, Arie PA3A

BTW, the general shape of your real part of Z looks extremely similar to my overall curve. You obtained about 2k more CM resistance, but the shapes are nearly identical. Dave - W?LEV wrote:

1. Does your data represent |Z|, or is it the resistance of the CMC impedance? (Note that I'm plotting the resistance, because, to me, this is the more important parameter of a CMC). I am plotting

Hi Dave, Looking at your data, I see that it differs from my plot of 12 turns of #14 twisted pair on the same type of core (see attached plot). I would like to detemine why, so a couple of

Based on the cookbook plus have two single #31 cores in series with 15T and 11T using salvaged 12 AWG wire. So using all the good data here from the fabulous Dave W0LEV, and K9YC, will I have >5K

To make things even easier, I recommend using a SMA bullet with a knurled center section, such as ebay item # 202670005403.

It is stated below that the work is in progress to support "all" versions of nanovna but it is unclear what is meant by "all". You may join the group and ask

Subject: single 31 material 2.4" OD core 12 bifilar turns of insulated AWG #12 stranded wire 1.90 MHz 3.0 kΩ 3.75 MHz 4.3 k 7.15 MHz 4.5 k 10.125 MHz

Try making a stable oscillator using ferrite in the inductor. That's why all the MFJ QRP transceiver offerings drift like crazy (I've had and 'fixed' a few in my years of hamming!!). If you want a

which of the various combinations is the complete system TIA G1WXC

Jim Lux, I checked some catalogs. Amidon specifies ?i for most materials with a ±20% tolerance, while material 75 (?i=5000) has ±30% tolerance. Thomson Ferrinox does a similar thing, specifying

And don't neglect the fact that most ferrite materials exhibit a rather strong sensitivity of ?r with temperature. That's the main reason that the flux gate magnetometer usually using ferrite

Jim KA6TPRO, In my message #19995 I mentioned this! Of course any equation involving permeability is only valid with the actual permeability the material has under the applicable conditions, which