Thanks John

You are welcome.

I have mentioned this previously and it is pretty obvious. If the core has a "high" permeability virtually all the flux from each turn is captured by all the other turns resulting in an effective inductance that increase as the square of the turns. At the other extreme if a core has a "very low" permeability or maybe even an air core a fraction of the flux from each turn is captured by the other turns causing the inductance to increase linearly with the number of turns. The classic "Wheeler" formula for inductance shows this linear increase for single layer solenoid type windings with an air core. Now a core material such as #2 which has a permeability of 10 which kind of in the middle. The Amidon formula assumes you are winding with a higher permeability material. If we assume that nearby turns couple better than turns which are farther away you generally see the inductance rise as sort of a square of the number of turns and gradually changing to a linear increase of the number of turns. Does this make sense? Larry, W0QE

@@w0qe Got it. Ya know ... there is a LOT of magic in RF and, to some degree, there is more magic with inductors than in some of the other things (it seems). I appreciate the fact that you answered. Thank you. 🙂

What is Sendust? Larry

These transformers do not have a high enough permeability for use at audio frequencies.

Sorry but I don't know of anything that I could point you to. Larry

JT, your eyes are fine and the 2 files I compared in the video were for slightly different conditions. I just repeated this exercise and all matched perfectly. I can only conclude that I made a mistake when making the video. Larry, W0QE

Absolutely yes. Assume the component in the RUSE block is an inductor(L1). Replace the hyphen below the component with "L1_ Q1" without the quotes. It will now act as you want. Larry, W0QE

Oops, hit reply too soon. If the RUSE block is named A then the voltage across an inductor in that RUSE block can be referenced as A.L1.v and also A.L1.V is the voltage from the dot end of the component to the circuit point labeled "gnd". I'm sure I have done this in several videos. Give it a try. Larry

I used an AIM 4170 analyzer in this video. However SimSmith/SimNec can read several other file formats most notably .s1p which can be created by the VNWA and the NanoVNAs. What VNA do you have? Larry, W0QE

@@w0qe I don't own any VNA's today, but Christmas is right around the corner. I'm looking at the nanoVNA V2 1.5 GHz (or higher) versions or the LibreVNA. What I'm wrestling with is how to calculate then simulate the internal termperature of an RF toroidal core (1uH inductor using T-68 powdered iron). I understand how to calculate the flux density of a core based on the voltage across the core, #turns, frequency, and Ae. But how do you calculate the Curie-Weiss temp effects on the core's permeability starting to drop? At 5:30 in this video, you state the heating effects on the coil are related to the voltage across it, not the current through it. What formula is this based on?

Gary, I am not familiar with the MAT-40 tuner or the dual step auto-transformers so I can't comment on your question. Sorry. Larry

You are welcome! Larry

Goodbye Karen!

You are correct that it was built exactly as it was supposed to be. I would be willing to bet that there are many of these surplus "Medical" Isolation transformers that many people have picked up believing that that they are "Lab" types.

Companies such as Micrometals, Fair-Rite, and TDK who make cores have inductor selection guides on their web pages which should help. Larry

No, the generator appears as a 50 ohm impedance. Otherwise the the reflection get re-reflected at the transmitter repeatedly. This can easily be simulated in LTSpice. Larry, W0QE

Glad you enjoyed it. Larry

Ryan, Ryan, I come from a family of engineers. My grandfather taught EE at the University of Pittsburgh, my dad was an EE designing megawatt power grid transformers, and I followed suit but mostly designed analog and digital circuitry in the70s through the 90s. Later I did RF and cellular work. Finally I spent about 10 years as a consultant doing RF work. My interest in amateur radio from 1964 through today was also an influence. 73, Larry, W0QE

Thanks. Larry

Bob, Version 15 of SimSmith is considerably different from version 16 and later when it comes to plotting. I addressed this in videos #47 and #57. SimNEC has all the features of SimSmith ver 18 and you do not need to use the NEC2 engine if it is not needed. There have been many small additions to SimSmith/SimNEC along the way and I really don't remember when a particular feature appeared but any video I produce will use the latest version of the program and hope that most folks are also using the latest version since the cost to upgrade is zero and only takes a few minutes. There are also occasional fixes for errors which only are in the newest versions. A video on the NanoVNA-H4 might is a good idea. Larry, W0QE

Bob, u' defines the inductance and u" defines the loss for inductive materials. John, KN5L has done a lot of work characterizing Fair-Rite cores. Look at www.kn5l.net to see how he analyzes the cores in SimSmith/SimNEC using the Fair-Rite published data and how closely the simulations match VNA measurements. Larry, W0QE

@@w0qe Thanks Larry your answer is on target and fits the bill. I've done a quick scan of the KN5L Website and come away impressed. There is a plethora of links and I have viewed only a few. This one is getting bookmarked. Lots of Signal, very little noise. Thanks again B

Thanks Mark. Larry

Several people have added bluetooth modules to do exactly what you want to do. I have such a module for my AIM 4170. Search for a USB to Bluetooth adapter. Larry, W0QE

@@w0qe Thanks for the reply Larry. I have been wondering how to use open wire feedline with the VNA. I am considering making a micro sma 1:1 balun adapter and a 1:1 unbal for each end. I found small commercially available sma antenna balun boards with a 9:1 balun but i also have seen the smd balun transformer available with a 1:1 winding. I was considering trying to make a 1:1 balun and a 1:1 unbal so i can add the length of the ladder line and it's velocity factor. I feel like i'm stepping into no man's land here. The other complicated factor is if making home made ladder line i would have to also calculate or measure the velocity factor and impedance. I might be stuck at this point or left to make some guesses. I'm guessing my line will be around 500 Ohms with a velocity factor between 85 and 90.

Thanks! Larry