Diagnosis of a 9:1 transformer from NanoVNA plot discussed an example measurement of a 9:1 transformer on a binocular ferrite core. These are often recommended for use with Beverage antennas on 160 and 80m bands, and this was the maker’s application. In that article, I hinted that the core might not be #73 as the maker … Continue reading Diagnosis of a 9:1 transformer from NanoVNA plot – part 2
A chap recently posted online a question: I have added two 1:9 transformer (2T/6T) back to back (high side together) and measured with the nanovna – 2 port measurement, as the binocular core I am not confident BN73 or not. Also I swiped with one port S11, with one transformer where the high side is … Continue reading Diagnosis of a 9:1 transformer from NanoVNA plot
A correspondent asked whether Sontheimer coupler – transformer issues – an alternative design – FT37-43 could be used to inform design of a 49:1 EFHW transformer based on the same core, but with a 2 or 3t primary. In the case of the Sontheimer coupler the winding with the higher number of turns appears in … Continue reading FT37-43 for a 49:1 EFHW transformer enquiry
Nanosaver v0.4.0 contains a graph that I have found difficult to understand, much less find application. Above is the graph scaled R/ω and jX/ω, and an untitled X axis, though it would appear to be frequency in Hz (scaled by the M multiplier). I had difficulty reconciling the Y values plotted for R/ω and jX/ω … Continue reading Trying to make sense of Nanosaver’s R/ω and jX/ω graph
Sontheimer coupler – transformer issues discussed problems with the Sontheimer coupler in a recently published QRP transceiver ((tr)uSDX / trusdx), suggesting that the core loss in transformer T2 was excessive. This article presents an alternative design for the transformer for a coupler for a 5W transmitter. The above circuit is from (Grebenkemper 1987) and is … Continue reading Sontheimer coupler – transformer issues – an alternative design – FT37-43
Reviewing consistency of measured and model data, the first posting was based on an incorrect model parameter (aol), the article is now revised for the correct value, apologies. End Fed Half Wave matching transformer – 80-20m described a EFHW transformer design with taps for nominal 1:36, 49, and 64 impedance ratios. Keep in mind that … Continue reading End Fed Half Wave matching transformer – 80-20m – model and measurement
Sontheimer coupler – transformer issues discussed problems with the Sontheimer coupler in a recently published QRP transceiver ((tr)uSDX / trusdx), suggesting that the core loss in transformer T2 was excessive. This article presents an alternative design for the transformer for a coupler for a 5W transmitter. The above circuit is from (Grebenkemper 1987) and is … Continue reading Sontheimer coupler – transformer issues – an alternative design – FT23-43
One sees online discussions and videos where phase from a NanoVNA display is central to the subject, and more often than not, the use is quite confused. Let’s look at some examples. Example 1 A poster advising on how to measure inductance using a NanoVNA posted a .s1p file of his measurements of a SM … Continue reading NanoVNA phase confusion
This article is part of a series discussing inductors, their characteristics, and measurement, continuing from NanoVNA-H4 – inductor challenge – part 5. The previous articles have discussed these matters in the context of an air cored solenoid, this article moves on to inductors with a magnetic core. A magnetic core increases the flux Φ due … Continue reading NanoVNA-H4 – inductor challenge – part 6
Lots of online discussions on ferrite cored transformer losses might make you think that the core material is in a path in series with the transferred power and that it acts to some extent like an attenuator. That sort of thinking betrays a lack of understanding of how a transformer works. If you take a … Continue reading Transformers and flux density