At PD7MAA’s BN43-202 matching transformer for an EFHW I gave an estimate of the core loss in PD7MAA’s transformer.
This article reports measurement of a prototype built to his design.
Above is PD7MAA’s graphic for his transformer. It is a little confusing as an 11t wind will start and finish with ends as the blue wind, so the red winding must have and odd number of half turns which suggests the windings are actually 1t and 5.5t (pity he did not show a picture of the real transformer).
PD7MAA gives some measurements for his transformer with a 3300Ω load, but he does not give loss measurements. This experiment is to replicate his configuration, measure the loss and compare it to the estimate given at PD7MAA’s BN43-202 matching transformer for an EFHW.
The prototype uses 1t primary and 5.5t secondary. The secondary load is a 3300Ω resistor in series with the VNA 50Ω input port.
Above is a screen shot of a sweep from 6 to 8MHz. The key data is that shown for the marker at 7.1MHz. Continue reading PD7MAA’s BN43-202 matching transformer for an EFHW – measurement of a prototype