Dear Peter, LF Group, Reflecting on this, there are some quite good reasons to use a 50ohm impedance level for coupling bits of the system, even at LF. This is down to the fact that the resistive par
Dear Bryan, LF Group, More or less - but the point is that, for any particular antenna, coil diameter and winding pitch, there are only one or sometimes 2 combinations of TX and antenna tapping point
Surely if antenna impedance is lo and amplifier higher then the antenna needs to be tapped down from the top and the amplifier final tapped "up" from there ? If moving the antenna tap detunes the the
I have been doing some investigation into the design of tapped loading coils for LF antennas � specifically, where to put the tap for the TX connection to achieve matching to 50 ohms. As far as I c
Jim, I knew about the mutual coupling between the turns, but never stopped to think about the effect on the upper limit of impedance match. Interesting! Please send me the file. John Andrews, W1TAG T
Dear John, LF Group, This design approach would work fine if there was no or negligible coupling between the portion of the coil "below" the tap, and the portion "above", i.e. if the loading coil was
Jim, I have always viewed tapped loading coils as a high-pass "L" network, where the upper part of the coil leaves a small amount of capacitive reactance, representing the "C" in the network. The shu
Dear LF Group, I have been doing some investigation into the design of tapped loading coils for LF antennas – specifically, where to put the tap for the TX connection to achieve matching to 50
