Cross position load coil antenna for HF band plan

This is a theory type design antenna, but if the idea holds may provide some interesting results on the HF band plan. The principle is a four system load coil antenna where-by four 12uH load coils are used in parallel combination for the antenna design. The below diagram illustrates the point:

The feed point of the antenna design is connected to an auto ATU unit. It has come to my knowledge that a Mydel CG3000 will impedance match a full-wave antenna, be it long wire or an antenna with a full-wave impedance load.

Now much of the current antenna theory has an end feed full-wave length impedance as several thousand ohms in value, however, the inductive reactance of a long wire antenna of a full-wave length in design has an inductive reactance of around 560ohms. This brings things to a point of some interest, namely the fore-mentioned topic title of this article.

Now a Mydel CG3000 auto ATU according to the internet webpages, will impedance match a full wave length impedance, that is to say match a 12meter wire on the 10m band. Although a 12metre wire is a bit m ore than the 10m band full wave length, it is otherwise point made. The Mydel ATU unit could impedance match a 560ohm inductive reactance load of a full-wave long wire, or a load coil of the same inductance as the long wire.

With a metre of wire exhibiting an inductance of 300nH, a 12uH coil would otherwise be a 40metre length of wire, but here wound up as a load coil inductor. On the 10metre ham band, the 12uH load coil would present an inductive reactance of some 2240ohms, but with four of these load coils arranged into a configuration as illustrated in the above diagram, the equivalent inductance reactance would be one quarter of the value, i.e. thus 560 ohms.

Operating on Top Band, 160metres, the load coils 12uH value (40m of long wire) is equivalent to a quarter of a wave length on Top Band. A quarter wave length exhibits an impedance of some 140ohms, thus driving all four antennas in parallel would present an impedance of some 35ohms.

Operating the antenna design in theory would produce some interesting results. On transmit mode, the transmitter signal would be split four ways, in other words the 100Watts Tx signal would be split to 25Watts per load coil. However as each load coil on 10m band is the same as four wave lengths, the efficiency gain of the electromagnetic coupling to the ether as a four wavelengths, would multiply the Tx signal power on each load coil to four times the original value. The greater the electromagnetic coupling to the ether the better would be the signal output or signal reception. The hence is that each load coil on the 10m band would couple an equivalent 100Watts to the ether due to the 12uH coil coupling, equating perhaps to a 400Watts overall transmitter output.

On reception on the 10m band is even more interesting. Each coil as a four wave length would gather four times the signal, from the electromagnetic coupling of the 12uH load coil. A 1uV signal would then be a 4uV gathered signal, but as there are four load coils, the overall signal would add, thus perhaps providing a 16uV signal reception on the 10m band to a normal 1uV signal.

On the 160m band, Top Band, things are a little different. On transmit mode the 12uH load coil is equivalent to a quarter wave length, so are 25% efficient. As a result, out of the 100Watts, just 25Watts presented to each load coil, but only a quarter of the 25Watts would be coupled to the ether, thus 6·25Watts. However over four load coils, the overall transmitter signal would be the 25Watts.

On the reception side of things, the 12uH load coils when all four are added together, equate to a 160metre of long wire, in other words the four 12uH load coils equate to a full wave length 160m antenna design. The 1uV reception signal on Top Band would then be the 1uV signal into the radio antenna socket input.

Food for thought.