ANTENTOP- 01- 2015 # 019

Universal Beverage Antenna

Transformer of the Beverage Antenna

Transformer of the Beverage Antenna is one of the important parts of the antenna. Transformer should work at all frequency range of the antenna. Transformer should stand power going to the antenna. It is preferably use to transformer with insulated windings for any Beverage Antenna. Figure 4 shows Beverage Antenna with transformer with insulated windings. Such transformer provides electrical insulation the antenna from transceiver. It causes less noise from electrical interferences and provides additional protection of the transceiver from lightning discharge. However to make such transformer is not an easy task. Thereof I used unsymmetrical RF transformer 1:9.

Figure 5 shows schematic of classical unsymmetrical RF transformer 1:9. The transformer is winding by a triple wire onto a ferrite core. It may be a ferrite ring or ferrite rod. Transformer may contain 7- 15 turns.

Quantity of turns depends onto size and permeability of the ferrite core and frequency range of the antenna.

Figure 5 Schematic of Classical Unsymmetrical RF Transformer 1:9

Figure 4 Beverage Antenna with Transformer with Insulated Windings

My first attempt to make RF transformer was use a TV Yoke's ferrite ring for the transformer 1:9. Figure 6 shows the TV Yoke. I removed wires from the yoke. Then the ring was wrapped by black vinyl insulation tape. Unsymmetrical RF Transformer 1:9 was made according to the Figure 5. Transformer contained 8- turns of usual electrical wire. Figure 7 shows ready Unsymmetrical RF Transformer 1:9 on TV Yoke. The transformer was tested. At the beginning the transformer was tested with usual metal resistor in resistance 440 Ohm. Table 1 shows data for transformer made on Yoke Core loaded to Resistor 440 Ohm the measurements made by MFJ- 259B. Table 2 shows data for the transformer made on Yoke Core loaded to home brew Resistor 440 Ohm (shown at Figure 3) the measurements made by MFJ- 259B. The home brew resistor has some reactance that clearly seen from the two tables. MFJ- 259B does not indicates the character of the reactance (capacitance or inductive) so I used sign "@" at the reactance.

Figure 6 TV Yoke

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