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ANTENTOP- 01- 2015 # 019

Universal Beverage Antenna

 

 

Table 1 and Table 2 show that the transformer works well at 160- and 80- meter Bands, fair at 40- and 20- meter Bands and bad beginning from 17- meter Band. Of course it is possible play with quantity of the turns but anyway it should be difficult to make a real broadband transformer that covers 160- 10- meter Bands. So I gave up attempt to use RF transformer on TV Yoke core at my Beverage Antenna.

 

In my parts box there was a symmetrical Balun from LDG. Figure 8 shows the Balun. Some time ago I experimented with the Balun. However for that time it just took place in the box waiting for a new application. Time is come. The Balun had strong plastic cabinet with socket SO- 239 on it from one side and two terminals (for antenna and for ground) at another side.

 

Figure 7 Unsymmetrical RF Transformer 1:9 on TV Yoke

 

Table 1

Transformer made on Yoke Core. Loaded on to single resistor 440 Ohm. Measurement by MFJ- 259B

 

Band

160

80

40

30

20

17

15

12

10

Z

48@j5

45@j4

35@j1.4

27@j1

19@j11

13@j29

11@j40

9@j54

6@j69

SWR

1.1

1.1

1.4

1.8

2.5

4.3

6.7

9.1

12.4

 

 

 

Table 2

Transformer made on Yoke Core. Loaded on to eleven 4.7-kOm resistors switched to bridge (440 Ohm overall). Measurement by MFJ- 259B

 

Band

160

80

40

30

20

17

15

12

10

Z

49@j4

44@j6

31@j3

23@j2

15@j17

10@j33

10@j41

6@j61

5@j70

SWR

1.0

1.1

1.5

2.0

3.0

5.7

7.9

11.7

14.4

 

 

A ferrite ring was used on the Balun. The sizes of the ring were suite for transformer 1:9 that could work at 100- Wtts RF power going through. It was not hard reworked the Balun to unsymmetrical RF transformer 1:9. Additional wire in Teflon insulation was coiled between turns of the Balun. Then the wires were connected according to Figure 5. Figure 9 shows the unsymmetrical RF transformer 1:9. The transformer was tested. Table 3 shows data for the transformer loaded to Resistor 440 Ohm the measurements made by MFJ- 259B.

 

 

Figure 8 Balun RBA- 1:1 from LDG

 

Table 4 shows data for the transformer loaded to  home brew Resistor 440 Ohm (shown at Figure 3) the measurements made by MFJ- 259B. As you can see the transformer works well from 160- to 10- meter band. It is possible play with quantity of the turns to move low SWR up or down inside the 160- 10- meter Band. However, I did not do it and leaved things like this.

 

 

Figure 9 Unsymmetrical RF transformer 1:9 on the Base of Balun RBA- 1:1

 

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