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ANTENTOP- 01- 2016 # 020

Experimenters with Non Snap Ferrite Cylinder Bead RF Chokes

 

 

Second experimental transformer was made with two Cylinder Ferrite RF Chokes. Figure 6 shows schematic of the transformer. It was classical RF Transformer where one turn is primary and second turn is the secondary winding. Then the transformer was tested. Primary winding was connected to MFJ- 259B. Secondary winding was loaded on to 51- Ohm resistor. Figure 7 shows the transformer loaded to 51-Ohm resistor. Table 2 shows data obtained for the two Ferrite RF Chokes transformer.

 

As you can see from the table the transformer had parameters better the one cylinder transformer. Certainly the transformer may be used for receiving purposes. I tested the transformer with my transceiver IC- 718 and receiver Hallicrafters S- 85. Transformer worked good up to 80- meter Band. Then I observed some dropping of receiving signals. However I could compensate it with adding RF- gain at transceiver and receiver where the transformer successfully worked at MW-Band. Transformer was tested with IC-718 in transmitting mode, 15- wt.  SWR showed by IC- 718 is close to SWR showed by MFJ- 259B.

 

 

Figure 7 RF Transformer on Two Cylinder Ferrite RF Chokes loaded to 51- Ohm Resistor

 

Conclusion:  The transformer may be used as Insulated Transformer for Receiver at the HF and MW. The transformer may be used for some purposes (like insulation transformer installed on antenna and then matched with coaxial cable) at transmission mode at the 40- 10 meter Bands.

 

 

Figure 6 RF Schematic for RF Transformer Made on Two Cylinder Ferrite RF Chokes

  

 

Table 2 Two Cylinder Ferrite RF Chokes loaded to 51- Ohm Resistor. Data obtained with MFJ- 259B and IC-718

 

Band

160

80

40

30

20

17

15

12

10

Z by MFJ-259B

5@j18

13@j27

29@j28

33@j26

35@30

37@j33

39@j38

40@41

40@48

SWR by MFJ-259B

8.2

4.3

2.3

2.1

2.1

2.1

2.2

2.3

2.6

SWR by

IC-718

-

-

2.7

2.0

2.0

1.8

2.0

2.1

2.5

 

 

 

 

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April 9, 2016 22:50

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