antentopSince2 July

** PLEASE DESCRIBE THIS IMAGE **
** PLEASE DESCRIBE THIS IMAGE **

 

 

 

 

Antentop is FREE e-magazine devoted to Antennas and Amateur Radio an

Special page devoted to

Experimenters

with

Non Snap Ferrite Cylinder

Bead RF Chokes

Custom Search

 

ANTENTOP- 01- 2016 # 020

Experimenters with Non Snap Ferrite Cylinder Bead RF Chokes

 

Well, but what can I do with old Ferrite "Bead" RF Chokes. I just cut of the chokes together with wires from scrapped devices. To remove the ferrite tube from the chokes takes time and tools. So I decided make some experimenters with the chokes without disassembly those ones.

 

I find in my junk box four identical Ferrite "Bead" RF Chokes. Each choke has length 36- mm with outer diameter 18- mm. Two wires cable went through the choke. The wire was marked as diameter 18- AWG and 300- V voltage. My idea was to create a kind of RF transformer with the chokes.

 

First experimental transformer was made according Figure 4. It was classical RF Transformer where one turn is primary and second turn is the secondary winding. Then transformer was tested. Primary winding was connected to MFJ- 259B. Secondary winding was loaded on to 51- Ohm resistor.

Figure 5 shows the transformer loaded to 51-Ohm resistor. Table 1 shows data obtained for the one Ferrite RF Choke. As you can see from the table 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 40- 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.

 

Conclusion: The transformer may be used as Insulated Transformer for Receiver at the HF and MW.

 

Figure 3 Snap Ferrite Choke on the Coaxial Cable

 

 

Table 1 One Cylinder Ferrite RF Choke loaded to 51- Ohm Resistor. Data obtained with MFJ- 259B

 

Band

160

80

40

30

20

17

15

12

10

Z

2@j12

6@j19

17@j27

23@j28

27@31

31@j35

34@j38

39@43

41@j46

SWR

14.0

9.0

3.5

2.8

2.5

2.5

2.4

2.4

2.5

 

 

 

Figure 4 RF Schematic for Transformer on one Ferrite RF Choke

 

Figure 5 RF Transformer on one Ferrite RF Choke loaded to 51- Ohm Resistor

 

 

www.antentop.org

Page- 77

 

76 77 78 79 80 81

 


 

 

Just for Fun:

Map IP Address
Powered byIP2Location.com

Thanks for your time!

Last Updated:

April 9, 2016 20:15

** PLEASE DESCRIBE THIS IMAGE **

** PLEASE DESCRIBE THIS IMAGE **

2003entop