HOME  |  ARTICLESBAND CONDITIONS  |  EQUIPMENT  |  LINK  | MAIL   |  OPERATIONAL  |  PROJECTS

6:1 VOLTAGE BALUN

6:1 Voltage balun. Install July 2016.


Requiring a balun to feed a balanced antenna from an un-balanced load with a impedance step up from 50ohms to 300ohms, a 1:6 Voltage balun design using two L15 ferrite toroid cores was selected.

 

 

Construction

 

The 1:6 voltage balun has 5 turns wound evenly spaced around the L15 ferrite toroid core with the five individual windings wound close together. The toroidal core was rapped in an overlapping layer pink heavy duty Teflon plumbers tape to protect the enamelled copper wire from insulation puncture from abrasion with the toroid core.

 

Figure 1 Schematic of the 1:6 Voltage balun

Figure 1 Schematic of the 1:6 Voltage balun  

 

Figure 2  Wiring of the 1:6 Voltage balun

Figure 2  Wiring of the  1:6 Voltage balun  

 

 

Parts list.

  • L15 ferrite toroid core.

  • About  500mm of 1.25mm Enamelled copper wire.

  • SO-239 UHF chassis mount connector

 

Photo 1 6:1 Voltage balun assembled. 

Photo 1 1:6 Voltage balun assembled

 

Photo 2 1:6 Voltage balun assembled in weatherproof enclosure

 

Photo 3 1:6 Voltage balun assembled in weatherproof enclosure

  

The evaluation of the efficiency of the balun over the desired bandwidth (0.5 - 60MHz) was carried out by testing the impedance that could be seen from unbalanced side to a resistive load applied to the balanced side using an antenna analyser. The below antenna analyser plot views a 300ohm resistive load attached to the balanced side of the balun and measured at a nominal impedance of 50ohms presented as anticipated an approximate 50ohm load to the analyser and produced about a 1:1 SWR

The performance of the balun from 0.5MHz to about 30MHz is good and shows little reactance, however there is a gradual rise in reactance above 30MHz along with a gradual rise in the SWR. Despite this rise in reactance and SWR the balun should still perform well within the 50 54MHz amateur band.

 

Figure 3  AIM 4170C antenna analyser plot viewing a 300ohm resistive load through the voltage balun. Note the 300ohm resistor appears as 50ohms due to the 6:1 balun ratio resulting in an ideal SWR of 1:1.

Figure 3  AIM 4170C antenna analyser plot viewing a 300ohm resistive load through the voltage balun. Note the 300ohm resistor appears as 50ohms due to the 6:1 balun ratio resulting in an ideal SWR of 1:1. 

AIM 4170C antenna analyser explanation;

SWR

Standing Wave Ratio.

Zmag

Total Impedance.

Theta

Phase angle between voltage and current.

   

Also see other baluns and ununs:

1:1 Choking balun Choking balun for lower HF and MF bands. (1.8MHz - 10MHz) T250-26 Powdered Iron Toroid Core..

1:1 Guanella current balun 1:1 Guanella current balun (1.8 - 30MHz) L15 ferrite toroid core.

1:4 Guanella current balun 1:4 Guanella current balun (1.8 - 30MHz) L15 ferrite toroid core.

1:1 Ruthroff voltage balun, 1:1 Ruthroff voltage balun (1.8 - 30MHz) T-200-2 powdered iron toroid core.

4:1 Ruthroff voltage balun  4:1 Ruthroff voltage balun (1.8 - 30MHz) T-200-2 powdered iron toroid core.

6:1 Ruthroff voltage balun  6:1 Ruthroff voltage balun (1.8 - 30MHz) L15 ferrite toroid core.

1:9 voltage unun_v1  9:1 voltage unun (1.8 - 30MHz) T-200-2 powdered iron toroid core. Version 1 

1:9 voltage unun_v2  9:1 voltage unun (1.8 - 30MHz) L15 ferrite toroid core. Version 2

 

TOP OF PAGE

Page last revised 13 October 2016  
 

ACTIVITIES | ARTICLES | EQUIPMENT | HOMELINK | MAIL | PROJECTS

Web design by Peter Miles

All content may be used for unlimited distribution with credits.

This site has been designed to cater for 800 x 600 resolution.
Site is best viewed with Internet Explorer 5.5 or Netscape 6 or higher.