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1:6 VOLTAGE BALUN -
VERSION 2
1:6 voltage balun using a FT140-43 Ferrite Toroid Core for 0.5MHz to 30MHz. Completed January 2022.
Requiring
a balun to feed a balanced antenna from an un-balanced line with a
impedance step up from 50ohms to 300ohms, a 1:6 Voltage
balun design using a FT140-43
Ferrite Toroid Core
was selected.
Construction
The
1:6 voltage balun has 6 x 2 and 4 X 2 turns 0.5mm2 hook-up wire
wound evenly spaced around the FT140-43 Ferrite Toroid Core. See Figure 2 and
Photo 1 for details.
Figure 1 Schematic of the 1:6 Voltage balun
Figure
2 Wiring of the 1:6 Voltage balun.
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Type
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Voltage
Balun
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Ratio
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1:6
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Frequency
Range
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0.5
~ 30MHz
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Core
Used
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FT140-43 Ferrite Toroid Core
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Number
of turns
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6
x 2 and 4 X 2
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SWR
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Low
1:1.2 (2.5MHz) High
1:1.7 (30.0MHz)
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PEP
Power Handling.
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Approximately
100W
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Photo 1 1:6 Voltage balun assembled.
The
evaluation of the efficiency of the balun over the desired bandwidth
(1.0 - 30MHz) 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
AIM 4170C antenna
analyser. The below antenna analyser graph shows a 300ohm resistive
load attached to the balanced side of the balun and measured at a
nominal impedance of 50ohms that should presented an approximate
50ohm load to the analyser and produced about a 1:1 SWR
The
performance of the balun from 0.5MHz to 30MHz is good and shows
little reactance, however there is a gradual rise in reactance above
10MHz along with a gradual rise in the SWR. Despite this rise in
reactance and SWR the balun should still perform well.
Figure
3 SWR.
AIM 4170C antenna analyser data graph viewing a 300ohm resistive load through the voltage balun from 0.1MHz to 30MHz. Note the 300ohm resistor appears as 50ohms due to the 1:6 balun ratio resulting in an ideal SWR of 1:1. The SWR is shown to be consistently low for all Amateur radio bands with a high of just 1:1.7 for the 10m band.
Figure
4
Impedance The AIM 4170C antenna analyser data graph viewing a 300ohm resistive load through the voltage balun from 0.1MHz to 30MHz. Note the 300ohm resistor should ideally appears as 50ohms due to the 1:6 balun ratio.
Figure
5 Impedance
(R & X). AIM
4170C antenna analyser data
graph viewing a 300ohm resistive load through the voltage
balun from 0.1MHz to 30MHz. Note the 450ohm resistor should ideally
appears as 50ohms due to the 1:6 balun ratio. The impedance should
ideally be R (Resistance) at 50 ohms and X (Reactance) near zero
ohms. The Purple line shows the resistance component in ohms of the
Impedance and the Orange line shows the reactive component in ohms
of the Impedance, the + values for the reactance represent Inductive
reactance and the negative values represent the Capacitive
reactance.
Conclusion
The
Version 2 1:6 voltage balun using
a FT140-43
Ferrite Toroid Core represents a very efficient balun for a
frequency range from 0.5MHz to 30MHz at a power level of 100W PEP.
Power
Handling
For
Summary of suitable ferrite cores and core types for a frequency range
of 100 kHz to 50 MHz for power levels of 50W, 100W, and 500W
continuous and SSB. It assumes good thermal management and proper
balun design. See: Power
- Ferrite Core Design
Also
see other baluns and ununs:
BALUN
1:1 CHOKE & 1:4 BALUN HF
ladder feed-line to coaxial cable combination choke and 1:4 balun.
(0.1MHz - 30MHz).
BALUN 1:1
CHOKING Choking balun for
lower HF and MF bands. (200kHz - 10MHz).
CHOKING
1:1 BALUN - HF BANDS Reisert choking balun.
(1.0MHz - 30MHz). FT240-43 Ferrite Toroid Core.
CHOKING
1:1 BALUN - HF BANDS Reisert choking balun (1.5MHz - 30MHz). FT140-43
Ferrite Toroid Core.
CHOKING
1:1 BALUN - LOW VHF BAND Choking balun.
(10MHz - 60MHz). FT140-43 Ferrite Toroid Core.
BALUN
1:1 CURRENT 1:1 Guanella Current balun using a L15
ferrite core (1.8 - 30MHz).
BALUN
1:4 CURRENT 1:4 Guanella Current balun using a L15
ferrite core (1.8 - 30MHz).
BALUN
1:4 SINGLE CORE CURRENT 1:4 Guanella Current Balun, single FT240-43
ferrite toroid cores. (0.3MHz - 30MHz).
BALUN 1:1
VOLTAGE 1:1 Ruthroff voltage balun using a T-200-2 powdered iron
toroid core (1.8 - 30MHz).
BALUN 4:1
VOLTAGE 4:1 Ruthroff voltage balun using a T-200-2 powdered iron
toroid core (1.8 - 30MHz).
BALUN 6:1
VOLTAGE - VERSION 1 6:1 Voltage balun using a L15 ferrite toroid core (1.8 - 30MHz).
BALUN 6:1
VOLTAGE - VERSION 2 6:1 Voltage balun using a FT140-43 Ferrite
Toroid Core (1.8 - 30MHz)
BALUN 9:1
VOLTAGE - VERSION 1 9:1 Voltage balun using a L15 ferrite toroid core (1.8 - 30MHz).
BALUN 9:1
VOLTAGE - VERSION 2 9:1 Voltage balun using a FT140-43 Ferrite
Toroid Core (0.5 - 60MHz).
UNUN 9:1
VOLTAGE 9:1 voltage unun
using a T-200-2 powdered iron toroid core (1.8 - 30MHz).
UNUN 9:1
VOLTAGE VERSION 2 9:1 voltage unun using a L15 ferrite core (1.8
- 30MHz).
UNUN 9:1
VOLTAGE VERSION 3 9:1 voltage unun using a FT140-43 ferrite core
(0.5 - 60MHz).
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last revised 12 March 2024
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