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1:6 VOLTAGE BALUN
1:6 Voltage balun. Install July 2016.
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 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
2 Wiring of the 1:6 Voltage balun.
Note
this drawing shows winding connections and not the number of turns
required. See article for details.
Parts
list.
-
L15
ferrite toroid core.
-
About
500mm of 1.25mm Enamelled copper wire.
-
SO-239
UHF chassis mount connector
-
1.25mm
Enamelled copper wire.
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.
AIM 4170C antenna analyser explanation;
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SWR
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Standing Wave Ratio.
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Zmag
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Total Impedance.
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Theta
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Phase angle between voltage and current.
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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 19 October, 2024
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