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MARCONI 'L' ANTENNA CONFIGURATION
Adapting
the
main
HF Doublet Antenna as ‘L’ Antenna is achieved by simple
connecting to one side of the ladder line in the shack directly to
the T-Match antenna tuner.
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CONFIGURATIONS >
The
main HF antenna is an All Band Doublet fed with ladder line and
matched with a T-Match antenna tuner including a 1:4 current balun
giving access to all HF band including the 160m band. With a view to
get better performance particularly on lower frequency bands this
antenna was reconfigured as a type of ‘L’ Antenna by connecting
to one side of the ladder line in the shack directly to the T-Match
antenna tuner
This antenna requires a counterpoise to work well and this will achieved
at least initially by using the galvanized building roof to serve
this purpose.
Fig
1
Multi-band
dipole antenna configured as a type of 'L"
Antenna. Note left side of the antenna and feed line not connected.
Basic All Band Dipole
Arrangement
(1) Inverted 'V'
Dipole 42Mtr total length
(2) 450 Ohm Ladder
Line 8Mtr length.
(3) Junction box
(Ladder line - twin heliax interface)
(4)
Twin heliax 3.5Mtr
length.
(5)
Twin SO259 bulkhead sockets
(6) T-Match Tuner.
See T-Match
Tuner
(7) VSWR Meter.
(8) HF Transceiver.
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| Photo#1 Junction box (Ladder line - twin heliax interface) |
Photo#2 Junction box (Ladder line - twin heliax interface)
assembly |
Photo#3
Twin
SO259 bulkhead sockets and Ground connection. |
Antenna
Modelling with MMANA-GAL
Fig 2 All Band Doublet modelled with
MMANA-GAL
in the normal configuration at 1.825MHz.
Fig 3 All
Band Doublet re-configured to a 'L' Antenna and modelled with MMANA-GAL
at 1.825MHz.
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last revised 05 May, 2025
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