LA6NCA, Larvik, Norway
MAGNETIC LOOP ANTENNA
MAGNETIC LOOP
No. 1
My first magnetic loop
was designed for more than 10 years ago.
25 mm Cu. tube was used. Diameter was 60 cm.
Frequency range: 14 MHz to 37 MHz.
MAGNETIC LOOP No. 2
3.5 MHz - 7.5
MHz
160cm x 120cm
The antenna is tested in the field.
LA6NCA
Loop no. 2 was a
car mount loop.
Size: 160 cm x 120 cm.
Frequency range: 3.5 to 7.5 MHz.
Two loops of 1x10mm Cu was used.
The capacitor is mounted on the top of the loop, and is actuated
by a motor.
Test results are very good.
For communications from 20 to 200 km is this small loop better or
as good as a full size field mounted dipole.
An HF whip antenna
is also mounted on the car.
The magnetic loop is fare better than the whip antenna.
Har utført en mengde tester på denne med meget bra resultat.
Spesielt egner denne antennen seg til HF samband på korte
avstander.
Korte avstander menes her 10 km - 150 km. Dette er ofte meget
vanskelig
pga. refleksjonsvinkelen blir meget bratt.
På disse avstandene fungerte loopen bedre en en full dipol i 15
meters høyde.
Frekvensene som ble benyttet var i frekvensområdet 3 MHz - 5
MHz.
Dette er en antenne som virker betraktelig bedre en de vanlige
stangantennene
som benyttes på mobile radiostasjoner. Brukere kan være
forsvar, FN, humanitære
organisasjoner mm.
MAGNETIC LOOP No. 3
Dette er en bærbar magnetisk loop med
frekvensområde 3 til 10 MHz.
Denne antennen kan pakkes ned i en liten veske.
MAGNETIC LOOP No. 4
14 MHz - 30 MHz
80cm x 80cm
Motor and capacitor.
This is a magnetic loop with a frequency range from 14.0 to
30.0 MHz
Size is 80 cm x 80 cm.
Material is 20 mm round aluminium tube and 20 mm x 40 mm square
aluminium tube.
Capacitor plates are mounted directly at the loop tube.
Simulated data:
14.3 MHz: - 5.7 dBd, SWR 2 - 20 KHz, 47 pF
21.3MHz: - 1.9 dBd, SWR 2 - 33 KHz, 19 pF
28.5MHz: - 0.7 dBd, SWR 2 - 94 KHz, 9pF
Dette er en magnetisk loop med
frekvensområde 14 MHz - 30 MHz.
Størrelsen er kun 80cm x 80cm.
Materialene er 20 mm aluminiumrør og 20mm x 40mm
firkantaluminium.
Rørene er poppet sammen.
Kondensatoren er laget av rette plater som er poppet direkte til
rørene.
En motor skrur en plate opp og ned slik at det dannes to serielle
kondensatorer
med økende eller minkende verdi. Dette gir en meget god
kondensator med lite tap.
Følgende data er simulert for denne antennen:
14.3 MHz: - 5.7 dBd, SWR 2 - 20 KHz, 47 pF
21.3MHz: - 1.9 dBd, SWR 2 - 33 KHz, 19 pF
28.5MHz: - 0.7 dBd, SWR 2 - 94 KHz, 9pF
Tabellen viser Frekvens, virkningsgrad, båndbredde og
kondensator.
MAGNETIC LOOP No. 5
145 MHz
10cm x 10cm
This is an experimental
loop, and has not any practical use.
Loop antenna can be tested out in a small variant with a high
frequency.
Test results can be scaled in size and frequency.
MAGNETIC LOOP No. 6
3.5 MHz - 7.5
MHz
150cm x 150cm
This loop was
designed in spring 2002, and tested in my holyday in Norway and
Denmark.
Test result is very good. Communications with most of Europe is
not difficult with this antenna.
The antennas
have two loops. Capacitor is mounted at bottom of the loop.
Loop one is made of aluminium tube, and loop two is made of RG213
cable.
Antenna is here ready for driving.
We are here testing out the loop antenna on the car and a dipole
antenna in the trees.
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Magnetic loop capacitor. A high-pressure
water-cutting machine has cut the capacitor plates.
Not ready. More info later.
LINKER
AA5TB ------http://www.aa5tb.com/loop.html
G4KKI, Bill---http://homepage.ntlworld.com/g4kki.william/radio.html
PA3HBB ---- http://www.qsl.net/pa3hbb/magloop2.htm
ON4CEQ ---- http://www.qsl.net/mnqrp/Loop/Mag_Loops.htm
Helge Fykse
email: mail
