Magnetic Loop for the 2m band
Materials and description
The whole choice is copper. This loop is made of 50cm of 4mm "soft"
The capacitor of two 1mm circular plates with about 3cm diameter
torch-brazed to the loop conductor. The coupling loop is made of 1mm
wire and held by a luster terminal. Tuning is done by bending the loop
to in- or decrease the capacitor plate's distance.
The whole thing is than strapped to a bar of plastics with a tiny whole
in it's center of mass to be skewered to my fiberglass telescopic mast.
Meanwhile I built a second magnetic loop for this band, made of
an old used UHV (ultra high vacuum) ring gasket and a small tube
The gasket is made of 1mm copper with an outer diameter of 120mm and an
inner diameter of 100mm. The capacitor is connected by screws and the
loop by a luster terminal screwed on the gasket. A photograph is taken,
but not yet available, sri...
The main concern with copper is, that it corrodes. Remember, skin
Some finish should be applied to protect the conductor's surface.
Such kind of omnidirectional antenna gives the possibility to be QRV
horizontal polarisation, as commonly used for the CW and SSB section of
the 2m band. This actual design shows a 1.3:1 bandwidth of about
centered to 144.200MHz. The SWR on the lower end of the CW section
allows transmitting. The aerial gave good results on the local rag chew
at 144.350MHz (using 10W pep) with the clear advantage of the
diagram of a "lying" magnetic loop.
Do not believe people telling you that this kind of antenna does not
work for higher frequencies. It will not make you QRV from the
but held up in the air, to the same hight you would lift a beam to, it
performs really satisfatory.