copper Tube Loops
conditioning soft copper tubes are perfect for loop construction.
If you want to try a loop you must have an air variable
capacitor or a vacuum variable capacitor.
vacuum types are hard to find and expensive, but they
have high isolation figures (ideal for high power operation)
and can range from some Pico farads to hundreds of Pico
farads indicated to design a small magnetic loop that
can cover 10 meters to 80 meters.
high power operation you will need big spacing between
the plates of the air capacitor.
most common variable capacitors present high losses due
to the mechanical electric contact on the metal surfaces.
most recommended are the butterfly or the split stator
air variable capacitors.
not be disappointed with you have only the standard metal
air capacitors. I still use them on some projects despite
knowing all the performance compromise they can represent.
the “Magnetic Loop Links”, you can have all
the theoretical information to design your loop. My personal
proposal is give to the reader practical ideas for the
On the following photos
can be seen two soft copper small magnetic loops, both
of them are made on 3/4 inches soft copper tubes.
bigger has 91 CMS in diameter and measures 2.89 CMS from
The excited loop is made on coaxial cable and measures
2.89 CMS divided by 5.
The capacitor is 10 Pico farads to 80 Pico farads split
smaller one has 66 CMS in diameter and measures 2.08 CMS
from each extreme, and is closed with a standard 12 to
100 Pico farads capacitor.
The excited loop follows the 1/5 of the main loop measures.
Soft copper magnetic
66 CMS diameter
1.9 CMS soft tube
Standard 12/100 capacitor
Coupling made with two
glued plastic knobs
over de cable.
stator 10 / 80 Pico farads.
knob and excited loop.
the loop to the capacitor.
AHD ALEX (Alexandre Grimberg).