Brief
story:
Between 10 to 12 years old I was playing with 1N34 germanium
diode AM radios.
At 13
my best Bar Mitzvah gift, a Playboy six transistors radio
was converted into an AM transmitter connected to the television
antenna.
At 14
my grandmother brought me from U.S. a Lafayette regenerative
CB handy talkie.
At 15
the handy talkie 14 channel crystal jump to a 6C4 oscillator
tube to drive a 6L6 on my first 30 watts transmitter.
When I was 20 years old
One
of mine early 10 meters QRP pedestrian HF pack
At 20
my first radio amateur license and my first HF pedestrian
operation with CB radios converted to 10 meters band adapted
with rechargeable battery cases and telescopic whips.
After
three decades of soldering iron burns and many outdoor radio
experiences I bought the FT 817, the almost perfect radio
for HF Pack portable operation.
The
Magnetic Loop Antenna
PY1 ZFP
Flavio Pohlmann, came to my shack to see the new FT 817 and
brings me a 144 MHz version of a Magnetic Loop. I became fascinated
with the antenna characteristics. Two hours latter I have
my own magnetic loop working from 24 MHz to 60 MHz.
After
that I have build circa 30 different magnetic loop models
using the most common to the most exotic materials.
On this
site I will present practical solutions that will help anybody
to build and have amazing experiences with the magnetic loops
associated to QRP HF Pack.
The magnetic
loops presented are low power devices (10 watts maximum) having
in mind that all of them are using low isolation tuning capacitors.
The best
variable capacitors due to the lowest resistive losses are
the split and the butterfly ones, but if you have in hands
standard air variable capacitors you can perfectly use them.
For greatest
power (100 watts) are recommended vacuum type capacitors or
high isolation variable air capacitors.
Be careful,
the amount of RF energy concentrated on a loop antenna is
very high, so if you intent to run high power, never touch
it and avoid to be near the antenna
At the
end of the page I will supply the readers with loop antennas
links for sites that are useful for practical and theoretical
aspects on the loop construction.
I must
confidence to the readers that I am achieving more fun in
QRP HF Pack operation with the loop antennas on the last three
years then on all my radio hobby life.
I have
collected on my log around 400 Dxs running 5 watts on my loop
antennas.
The loop
antenna is a plug and play device, ready to work. To be on
the air, I lift a Velcro band that keeps 130 CMS of coaxial
cable accommodated on “S” shape over the antenna
handle and plug the connector on the radio back.
All this
HF Pack excitement can be find on the www.hfpack.com
a site idealized by KQ6XA BONNIE CRISTAL where all of us can
share our own experiences and learn even more with Bonnie
and the HF Pack staff technical suggestions.
The
magnetic loop passion
Finally
considering my acquired experience over this last three years
building and field testing magnetic loop antennas, I am considering
the possibility to anticipate my business retirement and start
a hand made production on magnetic loops.
To
make this project come trough I will need to have the feedback
from the page readers to my e-mail “py1ahd@ig.com.br“
telling me what is the magnetic loop model each one likes
most and what will be the right value in U.S. dollars for
it.
Thanks
to all.
Check
this page frequently for my latest magnetic loop designs.
PY1 AHD
ALEX (Alexandre Grimberg).
