The September 2020 ARRL VHF Contest
was coming and for this party I decided to make an antenna for
the 6 meters band. Of course, it is not wise for me to install
only single-band antenna for the 6- meter band, therefore, using
the my lovely simulating antenna program MMANA I did simulation
for antenna that could operate at 6 and 20 meters, and even at
15 meters with a slightly high SWR. It was a dipole with two loading
coils and additional wires for 15 meters.
I only need to go to Home Depot
to buy tubes for loading coils and some hardware stuff for installation
of the antenna. But before the trip a hurricane is happened...
Storm wind and 200- mm rain with hails run through Niagara Falls.
This hurricane destroyed my cucumber and tomatoes and pelted backyard
with branches of the trees.
It is not so bad anyway the branches
were prepared for fireplace for winter time. Then, two weeks later,
one more almost the same hurricane (but not so much rain and no
hails) run across the city. During the hurricane I went to backyard
and realize that the new antenna will be in the center of the
hurricane wind. Winter is going ahead with other strong wind and
ice rain. So I decided install something simple and wind- resistant.
Most simple antenna it is a Zeppelin antenna in form of one line.
However it is one band antenna. So I decided install a Zeppelin
antenna for the 6- meter band.
Figure 1 shows design of classical Zeppelin antenna for the 6- meter band. It
is half wave antenna that matched with 50- Ohm coaxial cable through
a quarter- wave length of two wire line. RF- choke is installed
at the feeding terminals of the antenna. Most simple design of
the RF- choke it is several ferrite rings on the coaxial cable.
Before installation of the Zepp antenna in the backyard I decided to test the antenna
inside my house. Below there is shown several steps for doing
of the antenna. I start with RF- choke. RF choke for the antenna
consist of seven ferrite tubes in 35-mm length and 17- mm OD.
I do not know parameters of the ferrite tubes I bought it at a
ham flea market several years ago. Photo 1 shows the tubes on the coaxial cable.
Then the ferrite tubes were wrapped with electrical tape. Photo 2
shows the RF- choke.
quarter- wave transformer was made from 450- Om ladder line that
I bought at MFJ website. For antenna wire I have used a green
wire (this wire used for GROUND in electrical connection). Copper
core of the wire had 1.5- mm diameter and OD of the wire was 2.2-
Photo 1 Ferrite Tubes on the Coaxial Cable