A Four- Bands Off-Center Dipole Antenna (for 80- 40- 20- and 10- meter
Bands) is well known among radio amateurs. However, the antenna
cold be tuned to the fifth band (15- meter) just by adding of
two 2 insulators and two closed stub with electrical length lambda/4
at the 15- meter Band. Figure 1
shows the antenna.
The parts of the antenna, that are located before
the insulators (from feeding terminals), work on the 15- meter
Band. The lambda/4 closed stubs cut off from the antenna the parts
of the antenna located after insulators on the 15- meter Band.
At the other bands all parts of the antenna are worked because the stubs
included in the overall antenna length.
The lambda/4 closed stubs made from a ribbon two wire ladder line. Length
each of the stub is 4.85- meter. One end of the stub closed another
end of the
Radio and TV-news,
stub soldered to the antenna.
Length of the wires between antenna and the stub is 15- cm. Stub
should be tuned to the 15- meter Band (for example with help of
a DIP-Meter) before the installation into the antenna.
Both stubs should be tuned onto the same frequency.
The antenna worked great at the all five bands.