Test of the antenna: Noise
was reduced to 3- 5 scale marks at the S- meter compare to resonance
antenna (antenna that was matched with FT857D with the help of
resonance ATU). Signals from ham stations also drop down when
the aperiodic antenna was used but I could hear the signals better
compare to noisy resonance antenna. SWR for the aperiodic antenna
is 1.0:1.0 from 1.5- MHz to 450- MHz band. When I tested the aperiodic
antenna I as usual could work with any ham station that I heard
in the Air.
Then I compared the aperiodic and resonance
antenna at the 7- MHz band.
I tuned my 14- meters wire in the resonance
at 7- MHz with help of a shortening capacitor. As a result I got
a wire that could be with simple toggle switch turn on or to resonance
antenna (shortening capacitor) or to aperiodic antenna (dummy
load 50- Ohm in bridge with the wire. I heard the Air and compared
receiving of the weak ham stations using resonance and aperiodic
antenna. The reception was almost the same with the both antennas.
However, with the aperiodic antenna the noise was low down that
acted like improving of the performance of the aperiodic antenna.
Aperiodic vertical antenna
data obtained from the test. I have got 59+5 from RW4CN (distance
1000 km) with the resonance antenna and 58- 59 with the aperiodic
one. I have got 59+10 from RA6FC (distance 3 km) with the resonance
antenna and 59 with the aperiodic one.
Some data obtained from the test. I
have got 59+5 from RW4CN (distance 1000 km) with the resonance
antenna and 58- 59 with the aperiodic one. I have got 59+10 from
RA6FC (distance 3 km) with the resonance antenna and 59 with the
aperiodic one. Aperiodic antenna loses to the resonance to transmitting
but gives good reception. My antenna has length in 14- meters
so the antenna works well from 7- MHz and higher (I heard and
could work with different DX- Station and could open at 145/430-
MHz almost all local repiters) but does
not work well at 3.6 and 1.9- MHz band.
The aperiodic antenna
may be used as the main, RX or emergency antenna. You may convert
any vertical or dipole antennas to the aperiodic ones. I believe
that at good placement of the vertical or dipole antenna you should
get good performance in the Air.
Figure 3 shows aperiodic vertical antenna, Figure 4 shows aperiodic dipole
HF- Wide Band Antenna with Transformer
I decided improve
the performance of my aperiodic antenna at the HF- Bands. To get
this improvement I added an RF transformer 1:9. Figure 5 shows the design of the
improved antenna. Figure 6 shows the design of the transformer 1:9.
5 Design of the improved
HF- Wide Band Antenna