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ANTENTOP- 01- 2011, # 015

Super Broad Band HF- VHF Antenna

 

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.

 


Figure 3 Aperiodic vertical antenna

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.

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 antenna.

 


 

 

 

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.


Figure 5 Design of the improved HF- Wide Band Antenna

 

 

 

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August 2, 2016 8:55

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