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Accordatore per QRP portatile autotrasformatore per EFHWA
Autotrasformatore con secondario isolato per fare dai 10m ai 20m in portatile
post 16 Apr 2024
Antenna End Fed Links →
End fed antenna lambda/2
drastically lower the impedance with a toroid FT240-43 on which we are going to wrap 14 + 2 coils of copper from 1mm
End fed 1/2 wave matching system end feed
Actual bandwith is more than 2 Mhz with VSWR better than 1:1,7 For 14 Mhz you need approx. 10 meters of wire, abt. 4,7m coax-cable 50Ohm or 300Ohm with a connector about 30cm from the shortend end
End-Fed Half-Wave Antenna & Tuner
The final device tunes a resistive load of 3-7 kilo-Ohms from 3.2 MHz to 12.6 MHz. 40 metres is covered and 30 metres too, but I lack a transceiver for it currently
160m mini portable End Fed Half Wave Tuner
The schematic of what I've used. The capacitor is a fixed value because little tuning is required. The antenna can be further tuned by altering the length of the antenna
HF End Fed Half Wave
The SWR is likely to be below 1:1.5 and when used as an omnidirectional vertical the low angle of radiation typically with a maximum at about 20 degrees will give good results on DX
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drastically lower the impedance with a toroid FT240-43 on which we are going to wrap 14 + 2 coils of copper from 1mm
Actual bandwith is more than 2 Mhz with VSWR better than 1:1,7 For 14 Mhz you need approx. 10 meters of wire, abt. 4,7m coax-cable 50Ohm or 300Ohm with a connector about 30cm from the shortend end
The final device tunes a resistive load of 3-7 kilo-Ohms from 3.2 MHz to 12.6 MHz. 40 metres is covered and 30 metres too, but I lack a transceiver for it currently
The schematic of what I've used. The capacitor is a fixed value because little tuning is required. The antenna can be further tuned by altering the length of the antenna
The SWR is likely to be below 1:1.5 and when used as an omnidirectional vertical the low angle of radiation typically with a maximum at about 20 degrees will give good results on DX
Take off angle of horizontal antenna For horizontal polarization, the electric field will move sideways on a horizontal plane, while for vertical polarization it will oscillate up and down on a vertical plane
Rx antennas 4Square Rx Vertical Array My frequency design of 1.825 MHz a 90 degrees line would be 33,70 metersinstead of the previously calculated 33,27 m
Calculo da Antena Bazooka A double bazooka antenna is a combination that has a complete coaxial wave multiplied by its velocity factor and a total end-to-end length of 1/4 wave for each side affected by another driver shortening facto