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End Fed Halfwave Antenna And Matching Unit
My favorite antenna for portable use is the end fed halfwave or EFHWA. I have documented some of the earlier ones I built in my pedestrian mobile pages
post 01 Mar 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
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 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
PIC-Keyer This project describes the construction of a real "QRP" keyer with a small microcontroller PIC 16F84, with slightly modified hardware also PIC16F62
RF Inductance Calculator Mean diameter of the air core coil, measured from conductor centre to conductor centre include the wire insulation thickness, if any
Voice Recorder Gestito dall'integrato in questione ed offre la possibilità di registrare più messaggi per una durata massima di un minuto con buona fedeltà di riproduzione