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End fed antenna
Un trasformatore 1:64 su cui e' collegato un filo lungo lambda/2 della frequenza prescelta. una versione a 3 o 5 bande in modo da avere maggiori chance su piu' frequenze. Un filo di rame teso ha un'impedenza superiore ai 3.3 K ohm e quindi per poter adattare l'impedenza ai 50 ohm della radio, con un toroide FT240-43 - 1:64
post 08 Jun 2024
Antenna End Fed Links →
160 meter end fed
With this length of wire a coil of 11 turns is required, resonating the antenna on 1.950MHz with an SWR of 1.5:1
10 20 40m Endfed antenna
It's has a large bandwidth with a low SWR and has no radials
40m End Fed Half Wave EFHW Antenna
The feed point of the EFHW is in the order of 3000 to 5000 ohms while the 1/2 wave dipole will be closer to 50 ohms in the inverted V configuration
60 Meter End Fed Half Wave Antenna Tuner
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With this length of wire a coil of 11 turns is required, resonating the antenna on 1.950MHz with an SWR of 1.5:1
It's has a large bandwidth with a low SWR and has no radials
The feed point of the EFHW is in the order of 3000 to 5000 ohms while the 1/2 wave dipole will be closer to 50 ohms in the inverted V configuration
23cm Yagi Antenna building Finished antenna at 1275 MHz SWR under 1:1.5 at resonant frequency
50 MHz preamp Gain 26dB with the BFG135 Preamps for 144 and 430 MHz, for 50 MHz, the BFG135a is a cheap transistor and in my view rather strong. It is not easily damaged by static discharge or RF power. FG connection
30 Volt Computer Power Supply Stack A bonus was that i discovered that these did not need a standby load connected to the supply to keep them running just apply mains power and close the Start lead to ground