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Joined: Sat, Apr 4th 1998, 00:00 Roles: N/A Moderates: N/A

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End Fed QRP Antenna kd9equ on 11/5/22
All sorts of late activity!

The basic issue here is trying to use a 9:1 unun with an end-fed half wave antenna. That kind of antenna has a 2500 ohm resistive impedance at resonance. A 49:1 unun is needed to transform that down to approximately 50 ohms. The 9:! unun will result in a mismatch at the antenna, high SWR on the coax, RF around the transmitter, and poor loading without a tuner.

The ARRL currently sells a half wave end-fed antenna in the shop - you can look at the instructions there. You can also search for EFHW antenna and find a wealth of information. Another good search is: 49:1 unun.

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