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Joined: Wed, Sep 30th 2015, 16:52 Roles: N/A Moderates: N/A

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End Fed QRP Antenna Apr 21st 2017, 18:35 6 13,709 on 11/5/22

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End Fed QRP Antenna kd9equ on 21/4/17
I followed instructions on youtube (9:1 unun video) to create an end-fed QRP antenna. Basically a 20 meter half wave 14 gauge wire attached to a 9:1 unun I wound myself on a T130-2 torroid. I tested the 9:1 I created using 450 ohms of resistance connected to the wire end and ground. At that point the ohms were roughly in the 50-60 range. So I went about soldering a 239 end on and installed in a box. Upon putting the wire up in a tree about 25 feet, I am getting high ohms (around 100) and high swr on 20 meters (as in 15:1 or higher). I also noticed that when touching the radio the swr changes (usually lower by 1 or 2 units). The receive noise reduces as well. I suspected a ground issue (which both the videos and docs online say I don't need a counterpoise for this design) . Anyway, I tried a counterpoise but this did not change my SWR any more than me touching the radio. I also tried to put both a ground wire from the radio AND a counterpoise in... Still no luck. I have also played around with the wire length of both the long wire side and counterpoise... I have checked the 9:1 is still good and wired correctly... I have spent a bunch of time researching and haven't found much of anything to try. I am trying to learn along with this process so any ideas / help would be appreciated.

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