No ideal way to stretch End-Fed Antenna (
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- čas přidán 19. 08. 2024
- Scott, KD4EBL, has been trying to find the best possible set up for his 8010 antenna. He would like some suggestions for his set up.
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It sure is interesting to hear about end-fed half wave antennas. I was listening on the air once and was in QSO with someone who explained that half-wave antennas do not require a ground place or grounding. At the time, and this was several years ago, during the conversation I was thinking about something I read and a drawing I saw in the ARRL compendium. a soft cover ARRL publication. Thans to all who made Dovid's video available and poosible.
The EFHW is fun to experiment to see what works best for your application. Mine is between two trees, parallel to the ground and I have had no problem making contacts in South America. That's my preferred configuration. Have also tried it inverted V, sloped up into a tree, sloped down from a tree, inverted L and vertical. The results are always interesting.
I found this setup is performing better than any other- as U mentioned "between two trees, parallel to the ground"
73
vu3tbu
Put up a new MyAntennas 8010 EFHW last night. Near end (plastic connector unit) is at 6 feet high while Furthest end is at 45 feet up in a high tree. No inverted V - just a single straight line. Used my MFJ antenna analyzer and I am getting 1.2/1.4 SWR across all the bands except 1.8 SWR on 30m and 2.1 on 80m. Performance is outstanding in my opinion. Simple to setup and it works very well.
I've built several and they all work great! I have mine as a flat top and have worked plenty of dx QRP and it is only about 25 ft up.
I also built the ARRL efhw 40-10 kit. A fun project in itself, and able to successfully answer a CQ from Solvenia on 17 meters from the UP of Michigan on my first try (100W transceiver). Just a straight slope from 25' to 9'.
As always great understandable presentation. As soon as my neighbor sells and I see who moves in I will be doing exactly what you described. An inverted V 65 more feet on down to their far block wall. Should open things up well. Mostly use 40 and 20 so this will be interesting. Thanks Dave.
Really enjoy all the EFHW antenna videos. Very much appreciated. 73, AC3HT 📶
Great info. My EFHW-8010 goes from 40' down to 20' down to 10' in a modified L and it works FB. My balun is mounted on the high end.
For any current that flows into any radiating element. MUST have and equal amount of current flow into a counterpoise of some kind. If not, it will create its own counterpoise. And thats exactly what an EFHW does, it uses the feedline as a counterpoise.
Well done! Scott may be experiencing "paralysis by analysis". (And don't we all from time to time.)
You peaked my interest with a fan end fed.
I agree with the person that said end fed is the wrong terminology: it should be extremely off center fed dipole. I modeled a fan "end fed" in EZNEC with AutoEZ. To get a good model, you need to include a counter poise.
There is a lot of potential is such a concept. My model had the 80 meter element at 0 azimuth, the 40 at 45 degree azimuth and the 20 meter element at 90 degree azimuth. This 80-40-20 extremely off center dipole model requires a lot of tuning as there are at least 5 elements to tune:
1) the length of the 80 meter element,
2) the length of the 40 meter element,
3j the length of the 20 meter element,
4) the length of the counterpoise, and
5) the unun load.
And one could add height.
I found that tuning to reasonable SWR is possible for all bands but I do not know if I have an optimal tune. The 3D probation fans are quite complex as well as the Smith Chart. The higher frequencies are much easier to tune than the 80 meter value.
But in the end analysis, if one has too much time, this is a fun project to try! It can be done, and I suppose, built! The antenna gains are quite reasonable.
Walt (AI7MY)
All over the place
Nice.........
the best install for a efhw is straight up
All of your examples wind up parallel to the ground. What if you start at 30 ft + on the mast and slant it up to a tree at 50 ft or so, would that be workable (and better than a 30 ft + horizontal)?
OK, I am confused. You were showing a point where the coax comes into radio and the antenna then goes up from unun to a mast to get wire higher. But no w am I wrong in think8ng that a wire going up a metal mast will cause both a mismatch for impedance and also loss of tx signal from the wire through induction? My other concern is because of my limited space, my end-fed is curved at least three tines. Does this cause an issue? 73 N6ZKI
I just built the ARRL efhw kit 40-10M. It works real well for me. KJ7UPY
So on my 4:1 balun I have a lighting arrester right at the balun. According to this the arrester makes it so I can't use my shield as counterpoise?
I was thinking about swapping the balun for a 9:1 unun and run about 124.5' of wire.
A 9:1 unun is normally used with a non resonant end-fed antenna, not an end-fed half wave. With an end-fed half wave using a 50 ohm coax feedline a 49:1 unun is commonly used for the best impedance match.
@@jonmcadams5401 That does not answer the question about the arrester! I know what a 9:1 is used for which is why I built it.
I experimented Endfed . Its work fine. But not radiates lower angle. Not best for Dxing . Dipole is only could radiate its best RF. Vu3kod
An EFHW is a dipole. The only difference is it’s fed at the end instead of the center.
Thank you for your video. Have a great week. N0QFT