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Sloping an EFHW Dipole (
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- čas přidán 19. 08. 2024
- Due to a question regarding dipole sloping from Don Dernat, VE3DBN, Dave explains all about sloping and using EFHW dipoles.
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Thanks Dave. Just put one up in back yard for field day with great results. An understandable clear and engaging explanation as always. 73s de N4KGY
I learned so much more about my EFHW deployment in this video. Thanks, Dave!
Great video about a topic that's often made complicated.
I purchased a 80/10 My Antenna to work with my IC-7300 because I could make it fit into my small back yard. I am also using a LDG automatic external tuner that works with ICOM radios, so that I can utilize the phone portion of the 80 meter band. I live on the east coast and have made contacts in Europe, Texas, Florida, and in some Northern states. Today, I made a contact with a fellow ham living in my community on 20 meters (we were both using an end fed antenna) - so it seems my antenna works NVIS as well as long distance. It is fascinating how mother nature affects HF propagation.
I have a legal limit resonate 135' that I run along with a vertical. I switch between them to all the time depending on which has the best ears and or noise level.
My transformer is near the shack about 15' off the ground with 35 feet of coax. The end is 120 feet up at the top of a big live oak. It has a SWR under 1.5:1 on all bands except 75m general portion phone band. There it was showing 4:1 to infinite.
I read an article how to tame this without affecting the other bands and now have a 1.2:1 on 3.950.
The trick is to cut the wire at the halfway point and add an insulator. Between the two wires add a 220pf 3000v disk capacitor for up to 100w. If you run any power the capacitor is going to need to be a ceramic doorknob.
The article claims it makes no difference on the higher bands but I have found 40m to be 1.2:1 to dead flat across the entire band. Before the mod it was 1.2 to 1.5:1.
I have added 6 turns of coax as a choke behind the transformer as well and have no rf issues in the shack even when running legal limit. I've managed contacts from my qth in North Florida from Australia up to Iceland and over to Japan and the Middle East with 100s of contacts throughout Europe.
I run the same antenna for POTA and SOTA with the same results.
Thanks for answering my question, I have the feed end at 33 feet and the low end well marked at 6 feet. Works well especially for FT8.
Dave, Thank you for your videos. I keep finding conflicting info about the counterpoise for an EF. Some say you should run the counterpoise parallel (under) the wire, others say perpendicular. The choking is also represented in two ways. Some say put an isolation box (LDG 1:1) at the antenna to block RF on the outer coax braid. Some say don't choke at the antenna because that outer braid is the counterpoise but do choke it before it comes into the the shack - for example, if you had an 84 ft random wire, and you were going for 75M, you could choke your coax around 60 ft down the line (quarter-wave of your target freq.). So posts say choke the coax and run your own counterpoise - and again it branches to parallel or perpendicular.
There must be some reason why the people believe what they are posting, but the posts mostly say "do it" without the why or consequence of doing it differently (parallel vs perpendicular). Any insights would be appreciated.
Thanks for the video! Very good information.
I must say I don’t see very much recognition of the content creators coming out of ARRL. All of you have become an invaluable resource for the hobby.
I have several end feeds. Needed this video. Thanks
I've been watching your videos on and off for years. During Hamvention when my best man saw you and expressed his gratefulness for your videos and channel, it seems like CZcams fate brought some of your videos back to my featured list and I've been learning a lot about HF once more. I look forward to learning much more myself, and thank you for your service to the amateur radio community. W8JMO.
Excellent, informative, and most importantly, it didn’t go on for 45 minutes and get overly full of technical jargon. Good stuff
Been doing this a long time. Still learn something new from ya all the time Dave. Thanks a million! :)
I’d recently got myself a sotabeams bandspringer and was wondering exactly this. Thanks Dave!
Once again you’ve expanded my knowledge, thank you!
Strictly speaking a half wave continous wire, end fed, is not a dipole. The term dipole means 2 poles, and if it is broken and fed in the middle it becomes two sections of wire, quarter wave each and then is a centre fed dipole. A single continous wire, fed at one end or the other is really a monopole. The term Di means 2. Just a comment but a good video and an end fed wire can be a very convenient antenna to erect. The feed impedance will be high, usually around 2,500 ohms and so a matching unit or an UNUN will be needed to fed a 50 ohm line.
I'm testing my 66' EFHW now that I've watched your video. Thanks Dave. 73 W8XDX
Thanks Dave for sharing your video & insights. I recently discovered your channel subscribed, and binge watching several of your excellent videos.
My old Home brewed Dipole that was built in 2020, is needing replacement. I’m searching CZcams videos for refreshers, as I had 2 Strokes in 2021 that impacted my memory and brain white matter atrophy.
Dispite this I am determined to venture into the realm of Software Defined Radio yesterday I ordered a Xiegu 90 and considering the Xiegu DE-19, Digital Interface device to refresh my
Ham Radio Deluxe experience.
73 Steve AA4SH
I run a random wire with a 9:1 as a slope. The high end is 16' off a tree and the low end and feed point is 6" of the ground. Coupled with 34 6' radials it has a great pattern on 40, 80, and 160 when modeled in MMANA.
Helpful, thanks.
So my favorite items are, the typewriter and the oil lamp😅
Thanks A lot, Dave this info was explain.
The height above ground will depend on the frequency and whether you want an NVIS (80 & 40 meters) or not. The center of the antenna will do most of the radiation.
I measured EFHW dipole with analyzer and found that this antenna has good swr but impedance is really bad. So antenna radiat a lot energy back to radio..
That’s where you use a matching transformer. I have an end fed vertical for 20m made from aluminium pipe. I wound my own match that was much less than 49:1. Much closer to 850-900 ohms at resonance not 3K as with wire antennas
You’ll also need a good common mode choke at the match end of the coax to reduce common mode currents on the outside of the coax
This is a common problem if your transformer is not made properly.
You have to ground everything to solve this.
Thank you Dave!
Great information thank you, my afternoon project 🤣
⭐️⭐️⭐️⭐️⭐️ 5 star video. Thank You
my end fed is on a sloping garden and is fed at the lower point which is at 20ft above ground, which effectively is 0 ft when compared with "the lawn" at the back of the house. the "other end" is 25 ft above "the lawn, which as the house is an inverted L makes it 10ft above ground with reference to the road. I have had good coverage and worked many countries on 80 through to 6m. Where are the hotspots for "people" to avoid, not that they can easily grab the wire.
Thanks for excellent information David. Just wondering if you could provide some information on how to tune an efhw shorty-forty a coil along the wire. I understand we cut the wires but how? Given it covers more than one band and a there is a coil along the wire.
Higher may be better, but with safety in mind
This is just the info I needed. Thanks! I’m putting a 66 foot efhw in my attic and need to put it horizontal and it needs to snake around the attic to fit. The shape is kind of a “u” with a couple of extra bends. If you see this post, can you let me know if this shaping around the attic will mess everything up? Thanks.
Efhw is not a dipole
ARRL says it is. Good enough for me.😂
Is there a big difference between a center fed slope or a end fed sloper radiation pattern ? That's an important question we all have ! Just found your channel . Thanks for sharing. 🍸
If the transformer is up at the top of the mast how do you provide the counterpoise?
Those mushrooms must be awesome
Question to anybody with experience. I'm putting up a 132ft off center fed dipole long-term. Im under the impression that most ppl simply tie some Dacron onto the dog bone insulators and raise it up. I'm concerned about stretching and longevity. I was considering running Dacron the full length and gently wrapping the 16 awg wires around the rope. Will this negatively impact the antenna? Any thoughts?
2:07 Height is might!! ;-)
A halfwave antenna not a dipole since a dipole has to be broken in the center.
Thanks, Dave, and Don B for the question. I just put up a 66' 80-10 EFHW from a US manufacturer. High end at 27', about 5' off the house, sloping down to 12'. Called manufacturer when the performance was poor. They suggested adding a wire to the 2nd lug on the transformer, dropping that to a separate ground rod, then running a 66' radial underneath the antenna. Helped a bit but still very poor compared to my INDOOR 20M and 40M dipoles. (The 40 M is even in a "U shape" horizontally.) Have not approached the manufacturer about a return yet but this was a waste of money at this point. Any suggestions out there? More radial wires to act as a counterpoise? Thanks for any suggestions!
A question: what is the radiation pattern of a 4m long end fed wire sloping down from the driven end, at 40m, ie a full wave? de 2E0UPK
They tend to be a bit more directional as a sloper
Thanks Dave! I am putting up an EFHW myself this weekend. Thank you for sharing knowledge 👍 - KE8QPI
I am using EFHW in sloper configuration with ubitx. But feed point is at 15' and then it goes up 30' approx.
Works great for me.
But Steve Ellington recommend to get feed point away to avoid rf back in shack as coax shield act as counterpoise.
I had to ground everything to avoid that.
Greetings could you tell me what gain have the EFHW antenna. Excellent your video
W4EDY
what would happen if u put 4 long wires on the endfed n s e w and a counterpoise in each direction??? would that work?
Dave, when/when not to use a conductive mast?
Thanks!
73 N4ANO
Why antenas are valuable it's only cable I can't understand
But I like radio works like waves
I cant understand how radio catch sound by wave I try to understand in few months but I cant so i find some videos in CZcams so i found videoes like your chanel but it's not my purpose I like to find how radio catch sound.
A dipole is centre feed, this is end fed 'EF' therefore is a longwire not a dipole as the EFHW design does not require a counterpoise so is truely end fed
👍👍👍👍👍🙋♂