EFHW End-Fed Half-Wave Antenna Kit | Part Three: W1AW POTA ACTIVATION
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- Опубликовано: 18 апр 2022
- In this PART THREE video, join the ARRL team as we head to The Windsor Locks Canal State Park in Connecticut to put the End-Fed Half-Wave Antenna Kit (EFHW) to the ULTIMATE TEST with a POTA activation resulting in many contacts! ARRL member Rob Zielfelder, Jr., N1NUG, is joined by ARRL CEO, David Minster, NA2AA, and W1AW Station Manager, Joe Carcia, NJ1Q. See how the antenna kit preformed!
Check out PART TWO: • EFHW End-Fed Half-Wave...
Check out PART ONE: • EFHW End-Fed Half-Wave...
For written, step-by-step directions, visit: www.arrl.org/end-fed-half-wave...
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To purchase an End-Fed Half-Wave Antenna Kit, visit: home.arrl.org/action/Store/Pr...
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Special thanks to Rob, N1NUG, for his help with this video! Check out his channel, SevenFortyOne: / sevenfortyone
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Special thanks to Parks on the Air (POTA) parksontheair.com/
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I had bought this kit a month or so ago...thanks for the tutorial from build to deploy...it will be in my backyard...great trees....and easy to set up. Thanks
I can't believe that guy was taking in Morris Code without a pen! WOW.
Excellent activation guys, well done Rob, David and all involved! The ARRL EFHW kit looks the business.
A nice series of videos - thanks for all the work. I bought this same kit from ARRL just before Field Day 2021, suspended it between two masts at our EOC, and had a great time. A year later it is still working at my QTH, albeit with a ~130' antenna wire to support 80M. We may plan an HF antenna-build class based on this design for our CERT members who recently received General licenses. (Using an inexpensive nanoVNA, PC and projector makes demonstrating the SWR graph to a class a snap.)
K2TNO
I built the ARRL EFHW antenna prior to ARRL SS CW in early November, 2023. I use a 17-foot counterpoise wire stretched along the ground below the box. I made one change that is worth considering: Instead of the grey plastic box supplied with the kit, I opted to visit my local electrical-parts supply store and bought a grey plastic weatherproof electrical box. It is a 4" w x 4" d x 2" h. It has a better sealing gasket, and also has two built-in mounting tabs that are on opposite sides of the base. This feature makes it easy to secure the box to a fence post or other support near ground level.
I wrap several turns of my RG8X coaxial cable around an FT240-31 mix toroid at the feed point, to act as a common-mode choke.
I have an Elecraft K3 transceiver, that provides two antenna inputs and has a panadapter spectrum display. Those two features allowed me to compare the EFHW antenna to my other antenna, a Comet hf multiband end-fed vertical. During the Sweepstakes contest I could switch back and forth and compare signal levels from stations at known distances from my QTH on the coast of North Carolina.
Surprisingly, [at least to me] I found that the two antennas were almost always equivalent--- despite one being vertical and the new ARRL EFHW being a "sloper" with the far end about 30 feet above ground. I rarely could see a signal strength difference on the spectral display peak heights, regardless of distance or direction. Recall that SS is a USA/CANADA-only contest; I have not given the pair a serious evaluation for DX.
There was one consistent difference, that was true on all bands from 7 MHz to 28 MHz: The wire EFHW was consistently about 6 dB noisier, when I compared the baseline noise amplitude of the two antennas on the spectral display. Our neighborhood has buried electrical lines, and I even went so far as to shut off all AC to my house and powered the transceiver from my emergency 12-volt storage battery. The noise difference was still present.
In sum, the EFHW antenna is a good SWR match on 7, 14, 21 and 28 MHz as the manufacturer states.
ONE CAVEAT: The hardware supplied is metric; it is helpful to have small metric socket wrenches or end wrenches to aid in tightening the fittings. In my case, I opted to exchange the metric hardware for standard US-threaded stainless steel hardware, all of which I had already anyway.
As far as construction goes, the only expensive detail to worry about is the need for a suitable drill for installing the UHF coax fitting. I used a "step-drill" that I already owned, but they are expensive if you only plan to use it once. An alternative is to buy a suitable drill of the correct diameter, that might need to be ordered on line.
Bottom line: I fine way to get a working HF antenna at reasonable cost and complexity. It won't out-play your next purchase: Stacked 4-element yagis 🙂
73
Great social media work, Dave!
Well done!
I had the idea a national representative body like the ARRL would be a little staid and bureaucratic. Nice to see them engaging with this kind of activity directly! The US has such marvellous national parks and nature, what better way to engage with it as a ham than SOTA and POTA? 73 de VK4QP.
Nice series! We will be using this video series to build the EFHW for Sussex County Charter School! Be sure to look for us sometime after the Spring Break as KD2YAQ :)
That’s the Park I activate every Sunday. I have used the same tree. Now I just back up my truck and use my WRC. 73, KC1PSK
Nice video. Always nice to have a helper with you (who has that? lol). Thanks.
Nice kit, it can take a fair bit of power for an end fed.👍
I am not an antenna expert, but the power limitation is, I believe, mainly determined by the transformer. The kit, as supplied, had no trouble handling 100 watts SSB phone. But with ~60 watts digital running Winlink, the core heated and SWR rose. It seemed to handle 40 watts with FT8, PSK31 and even Winlink. If you need more power, add a second, or even third, transformer toroid. I also up-sized the gauge of the wire winding the toroid.
Have fun
Thanks for the video series, it was helpful as I bought this kit and put it together. I do have a question, is the connection point next to the antenna coax input for a ground or is it for a counterpoise (ie., radial)? Is this necessary? Did you use one for your POTA activation? Thanks!
is the activation log going to be submitted to POTA for hunter and activator credits? hunters will not get credit for POTA contacts if logs are not sent in by the activator. keep looking for the activation numbers on the POTA site for W1AW, al ve3gam
Why no mention of counter poise?
Why not use that exact antenna run vertical in an inverted L? Almost as easy to deploy. Would work better, yes?
Are you using a counterpoise with the Efhw
Did you check RF exposure from the antenna? Seems the feed point is quite close to the operator!
So you didn't use any counterpoise or ground or choke?
I am watching this video on a Samsung 82-in television and I do not see the counterpoise wire. There was also no mention in the previous video about it being attached didn't see it in the previous test. Also no mention of what length that it should be if it was attached. I suspect there is a measurable amount of common mode current on that braided shield of the coax.
I had the very same questions. I did very much like the set of videos on this subject.
I believe the coax, transceiver housing, mic, key and battery act as the counterpoise. Also, because the antenna is fed at a very high impedance level, capacitive coupling to the soil and other surrounding objects also act as a counterpoise.
Is all that done without a counterpoise???
Ok, but what the heck is POTA? It's customary if you use an obscure (maybe not to you but it is to me) acronym that you initially put it's meaning in parentheses the first time it's used. I've been in active for a few years and recently renewed my ticket.
Doug Lindauer AK4WK, formerly N4HQ, formerly WB2HBM
Parks On The Air
10.21. MHz.
typical millennials, always looking down at the devices, missing all the beauty around. i also agree, one of my favorite things to do when i go to a park is look at my phone to see if i got any texts :D
...loved, loved, loved this!! Thank you, gentlemen, so much!!! de KO4UMY
after watching these 3 videos, I have ordered one of these EFHW antenna kits. not cheap, adding the cost of our dollar and shipping adds quite a bit to the price, but it looks worth it, al ve3gam
You can buy a toroidal core on-line (e.g., from FairRite) and 90% of the remaining parts at a home-supply store to save money. I did that for my second EFHW.
Very good! 73 de PY2SFA