HF Antenna - 40 - 10m Self Build EFHW

[@thestonerguy5276]

Timely Video Peter! Your instructions and advice are always extremely welcome. Thank You again. 73

[@watersstanton]

Very welcome

[@alandrury9955]

Great antenna. Use one myself and have built several others. Regarding the counterpoise/earth, the key thing to grasp is that the outer of the coax you're feeding it with IS the counterpoise - you don't need one because you've already got one! As long as your line isolator is at least a few metres down the coax away from the UNUN then it works just fine. Great for field days and portable use, and great for those with an upstairs shack where an earth would be problematic

[@brianfields4479]

Thanks for sharing Peter, great video. No, I have never bought a ant, but I have made quite a few, including this one. 73.

[@watersstanton]

Cool, thanks

[@ThumpMaster6]

Glad to see you coming to the iPhone video revolution Peter...and your timing was perfect with this one, as autumn is POTA & outdoor activation season! EFHW for the (portable) win!

[@watersstanton]

Great.

[@LouiseBrooksBob]

This is my favourite antenna for portable operation. Just one 6 metre roach pole, inverted V, I have worked Argentina on 6 watts upper side band.

[@davidwalle5025]

Good video. I like your method of winding the transformer very straight forward

[@DonDegidio]

Hi Peter, Great info in the video, however I counted 15 turns on the UnUn several times to be sure. That would make it a 56:1. I believe the rule is every time the wire passes through the core it is a turn. I'm interested in why you started counting at zero. 73 WJ3U

[@hansblommers6088]

@hansblommers6088 10 uur geleden The point where the wire, connected to the shield of the coax first touches the firite core is the starting point of the first turn, Peter calls that the 0 point, the next time the wire passes that exact same point on the core is 1 full turn. Counting the times that the wire passing though the core is not correct. Peter explains it at: 14:12 min, also that the amount of turns is a bit over 14 due to construction. So the impedance transformation will be somewhere between 49 an 56.

[@andre4z620]

Thank you for indicating the measurements also in the metric system

[@watersstanton]

Yes I get slammed if I don’t include metric. And yet we still have 2” pipes and 4” screens! 73

[@johneckert1690]

You talked about using 67 feet of wire for the EFHW antenna on 10, 15, 20 and 40 meters., and it just so happens that 67 feet is a quarter wave in 80 meters so if you are like me and stay up all night due to your work schedule you just bypass the un-un. As always please check your VSWR before proceeding. On a personal note Peter, how is you wife doing? If I remember correctly, I think you stated she had mouth cancer when I told you that I have stage 4 head and neck cancer. My XYL and I are keeping both of you in our prayers.

[@watersstanton]

Many thanks for your prayers. She is well on the way to recovery and just able to eat soft food. We will both pray for you. God bless. Peter.

[@GaRbAllZ]

I will give it a try! Thanks

[@TheDk3bi]

Thank you very much for this very practical instruction. But, I have a question about the number of turns on the core: I have learned that one wire going through the centre of the core is regarded as one winding. If I counted that correctly, in your auto transformer there are in total fifteen wires going through the core. Between the ground end and the tap I count three wires. So in my opinion the winding ratio is three to fifteen. That is an impedance ratio of 1to25. I have been using such an EFHW for some months now and I found that in practice a lower ratio than 1to49 works better. So, your 1to25 ratio might be an improvement.

[@watersstanton]

I have compared my version with a couple of commercial designs and the only difference is a slightly difference in frequency response. Across 2.5K load they were identical.

[@davidportch8837]

another great, practical video peter... many thanks...

[@watersstanton]

Glad it is helpful .

[@muddy11111]

Nice video. It would be good to have a review of your linear power supplies, as there is no information readily available for them. Have tried asking W&S, via the web page, but no reply. Having purchased an FT-710 from yourselves, which I'm delighted with, I need a bigger power supply to use it's full potential. I've seen your video on switch mode, but I suspect a linear would meet my needs better. Keep up the good work.

[@CamilleCullen-ow6qj]

Very nice video, many thanks! Robert K5TPC

[@watersstanton]

Thanks again!

[@reedreamer9518]

I've never owned or used a store bought HF antenna - what fun would that be?

[@ROBByJONEs-2]

Peter id like to request a specific subject on a future video please. its related direct to this 49:1 [ish].. tell us or show us how to determine turn winding for irregulat transformers like 600 ohms to 50 for balanced. or just general how to for bal or single wire..i underastand 2 in 14 is 7 then 7 sq is 49:1 etc but turns ratio please on ring please..im nit making myself clear sorry. instead of just math show how that comes out in real world winding..ty Sir. i love your stuff as always.5 star stuff

[@watersstanton]

Hi there. If you search on Google for RF transformer calculator there are a few you can use.

[@alanrobnett336]

I use 20 meter of washing line (steel inner) from asda £1:50p and use a terminal block to connect to coax

[@watersstanton]

Thanks for sharing that.

[@JamesGoodwill-z1s]

Hi Peter, excellent video, as usual. I'm putting up a 40m EFHW for my home station. With regard to a 1:1 line isolator, should I have one at the feed point as well as at the transceiver end of the coax, or will one at the transceiver suffice? Thank you for all your efforts in putting these videos togther for us all. James.

[@watersstanton]

No, don’t. use one at the antenna end.

[@JamesGoodwill-z1s]

@@watersstanton Will do. Thank you Peter. 👍

[@ChaplainDaveSparks]

I have noticed a few EFHW kits that say *_10-40 meters,_* but I'm not sure why, because they are just an UNUN and winder. Why not 80 meters with an appropriate length of radiating wire? I was wondering if the (supposed) limitation was due to either the value of the capacitor or the ferrite mix used. *73 de AF6AS*

[@ThumpMaster6]

@@ChaplainDaveSparks There’s no difference other than doubling the radiating length to 40m, plus or minus for finding best resonance points. Cut a longer wire, and either work well in inverted L configuration, giving you vertical and some-directional properties.

[@watersstanton]

It will also work fine if you use 40m of wire as an 80 - 10m antenna. I think I mentioned this in the video. Have fun.

[@LouiseBrooksBob]

40-10 metres is more manageable particularly when portable when you will most likely be working during the day when 80 metres is less suitable, but for winter with the long nights, and at a home QTH with a big garden, why not?

[@ChaplainDaveSparks]

@@watersstanton I understand and believe you. I was just wondering why sellers of _EFHW kits_ don't seem eager to make that claim. *73 de AF6AS, Southern California, USA*

[@JH-jp9sv]

@@watersstanton FB and a good video Peter! For an 80m EFHW you may want a tiny bit more impedance in the form of a coil of about 4.5uh 2m form the coax end. I often make the antenna out of magnet wire and 3D print the coil form for the near end. 16 or 17 turns on a 20mm form are fine. This brings all the higher band resonances closer to ideal. Edit to clarify: 2m from the coax on the antenna wire itself.

[@mariemccann5895]

What do you mean by a 'line isolator'?

[@watersstanton]

See text link below video.

[@mktwatcher]

Nice video. I think I will make this. However, can you pls clarify your comment about using a Line Isolator just before the first piece of radio equipment at about timestamp: 19:38 is that different from a lightning arrestor? If not, can I add a lightning arrestor and where would it go? Thank you

[@rossbassette7518]

A lightening arrestor is a different item and self-destructs with a catastrophic electrical surge . A line isolator helps prevent common mode current from going back to your shack while you operate

[@watersstanton]

Line isolator can easily be made. Use a similar ferrite core and weave around ten turns of the coax feeder around it. Search on my site for line isolator. Cheers. Peter

[@JH-jp9sv]

His reply for a line isolator is spot on. If you head down to watersstanton and want to buy one off the shelf you might want to ask for a 1:1 current balun.

[@georgeholman6745]

What is the material (i.e., mix 31, 43 or ??) and size of the toroid core? - I got to build one of those!!! 👍

[@migsvensurfing6310]

Start of the video gives you the answers.

[@georgeholman6745]

Thanks for pointing to the info for me. I don't know how I missed that.

[@JH-jp9sv]

Material should be 43 type. Bigger size means more power handling capability and know that you may need a turn or two more on a smaller 140 to get the same result.

[@HamRadioN0CKL]

Could you do a video sometime that explains why some hams say a yagi is better than an efhw for example? I get that you can get dbi gain in a given direction with a yagi, can dbi gain not be achieved with an efhw?

[@watersstanton]

I think you have answered your question. Yagi antennas have forward gain and rear suppression . EFHW has neither

[@HamRadioN0CKL]

@@watersstanton but is a yagi only better in directional gain? Does an efhw have an advantage in other ways that a yagi doesn't?

[@andye2005]

@@HamRadioN0CKL A Yagi is usually single band and directional, so you have to "aim it" in your preferred direction. HF Yagi's are usually electrically shortened with tuning coils. to make them rotatable, but they are still big lumps of alloy. The EFHW is multi-band and can be bent into all sorts of small spaces. I've only got 30 ft or so length to the bottom of the garden So the EFHW bends back on itself in a lazy V I also have a coil to at the end to enable me to add 80m with is a few feet of wire rather than another 20m of wire. It works, not well but it gets out of 80 and is better than nothing, The Yagi will normally give a better signal in its main direction than the wire. But if you can't fit a yagi in your garden that's a moot point 🙂 Andy

[@HamRadioN0CKL]

@andye2005 thanks 👍 I ask because i see so much hate on EFHW Antenna. Especially when you even mention the idea of using an amplifier with one.

[@kd8opi]

End fed half waves are one antenna I’d never build, because the cost to buy the individual pieces of the same quality of whole assembles companies like Par (Vibroplex) is equal if not greater. Before MFJ went out of business a few months ago, they were still selling good EFHWs for $50. I bought their low power, 25w EFHW for under $40 in 2021. Additionally, you can get an EFHW with a trap that will take the length to 40’. One antenna I would (and just did) build is the VE7CA multi band wire Yagi. Now I have a 2 element beam on 20, 15 and 10 pointed west from my house in the eastern US superior to my EFHw…as long as the station is west of me. Build what you can’t buy, and vice versa. I won’t say it was easy, but it’s worth it.

[@birdhouserocket]

Always very practical, common sense and great explanations from you Peter. Thank you so much. I would love to hear you talk about magnetic loops. With weather turning cold, that could be a great indoor build. Thank you again and 73. de KE8TBM

[@watersstanton]

You are very welcome. Thanks for your support.

[@pierrefchenier471]

Would a 2.4" mix 31 toroid would work as well?

[@watersstanton]

Never tried it. But 43 mix or higher is recommended.

[@pixeluser175]

1:09 Music

[@johngriswold]

I’ve built two this week! Tnx/73 KK1X

[@LouiseBrooksBob]

I wish 30m and 15 worked together with an EFHW. They would be a good combination for portable CW operation but 15 doesn't seem to work harmonically with 30. Unless anyone has done this and knows a trick for getting them both on the same antenna.

[@jomckarth4836]

nice, i like these tutorials, thank you! btw; can i insert a coil 110uH for 80m at the end of the 20m wire and extend with a wire about 1.5m for adjust?

[@watersstanton]

Yes you can!

[@larrychristensen5917]

What is the difference between an autotransformer and transformer? I have been using the auto with great success. Larry NA0F

[@watersstanton]

Direct coupling as against inductive coupling.