Homebrew EH antenna for 40M band
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- Опубликовано: 3 янв 2018
- This is my homebrew EH antenna for 40M band.
This antenna has the problem with a strong returning RF in to coax. This is the reason why i never tryed this antenna in a real outdoor conditions. Until now i did not solved this issue with RF. There is a big problem with resonant frequency instability due to this.
Special thanks to Larry D Brown (silent key)
... btw, sorry for my english 
Наука
![40M UltraLight QRP magnetic loop antenna + TEST [ XIEGU X5105 ]](http://i.ytimg.com/vi/dcs5srMJamE/mqdefault.jpg)
Hi Paul, Thank you for the video. Don't forget that this part isn't an antenna . It is only a coil and a capacitor which are adjusted to 50 ohms (that is the reason of the good SWR) but in no case, this part will radiate waves. I'm wondering if any OM's could have a normal QSO distance with this "antenna" 🙂..... 73's.
Very interesting.. Thanks for sharing
Looks like a fun project
That was a really well constructed antenna Paul .. A very interesting design... It's nice to see that the search for a 'small' working 40 Meter antenna with a good bandwidth goes on... Mag loops are great, but it's the constant re-tuning that's a drawback. Same problem with loaded whip antennas and narrow bandwidth in the low frequencies. Enjoyed the video and demonstration...73, Pete
Thank you Pete, but there is still problem with strong RF in the feedline. I never used this antenna in the field. The RF changing resonant frequency with all moves of the coax. :) 73, Paul.
Hello from America. I think you did a super job of it. I looked at the craftmanship in the close up shots that you took. I was quite amazed at how professionally wound and connected everything is. I am very envious of your skill!!! Best regards, L.
Oh! Thank you very much for your support! 😊😊
Hi Paul. When you will tested your EH antena on band?
Such interesting videos on your channel. Thank You Paul.
You are welcome 😉👍 Thanks! 😊
Wow! This is really interesting!
This would probably be a very good antenna candidate for use with JS8Call on 40 m.
Thank you for the excellent and very informative video Paul!
Thanks, but in this design is one big disadvantage - strong RF current in the feedline. Therefore you have to use good RF choke if you want to properly tune and use this antenna 😊
@@OM0ET Ah, I see... And it makes perfect sense (if anything electromagnetic does).
I guess antenna building is our modern day black magic or witchcraft: You don't really know how it works or even why you want to suffer through the process since your ideas often seems ridiculous, often are ridiculous, often comes from an old moldy scripture without any provenance whatsoever but with lot's of claims attached - and often cost substantial investment both financially and timewise. Finding exotic materials like unicorn milk, frog eyes and T-240-43 toroids. Learning strange formulas and preparing the concoction before finally casting a CQ-spell, summoning the evil powers of RF, sometimes in front of a highly sceptical crowd... But yet you feel a strong urge to do this time and time again... And if you're not struck dead by lightning - the rewards can be tremendous! 😂
73!
Don't you ever worry about your english, I can understand you much better than few who I know and lives in the USA for decades!! - Excellent job presenting this anternna! - I will build this up and see if can finally have something fit to my apartment. Thank you for posting this, this has been a big help already for hundreds and will be a big help in the future! - Also special thanks to the designer!!
Thank you for your support! 😊 Rather than EH antenna I would recommend to you made the Magnetic Loop Antenna. More bands easier to made. Or the MicroVert antenna. Best regards and 73, Paul. 🙋♂️
@@OM0ET , Unfortunately I don't have any room to rotate a magntic loop :( so this one is pretty much my only hope. Thanks for your response, and stay safe in this difficult time!
Quick question about the returning RF on the coax, do you still have that problem? - if so, did you try to insert a " 1 : 1 un-un " ?
@@zeedee9548 Unfortunately not. I don't use this antenna any more. Now I spend my time to developing of the UltraLight Magnetic loop antennas. They works better and have more bands :)
@@OM0ET Hi Paul, - I finally received the PVC tube (114.3mm) and all the hardware, and I am ready to build this beast. I can only eyeball the length of the cylinders to about 2x of diameter but I assume that it needs to be more accuarte than just trying to approximate it.
Can you please let me know the length of the cilinders? - (I looked for the designer's web site, doesn't seem to exist anymore).
Would the slightly increased diameter require to change the coils or I should just keep all the same as on your video?
No need to apologize for your English, it was very good. I know Americans that cannot speak that well.
Oh really? Thanks! 😁 I am just a self learner... 👍
@@OM0ET You have never been too the deep south in the US. :)
@@tangle70 😄
Don’t apologize for your English, your an accomplished individual. Thanks for the interesting video.
Oh thank you for very nice comment Jason and for your support too! 😊 73, Paul.
Beautifully built!! I have to try to make one. 73Tim VK4QP.
Thanks! You have to made good RF choke too. A lot of RF was in the feedline. 73, Paul
Hi Paul,
Do you have any video with this antenna in action on SSB ?
I would like to see simple performance report with some video to support it.
Regards
S79KW - Seychelles
Sorry but no. I had an issues with strong RFI trough the feed line which caused problems to stay at resonant frequency.
excellent video . Beside, your english is almost perfect. Congratulations . Now, I am clear with this antenna.
Thanks a lot! ;) for the nice comment! Stay safe! 73, Paul.
Great video and an amazing antenna
Would you please consider doing a step-by-step build on this antenna it is so rare and peculiar there’s a lot of confusing aspects it would really be nice to have someone walk us through the process
Hi Paul,
very nice antenna building, looks good.
Did you ever try an rf choke (maybe with ferrite rings) to handle the problem with the high rf current?
Maybe its also neccessarry to take the antenna outside and use a good grounding of the coax near to the antenna itself?
73, Marc
I was going to ask the same thing
The the wb5cxc web page contains a link to an excel spreadsheet for calculating the coils. However, when I try to open that spreadsheet, it says it's corrupt. Do you have a working version of that spreadsheet?
I made a backup because wb5cxc is silent key already and i don't for how long will be this website available. I have complete html code.
OK, I finally got it... thank you very much! This looks like just what I need since moving into a condo. My neighbors wouldn't like it too much if I try putting up anything too big or conspicuous.
73's, Dick - wa0ian
lol this i know, because i live in apartment building so we have 23 families in that building :-)
Hello Paul, it is a nice and interesting video. I have seen that SWR is 1.1, which seems not high, however in your comments, it seems that certain amount of RF power is coming back through the cable, what does it mean exactly? Thanks.
Yes, the problem with this antenna is strong RF coming back trough the coax which cause resonance instability. It needs a good RF choke.
Well done dear it's good design. I am from India. Can you send construction details of this antenna, so that let me homebrew. My id "vu2klg@gmail.com ". Tnx and good luck
Where were all the stations that were transmitting on 40m? I did not hear anything. Also, why didn't you try and have a QSO (in any mode)?
Robert Adlington please read some other comments and my answers. Thanks 😉
Thank you for the video! Good luck, 73!
7jk
hi is there any chance of a build along video where we can watch how you make it and then duplicate what you did as I can follow these types of videos rather than reading plans and making them. keep the videos comming as they are very informative
Hi Phil, due to very strong RF returning in to coax i don't actually plan to made another one. First at all i have to solve the problem with RF which causes strong resonant frequency instability. I realised this issue after this video uploading. 73
Your English is just fine Paul. No need to apologize to anyone about it.......
The EH/ECH/ECFH, or whatever they're being called this century, were quite the rage 15/20/30 some odd years ago but never resulted in any truly functioning radiators.
As I was told as a 5WPM Novice many/many years ago, and latter learned first hand, you can load-up a bedspring and 'Get-Out' if you want to.
In practice, any metalic object will 'radiate' or 're-radiate' RF whether you want it to or not.
AND: There are numerous ways of obtaining a 1:1 SWR at the TXer.
What counts is Near Field then Far Field RF Power measurements, then signal reports!
SIGNAL REPORTS........
This is not meant as a criticism of Paul. I'm just stating some observations and experiences of mine.
BTW: Paul's constructions on any of his projects are always great. Clean/Neat/Very Good Looking. He always does good work!
As another poster has stated, small Magnetic Loops 'WORK' and in my experience, they certaintly do, but also in my experience, EH antennas don't work!
Been There, Done That, Got the Tee-Shirt to Prove it!.....HAHAHA.......
73 to all yuz OMs
Russ in NH, KA1RUW
Hello Russ ;-) Thanks for your nice comment! You'r absolutely correct about this antenna. EH antenna is the one of more of my small portable antenna experiments. Unfortunately I didn't finished this antenna due to high RF current in the feedline and high resonant instability due to this RF current. Definitely EH antenna needs a good RF choke for sure :) By my opinion the magnetic loop antenna works better. ;-) 73, Paul
Interesting, but you could achieve similar results with a dummy load. Resonance is all well and good, but how does it perform for contacts?
Those who have never tried new technology tend to see it as "magic" if they don't understand it.
@@arvevans He has a valid point. What good is it without seeing how well it receives and transmits?
Hi! Nice project, I never heard of EH Antenna before seeing this video. A quick question though... It's okay to transmit while changing the frequency? Sometimes I do the same when tuning but I'm always stressed and try to avoid :)) 73, this is OZ/YO8UFO
Thank you! :) but I never used this antenna in the field due to strong RF in the coax.
What a great project!! I realise this is an old video, but I noticed your SWR meter was set to REF (reflected) power at 7:35. It should have been on FORWARD if want to measure the power going into your antenna. The lower the REF reading, the better. You can see the SWR going up as the reflected energy rises.
No, you set the meter in forward and see the swr in reflected.
What an interesting looking Antenna.. Looks slick.. (I Wonder how well it would work (2m 70cm if downsized accordingly)..👍👍
I have never test it because of resonant frequency instability due to RF influence in the cable, even when choke was used.
@Paul have you tried testing this antenna already? I am currently looking for an antenna that might work in an apartment. Ireally liked all of your videos especially the microvert antenna but it seems my homebrew failed. Hope to get more info and hoe you can test this EH antenna. Keep safe and 73!
I never tryed this antenna in the field conx due to strong RF in the feedline coax. For your indoor purposes I would recommend to you to made Magnetic Loop Antenna. :) 73
@@OM0ET Thanks Paul, very atrong interference here but 'll see if I can do the magnetic loop. Will check you video on that. Thank you!
@@heavyarmsgundam i wish you good luck with Magloop 😉👍
Zdar, nemáš tam náhodou schéma pro CB pásmo? :D
How make?design?blueprint !
In ass -tube lighting!
circuit i need.
wouldnt mind the full schematic and measurements
You can make anything resonate with the proper capacitance and inductance. But does it RADIATE? -- beyond this small room, I mean. After designing and building antennas for over 50 years, I have to say I doubt it. WB5CXC Became a Silent Key just over 7 months ago, so I guess I won't be asking him any questions about this antenna. He admits on his website that some of his designs turned out to be nothing more than dummy loads.
Dave Mitchell i never tryed it outdoors because of high RF in feedline and this causes strong resonance instability of this antenna. So without a good RF choke is this antenna practically still not usable outdoors. This is the reason why i stopped testing it outdoors. I need isolate RF to feedline first. I tryed few chokes but no success. 73
Great demonstration sir! No problem with the English! You pronounced “neon” correctly the first time! “N-ion... “ well that’s a new type of battery maybe! LOL! 73 de KZ3DEL
Thank you! 🙂👍73
Привет Паул! Смотрю видео и вспоминаю себе 40 лет назад. US7ITC 73
This Antenna project is still not finished. I need to made current choke balun ;-) 73 Paul
Common node current problem?
Yes RF current in the coax
Хороший рассказ, хороший тест. Респект из Сибири.
Hi Paul, very interesting video to see on your channel. I wonder or find it very strange that people do not share or disclose the 40m EH antenna design or construction on youtube. I could find a lot of construction and design details for all bands except 40m.
Paul, I would like to build one EH antenna similar to what you have built. Could you provide or reply me directly all details of wire dia with insulation or without insulation, cylinder, source turns, phase turns and tunning coil to my email id?
I had build one of the 40m and 20m EH Antenna published by F5SWN, this antenna was not even close to the desired band. My Kenwood TS-2000 radio could not tune to any frequency as the swr was very high and radio stops auto ATU mode even with 5Watts of power.
Thank you very much for watching my channel! All what you need can find here on this website: www.wb5cxc.com/design_eh.html I am not professional but I can help you as so as possible. I used 1,5mm copper wire with PVC insulation and wide tubing, but in this moment I don't dont remember this diameter but i guess 160mm. Cilinders were made of thick layer alluminium foil. But my EH antenna has a problem to maintain stable resonance frequency due to RF in the coaxial cable. I have to made a good RF choke. ;-)
@@OM0ET Thanks a lot for your prompt reply. Hopefully I should be able to build one 40m EH antenna these weekend.
@@prakdavid3559 well, let me know when you will be done with this antenna. I wonder how it will work. ;-)
ok.Nice Job.. But. Im not hear to any station, no contacts for Demo?. The Antenna are made for using it. not for Check SWR. 73
YV5EMG HAM RADIO hello this antenna was no longer in use because there is a problem with high RF in feedline coax what causes big resonant frequency instability of this antenna. It needs some RF choke on it.
OM0ET RR. Keep going experimenting. And thanks for sharing. 73..
Thanks for the video, and your English is pretty good. KD9GRP
☺ really? Thank you very much! 😉👍 73 Paul
Do you have any plans building a 20 meter version of this antenna ? If so, showing the build process would be very helpful, for us just learning to build antennas. 73 BOB @@OM0ET
@@322doug I am not sure to build 20m band EH antenna. This 40m version is still not finished due to high RF level on feedline. I need to make 1:1 current balun. :)
ok, cool thanks @@OM0ET
Who never tried, who never learned.
After you try it you are smarter.
I have already tested the EH antenna, with the same result which you had ;-)
I even tested them, never had a qso.
I think it was a mistake.
Lesson learnd ;-)
73 Bernd
yes, it's my job here on this channel :-) made and test experimental home brewed antennas and then some are working some not. This one I never tryed in real conditions because I need to made choke balun due to high RF in the coax feed line. Then I want to test it outdoors :-D I am curious if I will make some QSO. I want to share results on my chanell too for sure :-) 73 Paul OM0ET
So it emits something in near-field... If you ever do further experiments with any EH antenna designs, successful, informative or unsuccessful (depending on one's philosophy!), that would be interesting to hear. I read your replies to others about instability issues, would be interesting to hear of any fix attempts.
My friend has this antenna that his industry care about long-distance
QSO?
I never used this antenna and didn't had the QSO :) Strong RF current in the coax cable.
Il mio amico può mostrare chiaramente le misure in cm
Pali je to super urob aj slovensku verziu
Dominik Ujcek vdaka! Uff uvidim ci sa dam este aj na slovensku verziu ;-)
Watch your plastic column ! Most of the power is going there ! 🙈
You need a choke balun to stop the coax feeder radiating. EH antennas are pretty useless.
Yes I mentioned it several times in the previous comments.
My friend may show measurements clearly in cm
Hello. It's very simple to convert. 1mm = 0.1cm or 1cm = 10mm 😉👍
shukraan sadiq
Thank you my friend I have a wireless device Uhf70 watts if possible I want a strong antenna Yamen connection 70 km I want advice from you Thank you
If I understand correctly, you need a strong antenna for 70cm band UHF and you want to make a stable contact to station 70km far away from you? If so, I recommend to you to buy LFA Yagi like this:
www.innovantennas.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=86&virtuemart_category_id=13&Itemid=182&lang=en
Neat construction, but your information is a long way out of date. More importantly nothing here shows the EH antenna itself is radiating. Look up my callsign M0RZF for why I no longer research these antennas.
Robert Brown i agree, EH antenna is radiating also with coax and that causes that antenna resonance was very unstable. When i touch coax resonance changed. That was not usable.
A ferrite choke will stabilise tuning. The performance is always about 2 'S' points worse than a conventional antenna. I found the Poynting vector synthesis principle is not a workable idea, and so I am now working on alternative ideas.
I tryed ferrite but i was not succesful :-(
You need >1m of coax from the EH, then 3 or 4 turns through a large type-43 ferrite. The impedance of the choke must be high, then tuning is stable but a network analyser helps!
Thank you very much Robert ;-)
????? 20% of 100 watts is 20 watts, NOT 4 watts
Not sure why that would be, maybe the antenna's impedance isn't 50 Ohm? Also I dont know why iCom uses this percentage thingy instead of actual watts! :/
The longer the coax the better. I'm sorry but the EH is a joke. Wanna good portable antenna that really works? the magnetic loop antenna is the way to go.
73
Speciality, not special...
No sense. Antenna test in the building. This antenna, like any other, works properly outdoors. At least 1/2 wave away from buildings. A pointless movie for me. Make a dipole for any band and put it in your room, we'll see how it works
Instead of *_QRM-ing_* the 40m band, make some DX contacts to show just how _terrific_ your antenna is. *FAILED!! THUMBS DOWN!!*
Please read also my previous comments. I explained why i did not tested this antenna outdoors...73